The natural course of sensitization and allergic diseases from childhood to adulthood

The impact of maternal anxiety during pregnancy on children's eczema and allergic rhinitis: The Ma'anshan birth cohort study

OBJECTIVE

The objective of this study was to investigate the associations between maternal exposure to anxiety during pregnancy and the susceptibility of offspring to eczema and allergic rhinitis and the possibility of sensitivity periods and cumulative effects.

METHODS

The study's sample consisted of 3160 mother-child pairs from the Ma'anshan Birth Cohort Study. Maternal anxiety was repeatedly measured in the 1st, 2nd, and 3rd trimesters of pregnancy using the Chinese version of the Pregnancy-Related Anxiety Scale. Information regarding children's eczema and allergic rhinitis diagnoses was collected through parental reports at 12, 24, 36 and 48 months of age. Binary logistic regression models were used for statistical analysis and corrected for multiple comparisons using the false discovery rate (FDR) method.

RESULTS

Children whose mothers experienced anxiety throughout pregnancy had the highest odds of developing total eczema (aOR 1.45, 95% CI 1.02-2.07) and total allergic rhinitis (aOR 1.67, 95% CI 1.17-2.37) between the ages of 6 and 48 months. The higher the trajectory of the maternal anxiety scores throughout pregnancy, the higher the odds of total eczema (aOR 1.65, 95% CI 1.14-2.40) and allergic rhinitis (aOR 1.84, 95% CI 1.28-2.66) in their offspring. The association between maternal anxiety and children's eczema was mainly concentrated in the first 24 months, whereas the association with allergic rhinitis was mainly concentrated in the 36-48 months.

CONCLUSION

Maternal anxiety during any trimester of pregnancy, especially with a consistently high trajectory of anxiety scores, was associated with higher odds of children's eczema and allergic rhinitis.

Atopic March or Atopic Multimorbidity-Overview of Current Research

The atopic march encompasses a sequence of allergic conditions, including atopic dermatitis, food allergy, allergic rhinitis, and asthma, that frequently develop in a sequential pattern within the same individual. It was introduced as a conceptual framework aimed at elucidating the developmental trajectory of allergic conditions during childhood. Following the introduction of this concept, it was initially believed that the atopic march represented the sole and definitive trajectory of the development of allergic diseases. However, this perspective evolved with the emergence of new longitudinal studies, which revealed that the evolution of allergic diseases is far more intricate. It involves numerous immunological pathological mechanisms and may not align entirely with the traditional concept of the atopic march. The objective of our review is to portray the atopic march alongside other patterns in the development of childhood allergic diseases, with a specific emphasis on the potential for a personalized approach to the prevention, diagnosis, and treatment of atopic conditions.

National situation, trends, and predictions of disease burden of atopic dermatitis in Chinese children and adolescents

Background

Atopic dermatitis (AD) is an important global health problem affecting children and adolescents and detailed national information of disease burden in China is lacking. We aimed to evaluate the national disease burden of AD in Chinese children and adolescent, to provide the temporal trends over the past 30 years and to predict the burden for the next 10 years.

Methods

The data of AD in China, including incidence, prevalence, and DALY, and population data were obtained from the Global Burden of Disease Study 2019 (GBD study 2019), which were estimated using the DisMod-MR 2.1. We analyzed the three measures by age and sex; the age groups were <5 years, 5-9 years, 10-14 years, and 15-19 years. The joinpoint regression analyses was conducted to assess the temporal trends from 1990 to 2019. The Bayesian age-period cohort (BAPC) model was used to predict measures from 2020 to 2030.

Results

In 2019, the highest incidence case and rate were observed in <5 years group; for prevalence and disability adjusted life year (DALY), the groups of <5 years and 5-9 years showed similar higher levels and the groups of 10-14 years and 15-19 years had similar relatively lower levels. Overall, the male-to-female ratios were >1 in <5 years group and <1 in 10-14 and 15-19 age groups. The trend analyses found an overall trend of decrease in cases of the three measures; in recent about 3 years, slight increase trends were shown in cases and rates of the three measures in <5 years group. The prediction analyses found a slight decreasing trend for cases of these measures and a slight increasing trend for rates of these measures in the <5 years group in the next 10 years; the 5-9 years group was predicted to increase slightly in rates of the three measures.

Conclusion

In conclusion, the groups of <5 years and 5-9 years are two important populations that need targeted measures to reduce disease burden of AD in China. Regarding sex disparity, we should pay more attention to males in <5 years group and to females in 10-19 years group.

Facial atopic dermatitis is associated with sensitization to cow's milk, egg whites, and peanuts in children under 36 months

Atopic dermatitis (AD) in early childhood often precedes the development of food sensitization and allergy, but the role of treating AD to prevent food allergy remains poorly understood. Our objective was to assess the relationship between facial dermatitis and food sensitization to cow's milk, egg whites, and peanuts in early childhood, as aggressive treatment of facial dermatitis could serve as a potential opportunity for food sensitization prevention. By 3 years of age, food sensitization levels to cow's milk, egg whites, and peanuts were 48% greater in children with facial AD than in children with no facial involvement of their AD. Additional research is needed to determine if facial involvement of AD in infants and young children is associated with increased food allergy.

Allergic disease trajectories up to adolescence: Characteristics, early-life, and genetic determinants

BACKGROUND

Allergic diseases often develop jointly during early childhood but differ in timing of onset, remission, and progression. Their disease course over time is often difficult to predict and determinants are not well understood.

OBJECTIVES

We aimed to identify trajectories of allergic diseases up to adolescence and to investigate their association with early-life and genetic determinants and clinical characteristics.

METHODS

Longitudinal k-means clustering was used to derive trajectories of allergic diseases (asthma, atopic dermatitis, and rhinitis) in two German birth cohorts (GINIplus/LISA). Associations with early-life determinants, polygenic risk scores, food and aeroallergen sensitization, and lung function were estimated by multinomial models. The results were replicated in the independent Swedish BAMSE cohort.

RESULTS

Seven allergic disease trajectories were identified: "Intermittently allergic," "rhinitis," "early-resolving dermatitis," "mid-persisting dermatitis," "multimorbid," "persisting dermatitis plus rhinitis," and "early-transient asthma." Family history of allergies was more prevalent in all allergic disease trajectories compared the non-allergic controls with stronger effect sizes for clusters comprising more than one allergic disease (e.g., RRR = 5.0, 95% CI = [3.1-8.0] in the multimorbid versus 1.8 [1.4-2.4] in the mild intermittently allergic cluster). Specific polygenic risk scores for single allergic diseases were significantly associated with their relevant trajectories. The derived trajectories and their association with genetic effects and clinical characteristics showed similar results in BAMSE.

CONCLUSION

Seven robust allergic clusters were identified and showed associations with early life and genetic factors as well as clinical characteristics.

Dietary digestible carbohydrates are associated with higher prevalence of asthma in humans and with aggravated lung allergic inflammation in mice

BACKGROUND

Dietary carbohydrates and fats are intrinsically correlated within the habitual diet. We aimed to disentangle the associations of starch and sucrose from those of fat, in relation to allergic sensitization, asthma and rhinoconjuctivitis prevalence in humans, and to investigate underlying mechanisms using murine models.

METHODS

Epidemiological data from participants of two German birth cohorts (age 15) were used in logistic regression analyses testing cross-sectional associations of starch and sucrose (and their main dietary sources) with aeroallergen sensitization, asthma and rhinoconjunctivitis, adjusting for correlated fats (saturated, monounsaturated, omega-6 and omega-3 polyunsaturated) and other covariates. For mechanistic insights, murine models of aeroallergen-induced allergic airway inflammation (AAI) fed with a low-fat-high-sucrose or -high-starch versus a high-fat diet were used to characterize and quantify disease development. Metabolic and physiologic parameters were used to track outcomes of dietary interventions and cellular and molecular responses to monitor the development of AAI. Oxidative stress biomarkers were measured in murine sera or lung homogenates.

RESULTS

We demonstrate a direct association of dietary sucrose with asthma prevalence in males, while starch was associated with higher asthma prevalence in females. In mice, high-carbohydrate feeding, despite scant metabolic effects, aggravated AAI compared to high-fat in both sexes, as displayed by humoral response, mucus hypersecretion, lung inflammatory cell infiltration and T_H 2-T_H 17 profiles. Compared to high-fat, high-carbohydrate intake was associated with increased pulmonary oxidative stress, signals of metabolic switch to glycolysis and decreased systemic anti-oxidative capacity.

CONCLUSION

High consumption of digestible carbohydrates is associated with an increased prevalence of asthma in humans and aggravated lung allergic inflammation in mice, involving oxidative stress-related mechanisms.

The role of short-term grass pollen exposure in food skin-prick test reactivity, food allergy, and eczema flares in children

BACKGROUND

While the relationship between pollen and respiratory allergies is well-documented, the role of short-term pollen exposure in food allergy and eczema flares has not previously been explored. We aimed to investigate these associations in a population-based sample of children.

