Allergen sensitization in children with asthma and rhinitis: marked variations related to age and microgeographical factors

Impact of Fungal Spores on Asthma Prevalence and Hospitalization

Despite making up a significant proportion of airborne allergens, the relationship between fungal spores and asthma is not fully explored. Only 80 taxa of fungi have so far been observed to exacerbate respiratory presentations, with Cladosporium spp., Aspergillus spp., Penicillium spp., and Alternaria spp. found to comprise the predominant allergenic airborne spores. Fungal spores have been found in indoor environments, such as hospitals and housing due to poor ventilation. Meanwhile, outdoor fungal spores exhibit greater diversity, and higher abundance and have been associated with hospitalizations from acute asthma presentations. In addition, fungal spores may be the underlying, and perhaps the “missing link”, factor influencing the heightened rate of asthma presentations during epidemic thunderstorm asthma events. To improve our knowledge gap on fungal spores, airborne allergen monitoring must be improved to include not only dominant allergenic fungi but also provide real-time data to accurately and quickly warn the general public. Such data will help prevent future asthma exacerbations and thus save lives. In this review, we examine the health risks of prominent allergenic fungal taxa, the factors influencing spore dispersal and distribution, and why improvements should be made to current sampling methods for public health and wellbeing.

Environmental heterogeneity in human health studies. A compositional methodology for Land Use and Land cover data

The use of Land use and Land cover (LULC) data is gradually becoming more widely spread in studies relating the environment to human health. However, little research has acknowledged the compositional nature of these data. The goal of the present study is to explore, for the first time, the independent effect of eight LULC categories (agricultural land, bare land, coniferous forest, broad-leaved forest, sclerophyll forest, grassland and shrubs, urban areas, and waterbodies) on three selected common health conditions: type 2 diabetes mellitus (T2DM), asthma and anxiety, using a compositional methodological approach and leveraging observational health data of Catalonia (Spain) at area level. We fixed the risk exposure scenario using three covariates (socioeconomic status, age group, and sex). Then, we assessed the independent effect of the eight LULC categories on each health condition. Our results show that each LULC category has a distinctive effect on the three health conditions and that the three covariates clearly modify this effect. This compositional approach has yielded plausible results supported by the existing literature, highlighting the relevance of environmental heterogeneity in health studies. In this sense, we argue that different types of environment possess exclusive biotic and abiotic elements affecting distinctively on human health. We believe our contribution might help researchers approach the environment in a more multidimensional manner integrating environmental heterogeneity in the analysis.

Investigation of Allergic Sensitizations in Children With Allergic Rhinitis and/or Asthma

OBJECTIVE

Allergic rhinitis (AR) and asthma are becoming one of the most prevalent diseases in children. Identifying sensitization to aeroallergens is seemed to be valuable for diagnosing allergic disease and guiding its treatment. This study aimed to analyze the profiles of sensitization to aeroallergen in children with AR and/or asthma by skin prick test (SPT) and explore the differences of sensitization between different kinds of allergic diseases, different sexes, and different ages.

METHODS

A total of 230 children with AR and/or asthma who were hospitalized in our hospital from June 2017 to September 2019 were eligible in this retrospective study. All patients completed standardized questionnaires and SPT. Based on the sex, age, or classification of allergic disease, the sensitizations to 13 aeroallergens were compared.

RESULTS

Of the 230 patients, 67.4% of enrolled were positive for SPT; the top 5 allergens were Dermatophagoides pteronyssinus (Der.p) (59.3%), Dermatophagoides farina (Der.f ) (58.7%), Blomia tropicalis (Blot.) (40.3%), dog hair (36.1%), and Blattella germanica (20.4%). More than 90% of patients were sensitized to two or more allergens. As to the effect of age on aeroallergens, we found that the sensitizations of Blot., dog fur, and multiple sensitizations (≥5 allergens) were more common in adolescence (P < 0.01, P < 0.05). Regarding sex, we found that the positive rate of SPT and the percentages of double-allergen sensitizations in boys were much higher than girls (P < 0.01, P < 0.01), and the positive rate to Der.p, Der.f , and ragweed were also significantly higher in boys (P < 0.01, P < 0.05, and P < 0.05, respectively). Furthermore, we found that asthma-rhinitis multimorbidity increased the incidences of sensitizations; patients with AR and asthma had significantly higher positive rates to Der.p and Der.f when compared with the AR or asthma group (P < 0.05, P < 0.05).