METHODS

We investigated 1- (n = 1108) and 6-year-old (n = 675) children in the grass pollen season from the HealthNuts cohort. Grass pollen concentrations were considered on the day of testing (lag 0), up to three days before (lag 1-lag 3) and cumulatively (lag 0-3). Associations between grass pollen and food skin-prick test reactivity (SPT ≥ 2 mm at age 1 year and ≥ 3 mm at age 6 years), eczema flares, challenge-confirmed food allergy, reaction threshold to oral food challenges (OFC), and serum food-specific IgE levels were analyzed using either logistic or quantile regression models. Atopy and family history of allergic disease were considered as potent effect modifiers.

RESULTS

Grass pollen at lag 0-3 (every 20 grains/m³ increase) was associated with an up to 1.2-fold increased odds of food SPT reactivity and eczema flares in 6-year-olds. In 1-year-olds, the associations were only observed for peanut in those with a family history of food allergy. Increasing grass pollen concentrations were associated with a lower reaction threshold to OFC and higher serum IgE levels in peanut-allergic 1-year-olds only.

CONCLUSION

Increasing grass pollen concentration was associated with increased risk of food SPT reactivity and eczema flares in children. The associations in peanut-allergic infants may be related to immune activation and/or peanut and grass pollen cross-reactivity leading to a lower reaction threshold.

Sensitisation to Pollen Allergens in Children and Adolescents of Different Ancestry Born and Living in the Same Area

Background

Allergy can start at early ages, with genetic and environmental factors contributing to its development.

Aim

The study aimed to describe the pattern of sensitisation and allergy in children and adolescents of Spanish versus Moroccan ancestry but born in the same rural area of Spain.

Methods

Participants were children and adolescents (3–19 years) of Spanish or Moroccan descent, born in Blanca, Murcia (Spain). A detailed questionnaire was completed, and skin prick tests were performed to assess reactions to the most prevalent pollen allergens (O. europaea, P. pratense, S. kali, C. arizonica, P. acerifolia, A. vulgaris and P. judaica) plus molecular components Ole e 1 and Ole e 7. The association with ancestry was verified by studying participants’ parents.

Results

The study included 693 participants: 48% were aged 3–9 years and 52%, 10–19 years; 80% were of Spanish descent and 20% of Moroccan descent. Sensitisation to Olea europaea, Phleum pratense, Salsola kali and Cupressus arizonica were slightly higher in the Spanish group. The only significant differences were observed in sensitisation to Ole e 1 (p=0.02). Rhinitis, conjunctivitis, and rhinitis plus asthma were significantly higher in the Spanish group (p=0.03, p=0.02, p=0.007, respectively). The sensitisation pattern differed between Spanish and Moroccan parents, and between Moroccan parents and their children, but not between Spanish parents and their children.

Conclusion

Both environment and ancestry may influence sensitisation and symptoms. Although the environment seems to have a stronger influence, other factors may contribute to the differences in prevalence and in the clinical entities in people of Spanish versus Moroccan descent.

Sensitisation to Imbrasia belina (mopane worm) and other local allergens in rural Gwanda district of Zimbabwe

Background

The prevalence of allergic diseases is increasing in Zimbabwe and the data relate to local as well as exotic allergen sources. As entomophagy, the practice of eating insects, is a recognised source of local allergens, we sought to measure the prevalence of and risk factors for sensitisation to Imbrasia belina (mopane worm), a popular edible insect. This was investigated alongside other locally relevant allergens in a rural community in Gwanda district, south of Zimbabwe.

Methods

A cross sectional study was conducted among 496 adults and children aged 10 years and above in Gwanda district, a mopane worm harvesting area in Zimbabwe. Data on individual characteristics and mopane worm exposure factors were collected using questionnaires. Sensitivity to allergens was assessed by performing skin prick tests at a local clinic using 10 different commercial allergen extracts (Stallergenes, France) and in-house extracts of mopane worm (Imbrasia belina) and mopane leaves (Colophospermum mopane). Data were analysed using Stata version 13 software.

Results

The prevalence of sensitisation to at least one allergen was 31.17% (n = 144). The prevalence of atopy was higher in adults (33.33%) than in children (23.53%) (p = 0.059). The commonest inhalant allergen sources were mopane worm (14.29%), Tyrophagus putrescentiae (14.29%), mopane leaves (13.42%), Alternaria alternata (6.49%) and Dermatophagoides pteronyssinus (6.49%). Polysensitisation was demonstrated in the study population and of the 108 participants (75%) who were sensitised to two or more allergens, 66 (61%) were women. Sensitisation to mopane worm and mopane leaves often clustered with Tyrophagus putrescentiae amongst adults. Adjusted logistic regression analyses between mopane worm sensitisation and self-reported exposure variables showed that sensitisation was more likely amongst mopane worm harvesters (OR = 1.92, 95%CI = 0.77–4.79), those who cooked or roasted mopane worms during harvesting (OR = 2.69, 95%CI = 0.78–9.31) and harvesting without personal protective equipment (PPE) (OR = 2.12, 95%CI = 0.83–5.44) compared to non-harvesters.

Conclusion

Atopic sensitization was common in this mopane worm harvesting community in Gwanda district of Zimbabwe. There was frequent co-sensitisation of mopane worm and mopane leaves with Tyrophagus putrescentiae in children and adults. It is important to determine the clinical relevance of our findings, particularly relating to mopane worm sensitisation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13223-022-00668-0.

Sex-specific developmental trajectories of eczema from infancy to age 26 years: A birth cohort study

BACKGROUND

Eczema is a common inflammatory skin disease with varying developmental trajectories/patterns that are influenced by different risk factors. The aim of this study was to investigate eczema development from infancy to early adulthood by identifying distinct developmental trajectories that describe disease patterns over time and evaluate the role of prenatal and early-life risk factors.

METHODS

The Isle of Wight Birth Cohort (n = 1456) was prospectively assessed at birth, 1, 2, 4, 10, 18 and 26 years. In all assessments, eczema was defined as chronic or chronically relapsing itchy dermatitis lasting >6 weeks with characteristic morphology and distribution in the past 12 months. Developmental trajectories of eczema between 1 or 2 and 26 years were identified separately for males and females by applying semiparametric mixture models. Associations were assessed by applying a modified Poisson regression to estimate adjusted risk ratios (aRR) and 95% confidence intervals (CI).

RESULTS

In both males and females, the following eczema developmental trajectories were identified: unaffected/transient (males: 77.7% vs. females: 73.0%), mid-onset late-resolving (males: 7.8% vs. females: 4.4%), late-onset (males: 5.2% vs. females: 9.5%) and early-onset persistent (males: 9.3% vs. females: 5.4%). In females, an additional trajectory was identified as follows: early-onset early-resolving (7.7%). Among males, filaggrin gene (FLG) variants (aRR = 2.45, 95% CI: 1.34-4.46) and paternal eczema (2.66, 1.39-5.08) were associated with the early-onset persistent trajectory. Among females, maternal eczema (2.84, 1.42-5.70) and high birthweight (2.25, 1.08-4.69) were associated with the early-onset persistent trajectory.

CONCLUSIONS

Four and five trajectories represented eczema development among males and females, respectively, with different predisposing risk factors. Our results indicate that males and females may experience a different course of eczema.

The Effect of Allergen Immunotherapy on the Development of New Sensitization in Children

Aim

The protective effect of allergen immunotherapy against a new allergic sensitization is controversial. This study aimed to investigate the effect of allergen immunotherapy on new allergic sensitization in children.

Materials and Methods

The study included 50 patients who received immunotherapy for at least 3 years, and whose skin prick tests were repeated at intervals of at least 3 years (31 patients for house dust mite immunotherapy, 19 patients for pollen immunotherapy), and 69 controls with similar characteristics.

Results

The number of patients who developed a new sensitization was similar both in the groups of patients who received house dust mite and pollen immunotherapy, and the control group. There was no significant difference between the first and last skin prick tests of the patients who received house dust mite and pollen immunotherapy; however, in the control groups, a significant increase in sensitivity to tree pollens (n = 2, 5.4%; n = 8, 21.6%) and weed pollens (n = 7, 26.9%; n = 14, 53.8%) was detected (P = .031 and P = .039). While allergen sensitivities in the first tests of the pollen immunotherapy group and the control group were similar, weed pollen sensitivity was significantly higher in the last tests of the control group (n = 14, 53.8%; n = 4, 21.1%, P = .027). It was determined that the presence of weed pollen sensitization (OR: 8.1, 95% CI: 1.5-42.4) and having asthma (OR: 3.5, 95% CI: 1.3-10.8) increases the risk of new sensitization in all groups.

Conclusion

Allergen immunotherapy has been found to protect against new sensitization to tree and weed pollens. However, this effect was insignificant in the multivariate analysis. Weed pollen sensitization and the presence of asthma are related to the development of new sensitization.

Maternal prenatal psychological distress associates with offspring early-life wheezing - FinnBrain Birth Cohort

BACKGROUND

Exposure to prenatal maternal psychological distress may contribute to the development of childhood atopic disorders. Little is known about the importance of distress severity and its duration for the risk. Our aim was to investigate how chronic maternal depressive and anxiety symptoms across gestation influence the risk of wheezing and eczema at child age 24 months.

METHODS

The study population was drawn from the FinnBrain Birth Cohort Study, including 1305 mother-infant dyads followed across gestation until the child age of 24 months when the outcomes were mother-reported wheezing ever and doctor-diagnosed eczema. To investigate the risk of wheezing phenotypes, wheezing with and without eczema was separated. Maternal distress was assessed with the Edinburgh Postnatal Depression Scale for depressive and the Symptom Checklist-90 for anxiety symptoms three times during pregnancy, and the chronicity was demonstrated using symptom trajectories composed by latent growth mixture modeling.

RESULTS

Of the children, 219/1305 (17%) had wheezing ever and 285/1276 (22%) had eczema. Risk of wheezing ever was elevated with maternal consistently high depressive symptoms (adjusted odds ratio 2.74; 95% confidence interval 1.37-5.50) or moderate and increasing anxiety symptoms (1.94; 1.06-3.54, respectively). Similarly, wheezing without eczema was associated with consistently high depressive (3.60; 1.63-7.94, respectively) and moderate and increasing anxiety symptoms (2.43; 1.21-4.91, respectively).

CONCLUSIONS

Maternal chronic psychological distress across gestation was associated with toddler wheezing and especially wheezing without other atopic features (eczema). This finding supports the theory of intrauterine programming effect by maternal psychological distress on offspring immune system and respiratory morbidity.

Prevalence of inhaled allergen-specific IgE antibody positivity in the healthy Japanese population

BACKGROUND

Measurement of allergen-specific IgE antibodies to inhaled allergens is important for the diagnosis and risk evaluation of allergic diseases such as asthma and allergic rhinitis. This study aimed to elucidate the prevalence of allergen sensitization among the healthy population in Japan using serum samples stocked in the Japanese Red Cross for blood donation.

METHODS

Age- and gender-stratified serum samples (n = 800) from residents in Tokyo aged 20-59 years were randomly selected from the stocked serum obtained for blood donation in 2005. Total and specific IgE antibodies to 17 inhaled allergens were measured by the ImmunoCAP method. Individuals with positive (≥0.35 U_A/mL) specific IgE antibodies to at least one inhaled allergen were defined as atopic. Stocked serums from donors aged 20-29 years in Sapporo, Osaka, Fukuoka, and Okinawa (n = 200 each) were also obtained for the measurement of IgE to six common inhaled allergens, to evaluate regional differences in the rate of positivity.

RESULTS

Among residents in Tokyo, the prevalence of atopy was 78.0% and highest in men aged 20-29 years (94.0%), which decreased with age. The prevalence of specific IgE antibodies was highest for Japanese cedar pollen (66.8%), followed by cypress pollen (46.8%), Dermatophagoides pteronyssinus (38.3%), and moths (30.1%). Examination of IgE to Japanese cedar pollen, D. pteronyssinus, and moths identified 97.6% of atopic subjects in Tokyo. There were substantial regional differences in the prevalence of pollen IgE positivity.

CONCLUSIONS

This study demonstrated an extremely high prevalence of positivity in inhaled allergen-specific IgE antibodies among healthy adults in Japan.

The effect of recombinant human interferon α1b treatment of infants hospitalized with lower respiratory tract infection on subsequent wheezing

OBJECTIVE

To investigate the impact of recombinant human interferon α1b (rhIFNα1b) treatment in infants hospitalized with lower respiratory tract infections on subsequent wheezing.

METHODS

The clinical data of infants (n=540) with viral pneumonia, wheezy bronchitis, or bronchiolitis hospitalized in 19 Chinese hospitals from June 2009 to June 2015 were retrospectively analyzed. The parameters relevant to wheezing episodes within the last year were collected by telephone and questionnaires. The rhIFNα1b treatment group (n=253) and control group (n=287) were compared in terms of wheezing episodes within the last year. Moreover, the wheezing group (95 cases) and non-wheezing group (445 cases) were compared.

RESULTS

Out of 540 cases, 95 (17.6%) experienced wheezing episodes, 13.8% (35/253) cases treated with rhIFNα1b, and 20.9% (60/287) cases without rhIFNα1b experienced wheezing episodes within the last year. The rhIFNα1b treatment significantly improved wheezing episodes within the last year, compared with the control peers (p=0.031). Single-factor regression showed statistically significant differences between the wheezing and non-wheezing groups in terms of age, rhIFNα1b use, childhood and family history of allergy, housing situation, and feeding history (p<0.05). Binary logistic regression showed a childhood history of allergy (OR=2.14, p=0.004), no rhIFNα1b use (OR=1.70, p=0.028), and living in a crowded house (OR=1.92, p=0.012) might be risk factors of subsequent wheezing. Accordingly, breastfeeding (OR=0.44, p=0.008) and hospitalization age of ≤1-year-old (OR=0.58, p=0.024) were protective factors.

CONCLUSIONS

Early use of rhIFNα1b in infants hospitalized with lower respiratory tract infections and breastfeeding could prevent subsequent wheezing. Living in a crowded house could promote subsequent wheezing.

The majority of children sensitized before school-age develop allergic disease before adulthood: a longitudinal population-based study

BACKGROUND

Allergic sensitization increases the risk of and asthma and allergic rhinitis, but the impact of age at onset of sensitization is less studied.

OBJECTIVE

To examine the cumulative incidence of asthma and rhinitis up to age 19 years in relation to age at onset of sensitization to airborne allergens.

METHOD

All children in grade one and two (median age 8 years) in two municipalities in Northern Sweden were invited to skin prick tests and a questionnaire about allergic diseases, and 88% participated. At ages 12 and 19 years the protocol was repeated, and n=1510 individuals participated in all three examinations. Specific IgE was collected in a random sample at age 19, n=770. Onset of sensitization was defined; ≤8 years, 8-12 years, 12-19 years, and never sensitized. Adjusted Poisson regression was utilized to calculate risk ratios.

RESULTS

At age 19, those sensitized ≤8 year had the highest risk of asthma (RR 4.68 (95%CI 3.14-6.97)) and rhinitis (RR 22.3 (95%CI 13.3-37.6)), and 84% had developed either asthma or rhinitis. The combination of sensitization ≤8 year and family history of allergic diseases rendered high risks for asthma (RR 10.6 (6.71-16.7)) and rhinitis (RR 36.3 (18.9-69.7). Individuals sensitized ≤8 year showed significantly highest level of sensitization, as judged by number of positive skin tests and titers of specific IgE.

CONCLUSION

The majority of individuals with sensitization ≤8 years developed asthma or rhinitis before young adulthood. The high level of sensitization in early sensitized contribute to the high incidence of allergic airway conditions.

Atopic Dermatitis: Epidemiology and Clinical Phenotypes

Atopic dermatitis (AD) is a chronic, lifelong, relapsing condition. The wide spectrum of the possible clinical presentations, depending on patient' s age, age of onset of disease, topography and morphology of dermatitis, limits the epidemiologic information on its prevalence and incidence. A clear definition of the different clinical AD phenotypes and epidemiology is essential for an appropriate patient's treatment and management, in particular for adults. This review summarizes the most recent epidemiologic data from the 21^st century, on AD prevalence and incidence rates either in children or adults, with a special focus on their trends in Europe. Moreover, an effort to categorize diverse AD clinical expressions, has been made, aiming to facilitate differential diagnosis and speed up the start of the correct therapy.

One march, many paths: Insights into allergic march trajectories

OBJECTIVE

The classical allergic march model posits that atopy begins in infancy with atopic dermatitis and progresses to asthma and allergic rhinitis in a subset of individuals. The growing prevalence and severity of allergic diseases have prompted renewed interest in refining this model. This review outlines epidemiologic evidence for the existence of allergic march trajectories (distinct paths of atopy development in individuals); reviews the roles that genetics, environment, and disease endotypes play in determining trajectory outcomes; and discusses the clinical utility of the trajectory model.

DATA SOURCES

PubMed search of English-language articles and reviews without date limits pertaining to the epidemiology, genetics, and immunologic mechanisms of allergic march trajectories and disease endotypes.

STUDY SELECTIONS

Studies and reviews were selected based on their high quality and direct relevance to the review topic.

RESULTS

Recent work in the field has revealed that immunoglobulin E-mediated food allergy and eosinophilic esophagitis are components of the allergic march. Furthermore, the field is acknowledging that variability exists in the number and sequence of allergic manifestations that individuals develop. These allergic march pathways, or trajectories, are influenced by genetic, environmental, and psychosocial factors that are incompletely understood.

CONCLUSION

Continued elucidation of the landscape and origins of allergic march trajectories will inform efforts to personalize allergic disease prevention, diagnosis, and treatment.

Prenatal heavy metal exposure, total immunoglobulin E, trajectory, and atopic diseases: A 15-year follow-up study of a Taiwanese birth cohort

Prenatal exposure to heavy metals may cause atopic diseases. Little association between cord blood total immunoglobulin E (CB-tIgE) levels and the occurrence of atopic diseases has been found. This study investigated the atopic status and tIgE trajectory trend in a Taiwanese birth cohort over 15 years. We also assessed the effect of maternal heavy metal exposure on maternal serum cytokine and CB-tIgE levels. We recruited 430 pregnant women during their third trimester in 2000-2001. Maternal urinary heavy metal concentrations and serum cytokine levels were measured. The CB-tIgE and serum tIgE levels of the women's children when they were aged 5, 8, 11, and 14 years were measured. The upper quartile of the maternal urinary arsenic concentration was associated with an increased risk of a CB-tIgE level higher than 1 IU/mL (odds ratio, 1.845; 95% confidence interval, 1.003-3.395). Serum tIgE trajectory levels were the highest in children with asthma, followed by those with atopic dermatitis and allergic rhinitis at the age of 5-14 years. Serum tIgE levels tended to peak at the age of 11 years in the atopic children but were stable from the age of 8 years in the non-atopic children. We first demonstrated that serum tIgE levels reached a trajectory peak in the atopic children aged 11 years. Prenatal exposure to arsenic may increase the risk of elevated CB-tIgE levels. Further investigation is warranted to elucidate the mechanism through which maternal serum cytokines affect the occurrence of atopic diseases in children.