CONCLUSION

Allergic sensitizations were common in children with AR and/or asthma; sex, age, and asthma-rhinitis multimorbidity might affect the prevalence of sensitizations to aeroallergens.

Prevalence and determinants of current asthma in Cameroon

INTRODUCTION

The prevalence of asthma varies from one country to another due to differences in ethnicity, socio-economics status, environmental and climatic risk factors. The aim of this study was to determine the prevalence and determinants of current asthma in Cameroonian adults.

MATERIAL AND METHODS

Data from 4 cross-sectional community-based studies from 2014 to 2018 were analyzed. Participants aged 19 years and above were selected through multilevel stratified random sampling methods across 2 urban areas, 2 semi-urban areas and 1 rural area. Current asthma was defined as "wheezing in the last 12 months in a subject with self-reported asthma or having used drugs for asthma treatment". Logistic regression was used to investigate the determinants of current asthma.

RESULTS

A total of 10,707 adults [median age (interquartile range)=36 (26-52) years, 44.5% of men] were definitively enrolled in the study. The overall prevalence [95% confidence interval (CI)] of current asthma was 3.9% (3.5-4.3)%. Determinants [odd's ratio (OR), (95%CI)] of current asthma were: Sudanese ethnicity [1.9(1.4-2.7)], rural area [1.5(1.1-2.1)], urban area [1.6(1.2-2.2)], past history of pneumonia [1.9(1.1-3.4)], allergic rhino-conjunctivitis [6.5(4.7-8.9)], atopic eczema [2.3(1.5-3.6)], body mass index (BMI)≥40kg/m² [1.9(1.0-3.4)] and BMI<18kg/m² [1.8(1.2-2.9)].

CONCLUSION

The prevalence of current asthma is close to the low value of the Sub-Saharan African range. Sudanese ethnicity, rural area, urban area, history of pneumonia, allergic disease, severe obesity and underweight were determinants of current asthma in Cameroon. More research is surely warranted to understand the mechanisms underlying the association of asthma with Sudanese ethnicity.

Fungi and Atopy

Atopy and fungi have a long associative history. Fungal spores were among the first substances to which humans were noted to be sensitized. Humans contact fungal spores in the outdoor, indoor, and occupational environments. As organisms, fungi have their own kingdom and are found in all environmental niches on earth. Currently, fungal exposure in the indoor environment especially related to wet housing conditions is of particular concern. Sensitization rates to fungi typically exceed 5% of the general public with higher rates among the atopic population. Alternaria is the best studied of the allergic fungi; however, cross sensitization to multiple fungi is well documented. Recent advances in understanding mechanisms of the innate immune system are beginning to explain why the fungal atopy relationship is unique and why fungal sensitivity seems to extend to many non-atopic individuals. Evidence has been accumulated that indicates fungal allergen exposure can be via intact spores as well as spore and mycelial fragments. Germinating spores produce a different and often increased allergen picture. Much evidence has been developed through animal studies that extends the mechanisms surrounding long-term low-level fungal exposure. However, it should be emphasized that the presence of fungi in the air does not necessarily equate with illness. Indeed, in the absence of an atopic individual and/or a significant immune response against fungi, there is little evidence suggesting pathology. Allergists frequently deal with patients who have concerns about indoor fungal exposure and respiratory disease in those patients with an allergic response.

Fungal Allergy: Pattern of sensitization over the past 11 years

INTRODUCTION AND OBJECTIVES

Although the prevalence of sensitization to fungi is not precisely known, it can reach 50% in inner cities and has been identified as a risk factor in the development of asthma. Whereas the prevalence of allergic diseases is increasing, it is unclear whether the same occurs with sensitization to fungi.

PATIENTS AND METHODS

A retrospective study was performed at the "Hospital Infantil de México Federico Gómez". From skin tests taken between 2004 and 2015, information was gathered about Alternaria alternata, Aspergillus fumigatus, Candida albicans, Cladosporium herbarum, Mucor mucedo and Penicillium notatum. The participating patients were 2-18 years old, presented some type of allergic condition, and underwent immediate hypersensitivity tests to the fungi herein examined. Descriptive analysis and chi-squared distribution were used.

RESULTS

Of the 8794 patients included in the study, 14% showed a negative result to the entire panel of environmental allergens. The remaining 7565 individuals displayed sensitization to at least one fungus, which most frequently was Aspergillus, with a rate of 16.8%. When the patients were divided into age groups, the same trend was observed. The highest percentage of sensitization (58%) toward at least one type of fungus was found in 2014, and the lowest percentage (49.8%) in 2008.