Early-life environmental exposures associate with individual and cumulative allergic morbidity

Several early-life environmental factors have been associated with altered risk for the development and/or severity of individual allergic conditions. These include exposures implicated in the modulation of the microbiome, such as infant delivery mode, diet, and exposure to antibiotics and antacids. The impact of these early-life factors on allergic multimorbidity remains unknown. To address this knowledge gap, we used electronic medical records for a birth cohort of 158,510 children to track development of atopic dermatitis (AD), IgE-mediated food allergy (IgE-FA), asthma, and allergic rhinitis (AR) in individual children over time. We measured hazard ratios (HRs), adjusted for birth year, race, ethnicity, sex, and insurance payer type, to assess how development of both individual and multiple allergic conditions is influenced by birth mode, feeding practice during the first year of life, or exposure to antibiotics and/or antacids during the first six months of life. We found that vaginal delivery (VD; HR 0.89, 0.83, 0.84, 0.79 for at least 1, 2, 3, 4 conditions, respectively; p≤0.001) and exclusive breastmilk (BM) feeding (HR 0.74, 0.75, 0.89, for at least 1, 2, 3 conditions, respectively; p≤0.001) are associated with reduced cumulative allergic burden, while antibiotic exposure (HR 1.40, 1.44, 1.48, 1.63 for at least 1, 2, 3, 4 conditions, respectively; p≤0.001) and antacid exposure (HR 1.26, 1.35, 1.32 for at least 1, 2, 3 conditions, respectively; p≤0.001) are associated with increased cumulative allergic burden during childhood. This work expands our understanding of how a child’s early-life environment may influence their risk of allergy development and progression.

The natural course of cow's milk allergy and the development of atopic diseases into adulthood

BACKGROUND

Previous studies have investigated the natural course of cow's milk allergy (CMA) and development of atopic diseases into adolescence. Studies with long-term follow-up into adulthood are lacking. The aim of this study was to investigate (a) the natural course of CMA in a 1-year birth cohort of Danish children from birth until 15 and 26 years of age and (b) the development of atopic diseases in a group of children with CMA (group A) compared to a random sample of 276 children from the same birth cohort (group B).

METHODS

A birth cohort of 1749 newborns was investigated prospectively for the development of CMA and atopic diseases. During the first year of life and at 18 months and 3, 5, 10, 15, and 26 years of age, questionnaire-based interviews, physical examination, skin prick tests, and specific IgE testing, and from 10 years also spirometry, were carried out.

RESULTS

Thirty-nine (2.2%) were diagnosed with CMA. The recovery rate was 87%, 92%, and 97% at 3, 5, and 26 years of age. Compared to group B, group A had significantly (P < .05) higher prevalence of asthma and rhinoconjunctivitis at 15 years of age, and at 26 years of age, group A had significantly higher prevalence of asthma and atopic dermatitis. The follow-up rate was 85% (A) and 70% (B).

CONCLUSION

CMA has a good prognosis regarding recovery rate. However, CMA, especially IgE-mediated, in early childhood predicts a high prevalence of atopic diseases into adulthood.

Effects of hypersensitivity disorders and environmental factors on the equine intestinal microbiota

Background

Recent evidence suggests that an altered intestinal microbiota, specifically a reduction of bacterial diversity or a shift in microbial composition, is associated with the development of hypersensitivity disorders in humans, but this is unknown for horses.

Objectives

In this study we hypothesized that horses affected by either Culicoides hypersensitivity or severe equine asthma or both show a decreased diversity of their intestinal microbiota. We also investigated environmental effects.

Methods

Rectal swab samples of a total of 140 horses were collected and the owners completed a detailed questionnaire about their horse. For each allergic horse, a healthy peer from the same stable was equally sampled as an environmentally matched control. Microbiota in the swabs was determined by assessing the V4 region of the bacterial 16S rRNA gene. Structures of bacterial communities were investigated by means of alpha and beta diversity indices.

Results

Group wise comparisons between healthy and allergic horses showed no significant differences regarding alpha (p = 0.9) and beta diversity (p = 0.5). However, the microbial structure was associated with environmental factors such as the type of stable (p = 0.001), access to pasture (p = 0.001) or the type of feeding (p = 0.003). There was also a strong location effect meaning that the microbiota was more similar within the same as compared between farms within this study.

Conclusion

Our observations suggest that hypersensitivity disorders in adult horses are not associated with an alteration of the intestinal microbiota, but environmental and/or location factors strongly influence these bacteria.

Incidence and remission of aeroallergen sensitization in adults in Northern Finland: 15 years longitudinal study

Studies on the longitudinal changes in sensitization to aeroallergens in adult populations are sparse. The aim was to evaluate changes in sensitization to aeroallergens [birch, timothy, cat and house dust mite (HDM)] in an unselected adult population aged from 31 to 46 years. Data were gathered from a cohort of adults (Northern Finland Birth Cohort 1966) who had been skin prick tested (SPT) with birch, timothy, cat and HDM allergens at the age of 31 years and at age 46 (n = 5484 and 5373 respectively). Data from both time points were available for 3409 participants, who made up the cohort of the longitudinal study. The overall prevalence of sensitization to any of the selected allergens was 30.3% (n = 1661) in 31-year-olds and 30.7% (n = 1649) in 46-year-olds. In general, men were more sensitized (P < 0.001) and also had more polysensitization (P < 0.001) compared to women. In longitudinal sub-population incidence of sensitization was 7.1%. Birch was the most prevalent new sensitizer, however, the difference was not statistically significant when compared to cat. We conclude that new sensitization, demonstrated by positive findings in SPT, can still occur in middle age and this should be taken into account when managing allergic manifestations in adults as sensitization can be considered the first step in developing clinical allergy.

Current status of fecal calprotectin as a diagnostic or monitoring biomarker for cow's milk protein allergy in children: a scoping review

BACKGROUND

There are few approved biomarkers for diagnosis and monitoring of cow's milk protein allergy (CMPA), thus the oral food challenge remains to be the golden diagnostic standard. A potential biomarker is fecal calprotectin, a cytosolic protein, elevating in the presence of intestinal mucosal inflammation. We aimed to undertake a scoping review of the evidence pertaining to the current status of fecal calprotectin used for diagnosis and monitoring CMPA in children, and tried to indicate the aspects needed to be concerned in the future investigations and researches.

METHODS

A scoping review was performed using the literature searched from PUBMED, EMBASE, and Web of Science Databases until July 2019 on the studies about the application of fecal calprotectin as a biomarker of CMPA in children. Studies were examined according to the inclusion and exclusion criteria. Data were extracted, and a narrative synthesis was conducted to summarize and analyze.

RESULTS

Thirteen studies with different study design embracing 1238 children were included. The age range was from infants to adolescents. Most children with CMPA presented gastrointestinal symptoms, among which hematochezia was most common. Amount of data suggested that infants with CMPA represented elevated levels of fecal calprotectin, particularly with distinct significance in non-IgE-mediated CMPA groups. Decreases of fecal calprotectin after elimination diet were demonstrated in enrolled studies. However, no matter in the CMPA positive or negative groups, the changes of fecal calprotectin before or after challenge showed no significance. Contradictory results were generated from studies on the role of fecal calprotectin in predicting allergic disease.

CONCLUSIONS

Available evidence is not sufficient to confirm the utilization of fecal calprotectin both in diagnosis and monitoring of CMPA and predicting for allergic disease. More clinical and bench researches with elaborate design should be conducted and the exact cut-off values of fecal calprotectin in different groups remain to be determined.

The triad of current asthma, rhinitis and eczema is uncommon among adults: Prevalence, sensitization profiles, and risk factors

BACKGROUND

Coexistence of asthma, rhinitis, and eczema has been studied in children, but data are lacking in adults. As new treatments emerge, epidemiological data on the coexistence are needed.

AIMS

To study the prevalence of concomitant asthma, rhinitis and eczema in the general adult population and among those sensitized to aeroallergens, and to study associations between background characteristics and risks of phenotypes of asthma, rhinitis, and eczema.

METHODS

In the West Sweden Asthma Study, phenotypes and sensitization profiles of 1103 randomly selected adults (16-75 years) were assessed. The methods included measures of serum-IgE and structured interviews on asthma, rhinitis, eczema, their associated symptoms, and relevant risk factors.

RESULTS

Among all participants and in those sensitized, 2% and 6% had concomitant asthma, rhinitis, and eczema, respectively, and the condition did not differ by age or sex. Corresponding figures for asthma and rhinitis, but not eczema, was 8% and 19%, respectively. Determinants of coexistence of the three conditions were family history of asthma/allergy, body mass index, and occupational exposure to gas, dust and fumes. Allergic sensitization in those with asthma, rhinitis and eczema was found in 78%, in those with asthma and rhinitis but not eczema in 65%, in those with asthma and eczema but not rhinitis in 40%, while only 5% were sensitized among those having asthma only.

CONCLUSIONS

In the general adult population about 2% have concomitant asthma, rhinitis, and eczema. Of sensitized adults, about 6% has coexistence of the three conditions.

[Effect of maternal immune level at different pregnancy stages on cow's milk protein allergy in infants]

OBJECTIVE

To study the association between maternal Th1/Th2 immune level at different pregnancy stages and cow's milk protein allergy (CMPA) in infants.

METHODS

The healthy women with a singleton pregnancy, as well as their offspring, who attended Yidu Central Hospital of Weifang and Qingzhou Traditional Chinese Medicine Hospital from July 2016 to December 2018 were enrolled. The maternal levels of interleukin-2 (IL-2), interferon gamma (IFN-γ), interleukin-4 (IL-4), and interleukin-10 (IL-10) at the second and third trimesters of pregnancy were measured. A CMPA questionnaire survey was conducted within one year after birth. Food avoidance and cow's milk oral challenge tests were performed in infants suspected of CMPA. The 48 infants who met the diagnostic criteria for CMPA were included in the observation group, and the remaining 977 normal infants were included in the control group. A univariate analysis was performed on the infants with CMPA. A Poisson regression analysis was used to determine the association between maternal Th1/Th2 immune factors at different pregnancy stages and CMPA.

RESULTS

The detection rate of CMPA was 4.68%. The clinical manifestations included the symptoms of the digestive system, skin, and respiratory system and other symptoms. The univariate analysis showed that compared with the control group, the observation group had significantly higher incidence rates of maternal food allergy and maternal history of allergic diseases (P<0.05) and a significantly lower breastfeeding rate (P<0.05). The observation group had significantly lower maternal levels of IL-2 (second and third trimesters) and IFN-γ (third trimester) than the control group (P<0.05). Maternal low IFN-γ at the third trimester and maternal low IL-2 at the second and third trimesters were significantly associated with CMPA in infants (P<0.05). After correction of the factors of breastfeeding, maternal food allergy, and maternal history of allergic diseases, it was found that maternal low IL-2 and IFN-γ at the third trimester were still significantly associated with CMPA in infants (P<0.05).

CONCLUSIONS

The maternal decrease in Th1 level at the third trimester of pregnancy may lead to the change in fetal immunity and thus increase the risk of CMPA in offspring.

Male sex is strongly associated with IgE-sensitization to airborne but not food allergens: results up to age 24 years from the BAMSE birth cohort

Background

Up to half of the population in high-income countries has allergen-specific IgE antibodies. However, data regarding sex differences of IgE-sensitization from childhood to adulthood is limited.

Objective

To explore IgE-sensitization to common foods and airborne allergens in relation to sex over time in a population-based cohort followed up to young adulthood.

Methods

The Swedish population-based birth cohort BAMSE includes 4089 subjects who have been followed regularly with questionnaires and clinical investigations. A recent 24-year follow-up included 3069 participants (75%). Sera collected at 4, 8, 16 and 24 years were analyzed for IgE-antibodies to 14 common foods and airborne allergens.

Results

At 24 years sensitization to foods had decreased compared to previous follow-ups affecting 8.4%, while sensitization to airborne allergens was more common, affecting 42.2%. Male sex was associated with IgE-sensitization to airborne allergens at all ages (overall OR: 1.68, 95% CI 1.46–1.94) while there was no statistically significant association between sex and sensitization to food allergens (overall OR: 1.10, 95% CI 0.93–1.32). Levels of allergen-specific IgE did not differ significantly between males and females for any of the tested foods or airborne allergens at any age, following adjustment for multiple comparisons.

Conclusion

IgE-sensitization to airborne allergens increases with age up to young adulthood, whereas sensitization to food allergens seems to level off. Male sex is strongly associated with IgE-sensitization to airborne allergens from early childhood up to young adulthood. In contrast, there is little evidence for associations between sex and IgE-sensitization to foods.

Events in Normal Skin Promote Early-Life Atopic Dermatitis-The MPAACH Cohort

BACKGROUND

Nonlesional skin in atopic dermatitis (AD) is abnormal, but the pathobiology of lesional and nonlesional skin and the definition of endotypes are poorly understood.

OBJECTIVE

To define lesional and nonlesional endotypes of AD by building the first US-based early-life prospective cohort of children with AD, the Mechanisms of Progression from AD to Asthma in Children cohort.

METHODS

We assessed lesional and nonlesional skin transepidermal water loss, filaggrin (FLG) and alarmin (S100A8, S100A9) expression, staphylococcal colonization, and patterns of aeroallergen and food sensitization to define nonlesional and lesional phenotypes and endotypes.

RESULTS

Pathophysiologic changes were present in lesional and nonlesional skin and were associated with SCORing for Atopic Dermatitis. Nonlesional skin had features characteristic of diseased skin including low FLG and high alarmin expression, and increased colonization with Staphylococcus aureus. In a multivariate model, nonlesional, but not lesional, FLG expression was associated with the development of cosensitization and moderate to severe AD. Lesional skin was characterized by further deficits in FLG expression (P < .001), but alarmin expression was the same as observed in nonlesional skin.

CONCLUSIONS

This study reveals that events in the nonlesional, not the lesional, skin promote the subsequent development of AD severity and cosensitization, which is a key risk factor for allergic comorbidities. Collectively, these data suggest the presence of a subclinical eczema endotype that may predispose to the development of allergic disease in the absence of overt eczema. This may represent a new definition of the atopic march that starts with skin barrier dysfunction rather than eczema.

Approach to the Assessment and Management of Pediatric Patients with Atopic Dermatitis: A Consensus Document. Section II: Comorbid Disease in Pediatric Atopic Dermatitis

Pediatric atopic dermatitis (AD) is one of the most common skin conditions encountered by health-care providers caring for infants, children, and adolescents. Pediatric patients with AD may present with other allergic and nonallergic comorbidities that require appropriate treatment and referral. They may also experience a trajectory of allergic diseases known as the atopic march, which depends on a complex interaction between genetic and environmental factors and likely involves early epidermal barrier dysfunction. Here we provide a review and clinical recommendations on the assessment and referral of comorbidities in pediatric AD.

Disease trajectories in childhood atopic dermatitis: an update and practitioner's guide

BACKGROUND

Atopic dermatitis (AD) is a heterogeneous disease with a multifactorial aetiology and complex pathophysiology. This heterogeneity translates into different trajectories of disease progression with respect to severity, persistence and risk of development of atopic comorbidities. Determining which possible disease trajectories or comorbidities any individual child might develop is challenging in clinical practice. Tools that help identify paediatric patients at higher risk of disease progression would greatly aid clinicians.

METHODS

We reviewed recent cohort studies to synthesize and simplify the epidemiological data to try to identify shared clinically relevant characteristics that may help physicians estimate the risk of disease progression in paediatric patients with AD.

RESULTS

Despite the variability in data collection and methods of analysis and their limitations, there are common patterns of early-childhood AD that may aid in the estimation of risk for disease progression. Factors associated with risk of AD progression include younger age of onset, family history of atopy, greater AD severity, filaggrin mutations, urban environment and polysensitization and/or allergic multimorbidity. Based on these factors, we provide a practitioner's guide for identifying, counselling and/or referring infants and children with AD at potentially higher risk of developing persistent AD and atopic comorbidities. We also present clinical scenarios to illustrate how these data relate to real-life situations.

CONCLUSIONS

Useful insights are provided for physicians and patients to inform them better about the risk of AD progression and to help guide care pathways for the paediatric population with AD. What's already known about this topic? The complex pathophysiology of atopic dermatitis (AD) translates into a heterogeneous clinical presentation and trajectories of disease progression. Although the consensus is that most paediatric patients with AD will eventually 'outgrow' the disease or follow the longitudinal trajectory known as the 'atopic march', a significant proportion will develop persistent AD and/or other atopic conditions. No known factors conclusively predict the risk of progression or development of comorbidities. What does this study add? Recent analyses of data from large cohorts of paediatric patients with AD have suggested the existence of potentially discrete clusters of patients who present with relatively common AD phenotypes. These studies have shed some light onto the factors associated with risk of progression, which we review in this article. A practitioner's guide with clinical scenarios is provided to help identify patients at high risk of progression to determine whether a patient should be monitored and/or would require specialist referral.

Keep the cat, change the care pathway: A transformational approach to managing Fel d 1, the major cat allergen

Background

Allergies to cats are the most common animal‐origin allergy, and affect approximately 1 in 5 adults worldwide. The prevalence of allergy to furry animals has been increasing, and allergy to cats is a major risk factor for the development of asthma and rhinitis. The diagnosis of cat allergy is now well established. The exact significance of component‐resolved diagnosis in the diagnosis of cat allergy remains to be fully understood. Allergen avoidance is effective but often has a psychologic impact. Allergen immunotherapy is not well demonstrated. There is a need for innovative approaches to better manage cat allergens. Next‐generation care pathways for asthma and rhinitis will define the place of cat allergen avoidance.