CONCLUSION

The rate of sensitization to at least one type of fungus was presently over 50%, higher than that detected in other medical centers in Mexico. This rate was constant over the 11-year study, and Aspergillus exhibited the greatest frequency of sensitization among the patients.

Molecular sensitization patterns and influence of molecular diagnosis in immunotherapy prescription in children sensitized to both grass and olive pollen

BACKGROUND

The overlapping grass and olive pollen seasons in Spain and the phenomenon of cross-reactivity can make it difficult to determine the true causative agent of seasonal allergic rhinitis when only skin prick tests with whole extracts are used. The aim of the GRAMOLE study was to determine sensitization patterns to the major grass and olive pollen allergens detected using specific recombinant IgE and to explore how this knowledge affected physicians' choice of allergen-specific immunotherapy.

METHODS

Epidemiological, observational, multicenter, cross-sectional study. Results from children under 18 years of age diagnosed with seasonal allergic rhinitis by positive skin prick tests to olive and grass pollen were analyzed. Specific IgE to Phl p 1+5, Ole e 1, and Phl p 7+12 was determined. Investigators specified the optimal composition of allergen immunotherapy before and after knowing the results of the molecular diagnosis.

RESULTS

A total of 281 patients with a mean age of 13.4 years were included. Double sensitization to both major allergens was found in vitro in 76% of children for an IgE cutoff point of 0.35 kU/L. When the molecular diagnosis results were known, specialists changed the composition of the prescribed immunotherapy in 52.87% of cases.

CONCLUSIONS

Double sensitization to grass and olive pollen is common in Spain and also occurs in the pediatric population. Molecular diagnosis using specific IgE may help improve immunotherapy selection in polysensitized patients.

Allergic respiratory disease: Different allergens, different symptoms

BACKGROUND

Spanish population is rather homogeneous in its genetic and sociocultural characteristics, but allergen sensitization shows wide geographical variations. We aimed at assessing whether sensitization to different allergens in the diverse geographical areas induced different clinical and quality-of-life characteristics in adult patients with a first-time diagnosis of rhinitis and/or asthma.

METHODS

Two sequential, identically designed studies were carried out to evaluate such associations (PERFILAR I and II). PERFILAR II was an extension of PERFILAR I with additional allergens being included. Both phases were epidemiological, descriptive, cross-sectional, nonintervention multicenter studies. Participants were required to have lived for at least the last 2 years in the geographical zone. Asthma control assessment was based on ACQ-5. Health-related quality of life was evaluated with validated scales for rhinitis (ESPRINT-15) and asthma (Mini-AQLQ). Skin prick tests were used to identify sensitization to involved allergens.

RESULTS

A total of 301 physicians recruited 2711 patients for PERFILAR I+II. Sensitization to allergens was significantly different in patients with rhinitis with/without asthma. Seasonal allergens were associated with rhinitis, a longer time to asthma development, and more severe and commonly intermittent rhinitis. HDM were associated with more common rhinitis, and Alternaria was associated with asthma. The study confirms an association of geographical areas with relevant allergens and allergic clinical picture.

CONCLUSION

Different types of aeroallergens and specific sensitization profiles are associated with different allergic clinical pictures (rhinitis with/without asthma), different clinical symptoms, and different levels of severity. This could have implications to predict later clinical course and to select appropriate management approaches.

Dermatophagoides pteronyssinus: Changes in sensitisation in the past 11 years and comparison with other centres in Mexico

BACKGROUND

House dust mites are a ubiquitous air allergen in the human habitat. It has been shown that exposure to them is a fundamental factor in sensitisation and development of atopic disease. The objective of the study was to analyse changes in sensitisation to Dermatophagoides pteronyssinus (Der p.) in children treated in a tertiary level care hospital in Mexico City for a period of 11 years and compare with other studies carried out in Mexico.

METHODS

A retrospective study was performed at the Hospital Infantil de México Federico Gómez (HIMFG). Information was gathered from skin tests for Der p. performed in the Allergy Laboratory from January 2004 to April 2015. Patients 2-18 years old who presented for examination of some type of allergic condition and who had immediate hypersensitivity tests to Der p. were included in the study. Results were compared with prior reports from other institutions. Descriptive analysis and χ² statistics were used.