Methods and Results

This manuscript, based on content presented at the European Academy of Allergy and Clinical Immunology Congress 2019, provides information on the prevalence and impact of cat allergies and the molecular biology of Fel d 1, the major cat allergen.

Discussion

The authors present the scientific basis of a novel care pathway that utilizes anti‐Fel d 1 IgY antibodies to safely and effectively neutralize Fel d 1 after its production by the cat but before human exposure.

Conclusion

Efficacy of a feline diet with an egg product ingredient containing anti‐Fel d 1 IgY antibodies was demonstrated in vitro, ex vivo, and in vivo, and further validated by a pilot exposure study involving cat‐allergic human participants.

Development of a tool for screening adverse food reactions and food allergy in Portuguese children

INTRODUCTION AND OBJECTIVES

A standardised questionnaire may be an excellent tool for epidemiological studies aiming at screening children with suspected food allergies. Thus, the aim of the present study was to develop a screening questionnaire for assessing children with suspected food allergy and to analyse its reproducibility.

MATERIALS AND METHODS

A questionnaire of adverse food reactions was developed by literary review of similar questionnaires validated in other countries as well as less well defined, non-validated Portuguese questionnaires. Peer review of the questionnaire by a panel of specialists and subsequent exploratory analysis was carried out by applying the questionnaire in children with confirmed food allergy. Test-retest analysis was performed by giving a face-to-face questionnaire to 159 children with suspected adverse food reactions, aged between three and 11 years. Temporal stability using Spearman Rho correlation test and reproducibility was studied using Cohen's Kappa index.

RESULTS

115 children confirmed adverse food reactions that occurred with one or more foods. Retest was given about three weeks after the test, to 50 of these children who were randomly selected. The questionnaire showed good temporal stability (Spearman correlation coefficient of 0.834), and good reproducibility (only two of the 27 items had a Kappa index <0.60).

CONCLUSIONS

This questionnaire showed good temporal stability and reproducibility. Its validation for screening children with suspected food allergy will allow a standardised approach to diagnosis and comparison of results obtained in different centres.

Allergic sensitization among Danish infants at 13 months of age

Background

Sensitization means elevated number of specific immunoglobulin E, either measured by skin prick test or in blood samples. Sensitization is associated with, but not synonymous with, allergic disease.

Methods

The Danish Calmette Study was conducted from 2012 to 2015 at three Danish hospitals, with the aim of exploring nonspecific effects of neonatal Bacillus Calmette‐Guérin vaccination. Participants at Kolding Hospital were invited to have a blood sample analyzed for allergic sensitization at 13 months of age. Telephone interviews gave information about allergic symptoms, and the children were examined for signs of atopic dermatitis at 3 and 13 months.

Results

Of the 1241 children included in the Danish Calmette Study in Kolding 1066 (86%) had a blood sample drawn, representing 36% of the invited families. The blood sample cohort had a relatively high percentage of atopic predisposition (66.6%) and most mothers had a medium or long education. We found 90 infants (8.4%) to be sensitized, with sensitization against food items (milk, egg, peanut, and hazelnut) being the most common. Atopic dermatitis was found in 19% of the children, and it was significantly associated with sensitization against egg, peanut, wheat, cat, and dog.

Conclusion

In a partly selected Danish cohort, sensitization was present in 8% at 13 months of age, especially sensitization against food items. Children with atopic dermatitis were significantly more sensitized (16.6%). However, most sensitized children did not have any allergic symptoms at this age.

IgE sensitization in a cohort of adolescents in southern Sweden and its relation to allergic symptoms

Background

There is a strong and consistent association between IgE sensitization and allergy, wheeze, eczema and food hypersensitivity. These conditions are also found in non-sensitized humans, and sensitization is found among individuals without allergy-related diseases. The aim of this study was to analyse the sensitization profile in a representative sample of the population, and to relate patterns of allergens and allergen components to allergic symptoms.

Methods

A population of 195 adolescents took part in this clinical study, which included a self-reported questionnaire and in vitro IgE testing.

Results

Sensitization to airborne allergens was significantly more common than sensitization to food allergens, 43% vs. 14%, respectively. IgE response was significantly higher in airborne allergens among adolescents with rhinitis (p < 0.001) and eczema (p < 0.01). Among 53 children with allergic symptoms according to the questionnaire, 60% were sensitized. Sensitization to food allergens was found among those with rhinitis, but only to PR-10 proteins. None of the participants had IgE to seed storage proteins.

Conclusion

The adolescents in this study, taken from a normal Swedish population, were mainly sensitized to grass pollen and rarely to specific food allergens. The major grass pollen allergen Phl p 1 was the main sensitizer, followed by Cyn d 1 and Phl p 2. Sixty-one percent reporting any allergic symptom were sensitized, and the allergen components associated with wheeze and rhinoconjunctivitis were Fel d 4, Der f 2 and Can f 5.

Diverse age-incidence patterns of atopic sensitization in an unselected Finnish population up to 12 years

BACKGROUND

The temporal sequence in which allergic sensitization to different allergens emerges is not well characterized at the level of general population.

OBJECTIVE

We describe the incidence patterns of atopic sensitization to different allergens from birth up to 12 years of age in an unselected Finnish population.

METHODS

The study population comprised all children born between 2001 and 2006 identified from the nationwide population register as residents of the province of South Karelia, Finland (n = 5564). The results of allergy tests (22,380 results from skin prick tests, immunoglobulin E [IgE] antibodies, and open food challenges [OFCs], performed in 1827 children) were collected from patient records of all the health care units in the area.

RESULTS

The incidence rates of positive results for food and animal allergens as well as positive OFCs for cow's milk showed prominent peaks at 5 months of age. Positive results for pollen allergens started to emerge after 1.5 years of age. The 12-year cumulative incidence of sensitization to food, animal, pollen, and any allergens was 12%, 8%, 10%, and 18%, respectively. The cumulative incidence of sensitization to house dust mites was 1% and to molds or latex less than 1%. Firstborn boys had the highest, and those who were not firstborn girls and children born in rural municipalities had the lowest early incidence of sensitization to inhalation allergens.

CONCLUSION

In the unselected population, the atopic sensitization against food and animal allergens began before 6 months of age and was followed by sensitization to pollen allergens before 2 years of age. Primary prevention of sensitization to food and inhalation allergens should therefore occur in early infancy.

Atopic diseases and type I sensitization from adolescence to adulthood in an unselected population (TOACS) with focus on predictors for allergic rhinitis

BACKGROUND

While much is known on childhood atopic diseases, knowledge about persistence of atopic diseases from childhood to adulthood is limited. We therefore aimed to study the clinical course of atopic diseases and type I sensitization prospectively in an unselected cohort of adolescents followed into adulthood.

METHODS

A cohort of unselected 8th-grade school children (mean age 14 years) established in 1995 and followed up in 2010 were evaluated with questionnaire, clinical examination, skin prick tests and measurements of specific IgE.

RESULTS

The lifetime prevalence of atopic diseases was high and increased significantly from adolescence (31%) to adulthood (57%); particularly allergic rhinitis increased with an incidence rate of 17.5/1000 person-years. Childhood predictors for adult allergic rhinitis were atopic dermatitis, asthma and asymptomatic sensitization to pollen and house dust mite. Among those with asymptomatic sensitization in adolescence, 53%-78% developed allergic rhinitis in adulthood. Furthermore, type I sensitization increased significantly from adolescence to adulthood mostly due to increased sensitization to pollen. Type I sensitization was found mainly in those with allergic rhinitis. A high number of adults had oral allergy symptoms due to the high number of birch pollen allergic individuals.

CONCLUSION

Persistence of atopic diseases in adulthood is common, and a high proportion of the adult population is sensitized giving a high prevalence of allergic rhinitis. Many with asymptomatic sensitization in adolescence will develop allergic rhinitis in adult life. The focus should be on prevention of atopic diseases and sensitization already in childhood.

Relevance of low specific IgE levels to egg, milk and peanut in infancy

BACKGROUND

IgE sensitization is usually associated with allergy-related diseases, but may also occur in asymptomatic individuals. The clinical importance of IgE antibody concentrations in the interval 0.1-0.34 kU/L in early life in relation to allergy development is poorly evaluated.

OBJECTIVE

To assess the relevance of low specific IgE (s-IgE) to hen's egg, cow's milk and peanut at 6 months of age for development of sensitization and allergy-related disease during early childhood.

METHODS

s-IgE concentrations to relevant allergens from blood samples taken at 6 months and 1, 2 and 5 years from children in the prospective ALADDIN cohort were divided into three categories: non-sensitized (<0.1 kU/L), low sensitized (0.1-0.34 kU/L) and sensitized (≥0.35 kU/L) and allergy-related disease assessed.

RESULTS

A total of 372 children were included in this study. Compared with non-sensitized children at 6 months of age, children with low levels of allergen specific IgE (0.1-0.34 kU/L) to food allergens, especially to egg, at 6 months of age were associated with development of sensitization to aeroallergens at 5 years of age (10/14 [71%] vs 39/250 [15%]). In addition, children with low levels to egg or milk at 6 months were more often sensitized to the respective allergen at 1 year of age and, regarding low levels to egg, also to the development of eczema (6/18 [33%] vs 29/292 [10%]).

CONCLUSION & CLINICAL RELEVANCE

IgE antibody concentrations in the interval 0.1-0.34 kU/L to food allergens in infancy seem to increase the probability of sensitization to aeroallergens and, regarding low levels to egg, also of eczema during early childhood. Thus, IgE levels during the first year of life, although below 0.35 kU/L, can provide additional allergy-related prognostic information.

Biomarkers in Food Allergy

PURPOSE OF REVIEW

To familiarize the reader with the concept of precision medicine in food allergy by dealing with the current biomarkers for the diagnosis, prognosis, and management of the disease.

RECENT FINDINGS

Many efforts have been devoted in order to characterize reliable biomarkers able to identify specific phenotypes and endotypes in food allergy. Specific IgE (sIgE), sIgE/total IgE ratios, and T cell assays are just a few candidates that have been investigated over time. With the advent of omics sciences, a new era is commencing. A better understanding of pathogenesis of food allergy and mechanisms of action of the different therapeutic options will allow the accurate selection of the appropriate patient. In the near future, advances in technologies and data interpretation will allow a better understanding of the pathogenesis of food allergy and the identification of proper biomarkers for a personalized treatment tailored on the specific patient's profile.

Promoting and achieving excellence in the delivery of Integrated Allergy Care: the European Academy of Allergy & Clinical Immunology competencies for allied health professionals working in allergy

The multi-disciplinary team approach is an effective model for patient care. Allied health professionals (AHPs) are an important part of such teams, bringing specific knowledge and skills related to the target patient population. The AHPs most often involved in allergy care are nurses and dietitians. Nurses are often involved in the care of patients with all types of allergy and also with asthma, whilst allergy-specialist dietitians provide vital nutritional and dietary support for the diagnosis and management of food allergy. There are many other AHPs who have a role to play in allergy care, including physiotherapists, psychologists, pharmacists and speech therapists, and their involvement is likely to develop as allergy care becomes more rooted in the community. With the development of multi-professional teams comes the requirement for disease-specific knowledge and skill sets, with all allergy team members required to have baseline knowledge and competency of the condition being managed. Whilst some competencies for AHPs practising in other disease states have been published, none are available for allergic disease against which AHPs can be benchmarked. The European Academy of Allergy & Clinical Immunology (EAACI) recognised this need, and supported the establishment of a Task Force to develop allergy-focussed competencies for AHPs. The varied skills, expertise and professional background of the Task Force members enabled the creation of a set of allergy competencies relevant to all AHPs working in allergy. It is recognised that the training and allergy expertise of AHPs, and their role within the allergy setting, will vary considerably depending on the country. However, it is important for patient care, that all AHP involved in allergy services have access to training, of a sufficiently high enough level to be aspirational and enable the continued growth and development of a wide range of allergy services, given the increasing need. The EAACI competencies will provide an important benchmark for allergy knowledge and skills against which education and training can be designed and health care professionals can subsequently be measured. However, more importantly, the EAACI AHP allergy competencies will enable the development and reach of specialist allergy services, with allergy-specialist AHPs undertaking key roles, especially in the community care setting.

Prevalence of allergic sensitization, hay fever, eczema, and asthma in a longitudinal birth cohort

Purpose

The aim of this study was to longitudinally assess the prevalence of allergic sensitization, asthma, eczema and hay fever from infancy to adulthood in a single cohort.

Participants and methods

This prospective study is based on a longitudinal birth cohort of 253 participants, with respiratory and immunological assessments at 1, 6, 11, 18 and 24 years of age. Subjects were recruited from an urban maternity hospital. Retention rates varied from 45% to 72% at follow-up assessments. Asthma diagnosis was based on physician diagnosis of asthma and symptoms/medications in the previous 12 months. Allergic sensitization was defined by the positive skin prick test. Hay fever and eczema were based on a questionnaire.

Results

The prevalence of allergic sensitization rose from 19% (n=33) at 1 year of age to 71% (n=77) at 24 years of age. The rate of asthma halved from 25% at 6 years of age to 12%–15% between 11 and 24 years of age, but the prevalence of allergic sensitization among those with asthma doubled from 50% at 6 years of age to 100% at 24 years of age. Hay fever rates rose throughout childhood from 7% at 6 years of age to 44% at 24 years of age, while the prevalence of eczema reduced from 25% at 6 years of age to 16% at 24 years of age. Parental atopy doubled the odds of asthma in their offspring by 24 years of age (odds ratio [OR]= 2.63, 95% CI 1.1–6.2, p=0.029). In all, 74% of those with asthma at 24 years of age also reported hay fever. The relationship between eczema and asthma was only significant up to 11 years of age, and the relationship between hay fever and asthma was stronger in adolescence and early adulthood than in early childhood.

Conclusion

Patterns of atopic disorders vary throughout childhood. Although the prevalence of allergic sensitization and hay fever rose throughout childhood and the prevalence of asthma reduced, the strength of their relationship with asthma increased with age.

New insights into the phenotypes of atopic dermatitis linked with allergies and asthma in children: An overview

Atopic dermatitis (AD) is a complex disease with multiple causes and complex mechanistic pathways according to age of onset, severity of the illness, ethnic modifiers, response to therapy and triggers. A group of difficult-to-manage patients characterized by early-onset AD and severe lifelong disease associated with allergic asthma and/or food allergy (FA) has been identified. In this study, we focus on these severe phenotypes, analysing their links with other atopic comorbidities, and taking into account the results from recent cohort studies and meta-analyses. The main hypothesis that is currently proposed to explain the onset of allergic diseases is an epithelial barrier defect. Thus, the atopic march could correspond to an epithelial dysfunction, self-sustained by a secondary allergenic sensitization, explaining the transition from AD to allergic asthma. Furthermore, AD severity seems to be a risk factor for associated FA. Results from population-based, birth and patient cohorts show that early-onset and severe AD, male gender, parental history of asthma, and early and multiple sensitizations are risk factors leading to the atopic march and the development of asthma. The importance of environmental factors should be recognized in these high-risk children and prevention programs adapted accordingly. Effective targeted therapies to restore both barrier function and to control inflammation are necessary; early emollient therapy is an important approach to prevent AD in high-risk children. Clinicians should also keep in mind the specific risk of atopic comorbidities in case of filaggrin loss-of-function mutations and the rare phenotypes of orphan syndromes due to heritable mutations in skin barrier components.

Consideration of methods for identifying mite allergens

House dust mites are small arthropods that produce proteins—found in their feces, body parts, and eggs—that are major triggers of human allergies worldwide. The goal of this review is to describe the current methods used to identify these allergens. A literature search for allergen identification methods employed between 1995 and 2016 revealed multiple techniques that can be broadly grouped into discovery and confirmation phases. The discovery phase employs screening for mite proteins that can bind IgEs in sera from animals or patients allergic to dust mites. The confirmation phase employs biochemical methods to isolate either native or recombinant mite proteins, confirms the IgE binding of the purified allergens, and uses either in vitro or in vivo assays to demonstrate that the purified antigen can stimulate an immune response. The methods used in the two phases are defined and their strengths and weaknesses are discussed. The majority of HDM-allergic patients may respond to just a small subset of proteins, but new protein discovery methods are still warranted in order to develop a complete panel of HDM allergens for component resolved diagnosis and patient-tailored therapies.

Challenges in the implementation of the EAACI AIT guidelines: A situational analysis of current provision of allergen immunotherapy

PURPOSE

The European Academy of Allergy and Clinical Immunology (EAACI) has produced Guidelines on Allergen Immunotherapy (AIT). We sought to gauge the preparedness of primary care to participate in the delivery of AIT in Europe.

METHODS

We undertook a mixed-methods, situational analysis. This involved a purposeful literature search and two surveys: one to primary care clinicians and the other to a wider group of stakeholders across Europe.

RESULTS

The 10 papers identified all pointed out gaps or deficiencies in allergy care provision in primary care. The surveys also highlighted similar concerns, particularly in relation to concerns about lack of knowledge, skills, infrastructural weaknesses, reimbursement policies and communication with specialists as barriers to evidence-based care. Almost all countries (92%) reported the availability of AIT. In spite of that, only 28% and 44% of the countries reported the availability of guidelines for primary care physicians and specialists, respectively. Agreed pathways between specialists and primary care physicians were reported as existing in 32%-48% of countries. Reimbursement appeared to be an important barrier as AIT was only fully reimbursed in 32% of countries. Additionally, 44% of respondents considered accessibility to AIT and 36% stating patient costs were barriers.

CONCLUSIONS

Successful working with primary care providers is essential to scaling-up AIT provision in Europe, but to achieve this, the identified barriers must be overcome. Development of primary care interpretation of guidelines to aid patient selection, establishment of disease management pathways and collaboration with specialist groups are required as a matter of urgency.

The prevalence of atopic dermatitis beyond childhood: A systematic review and meta-analysis of longitudinal studies

BACKGROUND

There are sparse and conflicting data regarding the long-term clinical course of atopic dermatitis (AD). Although often described as a childhood disease, newer population-based estimates suggest the prevalence of pediatric and adult disease may be similar.

METHODS

Our objective was to determine whether there is a decline in the prevalence of AD in population-based cohorts of patients followed longitudinally beyond childhood. We conducted a systematic review and meta-analysis including studies assessing AD prevalence across 3 or more points in time. The primary outcome was weighted overall risk difference (percentage decrease in AD prevalence).

RESULTS

Of 2080 references reviewed, 7 studies with 13 515 participants were included. Participants were assessed at 3-6 time points, ranging from age 3 months to 26 years. The percentage decrease in prevalence after age 12 was 1%, which was not significantly different from zero (95% confidence interval -2%-5%). Similar results were found with other age cut-offs.

CONCLUSION

The prevalence of AD in longitudinal birth cohort studies is similar in childhood and adolescence/early adulthood.

Anaphylaxis to foods in a population of adolescents: incidence, characteristics and associated risks

BACKGROUND

Information about severe reactions to foods in adolescence is limited.

OBJECTIVE

To describe reactions to foods, including anaphylaxis, with regard to incidence, characteristics and associated risks, among 16-year-olds (adolescents) in a large, population-based birth cohort.

METHODS

Parent-reported questionnaire data from ages 2-3 months, and 1, 2 and 16 years were used (N = 3153). Anaphylaxis at age 16 years was defined per NIAID/FAAN criteria. Immunoglobulin E (IgE) antibodies to 14 common food and inhalant allergens were analysed at ages 4 (n = 2283) and 16 years (n = 2510). Among adolescents with food-related symptoms (FRS) and for whom blood was available (n = 221), 25 additional food allergen extracts or allergen components were analysed. Associations between reactions to foods, and sensitization and allergic multimorbidity were investigated.

RESULTS

In the 12 months prior to the 16-year assessment, 8.5% of adolescents had FRS. This included 0.8% (n = 24) adolescents who were classified as having anaphylaxis, yielding an incidence rate of 761/100 000 person-years. One-third of adolescents accessed health care during anaphylaxis. Allergic multimorbidity in infancy, as well as sensitization to foods and airborne allergens at age 4 years, was associated with an increased risk for FRS in adolescence. Peanuts and tree nuts were the most common culprit foods for anaphylaxis, and fruits and vegetables for non-anaphylactic reactions. Adolescents with anaphylaxis were significantly more likely to be sensitized to storage proteins (Ara h 2, Cor a 9, Cor a 14) and to be polysensitized to foods (P < 0.001 vs. non-anaphylactic reactions).

CONCLUSIONS AND CLINICAL RELEVANCE

The incidence of food-induced anaphylaxis during adolescence in our population-based birth cohort is higher than previously reported. Adolescents with anaphylaxis differ from adolescents with non-anaphylactic FRS with regard to culprit foods and sensitization. Adolescents with previous anaphylaxis are likely to be polysensitized to foods, particularly tree nut and peanut storage proteins, and which warrants consideration at follow-up.

EAACI guidelines on allergen immunotherapy: Prevention of allergy

Allergic diseases are common and frequently coexist. Allergen immunotherapy (AIT) is a disease-modifying treatment for IgE-mediated allergic disease with effects beyond cessation of AIT that may include important preventive effects. The European Academy of Allergy and Clinical Immunology (EAACI) has developed a clinical practice guideline to provide evidence-based recommendations for AIT for the prevention of (i) development of allergic comorbidities in those with established allergic diseases, (ii) development of first allergic condition, and (iii) allergic sensitization. This guideline has been developed using the Appraisal of Guidelines for Research & Evaluation (AGREE II) framework, which involved a multidisciplinary expert working group, a systematic review of the underpinning evidence, and external peer-review of draft recommendations. Our key recommendation is that a 3-year course of subcutaneous or sublingual AIT can be recommended for children and adolescents with moderate-to-severe allergic rhinitis (AR) triggered by grass/birch pollen allergy to prevent asthma for up to 2 years post-AIT in addition to its sustained effect on AR symptoms and medication. Some trial data even suggest a preventive effect on asthma symptoms and medication more than 2 years post-AIT. We need more evidence concerning AIT for prevention in individuals with AR triggered by house dust mites or other allergens and for the prevention of allergic sensitization, the first allergic disease, or for the prevention of allergic comorbidities in those with other allergic conditions. Evidence for the preventive potential of AIT as disease-modifying treatment exists but there is an urgent need for more high-quality clinical trials.

PLGA nanoparticles loaded with beta-lactoglobulin-derived peptides modulate mucosal immunity and may facilitate cow's milk allergy prevention

Beta-lactoglobulin (BLG)-derived peptides may facilitate oral tolerance to whey and prevent cow's milk allergy (CMA). Loading of BLG-peptides in poly(lactic-co-glycolic acid) (PLGA) nanoparticles (Pep-NP) may improve this. Here we studied the uptake of NP and the capacity of NP and Pep-NP to activate bone marrow dendritic cells (BMDC). Furthermore, CMA prevention was evaluated by orally exposing three-week-old female C3H/HeOuJ mice to Pep-NP, NP or free peptides (PepMix) for 6 days before oral sensitization with whole whey protein and effects on the spleen and small intestine lamina propria (SI-LP) were studied. In BMDC, NP and Pep-NP enhanced CD40 expression and IL-6 and TNF-α secretion, while tended to decrease CD80 expression and prevented PepMix-induced IL-12 secretion. In vivo, oral exposure to Pep-NP, but not NP or PepMix, prior to whey sensitization tended to partially prevent the acute allergic skin response to whole whey protein. Splenocytes of NP-pre-exposed mice secreted increased levels of whey-specific IL-6, but this was silenced in Pep-NP-pre-exposed mice which also showed reduced TNF-α and IFN-γ secretion. In the SI-LP, Pep-NP pre-exposure reduced the CD4⁺ T cell frequency in CMA mice compared to PBS pre-exposure. In addition, while NP increased whey-specific IL-6 secretion in the SI-LP, Pep-NP did not and maintained regulatory TGF-β secretion. This study presents a proof-of-concept that PLGA nanoparticles facilitate the capacity of BLG peptides to suppress the allergic response to whole whey protein. Hence, PLGA nanoparticles may be further developed as an adjunct strategy for BLG-peptide-based oral tolerance induction and CMA prevention.

Age-related changes in childhood wheezing characteristics: A whole population study

BACKGROUND

Wheezing illnesses are characterized by phenotypic variability, which changes with age, but few studies report on a wide age range of children. We studied how prevalence, severity, and triggers of wheeze vary throughout childhood.

METHODS

We analyzed data from a large population-based cohort of children from Leicestershire, UK, who were followed from infancy through late adolescence using postal questionnaires. We used generalized estimating equations to describe age-related changes in prevalence of any wheeze: episodic viral and multiple trigger wheeze; wheeze triggered by exercise, aeroallergens, food/drinks, laughing/crying; and of severe wheeze (frequent attacks, shortness of breath, sleep disturbance, disturbance of daily activities) from age 1-18 years. We analyzed this in the entire cohort (absolute prevalence) and separately among children with wheeze (relative prevalence).

RESULTS

This study included 7670 children. Current wheeze was most common in 1-year-olds (36%) and then decreased in prevalence to reach 17% in children aged 14-17 years. Absolute prevalence of episodic viral wheeze (EVW) decreased with age (from 24% to 7%), while multiple trigger wheeze (MTW) remained relatively constant throughout childhood (8-12%). Among children with wheeze, the proportion with EVW decreased, and the proportion with MTW increased with age. In older children, wheeze triggered by exercise or aeroallergens, and wheeze accompanied by shortness of breath became more frequent, while wheeze triggered by food or laughter, and sleep disturbance decreased in prevalence.

CONCLUSION

Knowledge of these age-related changes in wheezing illness is informative for health care planning and the design of future research projects and questionnaires.

Prevalence and clinical features of adverse food reactions in Portuguese children

Background

The prevalence of adverse food reactions (AFR) has been increasing in the western world. Clinical manifestations are diversified and it may not be possible to clinically discriminate between IgE and non-IgE mediated AFR. In Portugal, the prevalence of AFR and food allergies in children is not known. Thus, the objectives of this study were to determine the prevalence of AFR in central Portugal.

Methods

Point prevalence study in 3–11 year-old schoolchildren from Central Portugal. Food-related questionnaires, skin prick tests (SPT) with foods and determination of food-specific IgE levels were performed.

Results

Of 4045 schoolchildren, 2474 (61.2%) accepted to be included in the study. Global prevalence of AFR was 7.1% (95% CI 6.2–8.1), based upon the initial questionnaire, 4.6% (95% CI 3.9–5.5), based upon a confirmatory questionnaire and the prevalence of probable food allergy (IgE-associated AFR: positive history + positive SPT and/or positive specific IgE) was 1.4% (95% CI 0.9–1.9). Most frequently implicated foods were fresh fruits, fish and egg. A first episode at an earlier age, mucocutaneous and anaphylactic reactions were more frequent in IgE-associated AFR.

Conclusions

The prevalence of probable food allergy in 3–11 year old Portuguese children from central Portugal is low and parents over-report its frequency. Most frequently implicated foods were fresh fruit and fish. Immediate type, polysymptomatic, and more severe reactions may commence at an earlier age and be more frequent in IgE-associated than in non-IgE associated reactions.

Electronic supplementary material

The online version of this article (doi:10.1186/s13223-017-0212-y) contains supplementary material, which is available to authorized users.