RESULTS

A total of 8794 patients were included in the study; 49.3% of the tests (95% CI 48-50) were positive for Der p. The percentage of monosensitised to mites was 2.7% for Der p. (95% CI 2-3). A significant difference was found between the results of older patients and those <6 years old. The frequency of sensitisation had a tendency to decrease during the 11 years analysed in all age groups.

CONCLUSIONS AND CLINICAL RELEVANCE

The frequency of sensitisation to Der p. increased with age until reaching adolescence. In the last 11 years a decrease in sensitisation to this air allergen was observed.

Mold allergens in respiratory allergy: from structure to therapy

Allergic reactions to fungi were described 300 years ago, but the importance of allergy to fungi has been underestimated for a long time. Allergens from fungi mainly cause respiratory and skin symptoms in sensitized patients. In this review, we will focus on fungi and fungal allergens involved in respiratory forms of allergy, such as allergic rhinitis and asthma. Fungi can act as indoor and outdoor respiratory allergen sources, and depending on climate conditions, the rates of sensitization in individuals attending allergy clinics range from 5% to 20%. Due to the poor quality of natural fungal allergen extracts, diagnosis of fungal allergy is hampered, and allergen-specific immunotherapy is rarely given. Several factors are responsible for the poor quality of natural fungal extracts, among which the influence of culture conditions on allergen contents. However, molecular cloning techniques have allowed us to isolate DNAs coding for fungal allergens and to produce a continuously growing panel of recombinant allergens for the diagnosis of fungal allergy. Moreover, technologies are now available for the preparation of recombinant and synthetic fungal allergen derivatives which can be used to develop safe vaccines for the treatment of fungal allergy.

Changes in allergen sensitization over the last 30 years in Korea respiratory allergic patients: a single-center

PURPOSE

Determining the culprit allergen is important for the diagnosis and management of allergic diseases. The skin prick test (SPT) has been widely used to identify culprit allergens. Skin reactivity to allergens has changed due to changes in lifestyle and outdoor environments. Therefore, the aim of the present paper was to examine changes in allergen sensitization in Korea.

METHODS

We enrolled 1,135 patients with respiratory allergic diseases who were diagnosed at Severance Hospital from January 2010 to December 2011. SPTs were performed with inhalant allergens, and were compared to our previous studies of the SPTs in the 1980s and the 1990s.

RESULTS

In the 2010s, the SPT positive rate of allergic rhinitis or allergic conjunctivitis was higher than asthma without allergic rhinitis or allergic conjunctivitis. The SPT positive rate was decreased by increments of age (P value <0.01). Skin reactivity to tree pollens was significantly increased to 36.4% in the 2010s from 19.0% in the 1990s and 8.8% in the 1980s. Among tree pollens, skin reactivity to oak (4.7%->14.4%), birch (7.1%->13.6%), alder (6.3%->13.4%) and pine (2.9%->14.3%) was significantly increased in the 2010s compared with the 1990s, respectively. Current skin reactivity to grass pollens (13.9%) and weed pollens (27.0%) has significantly decreased since the 1990s (20.3%, 40.9%, respectively). Skin reactivity to house dust mites showed no difference between the 1990s (55.2%) and the 2010s (55.6%). Skin reactivity to dog (27.3%->20.7%) and cockroach (25.3%->12.3%) have significantly decreased in the 2010s in comparison with the 1990s.

CONCLUSIONS

In light of the above results, we revealed the changes in skin reactivity to inhalant allergens that have occurred in Korean allergic patients over the past three decades. Since outdoor environmental factors such as the amount of pollen, global warming and plant distribution causes the changes in skin reactivity, further study and continuous close observation will be needed.

Importance of allergic rhinitis management in achieving asthma control: ARIA update

Asthma continues to be a major burden for the health and healthcare of people worldwide. The recent updates of the Global Initiative for Asthma and the National Heart, Lung and Blood Institute asthma guidelines stress the need for achieving and monitoring asthma 'control', emphasizing the importance of identifying, assessing and treating comorbid conditions. Allergic rhinitis (AR) is a major comorbid condition in people with asthma and is related to inflammation of the upper portions of the airway. Recognizing and treating AR has been shown to improve asthma control, specifically by decreasing rates of asthma attacks or asthma exacerbations. In 2008, updated Allergic Rhinitis in Asthma (ARIA) guidelines were published. The updated version of the guidelines has a familiar look, with classification systems and care algorithms that are similar to those presented in other asthma guidelines. The new ARIA guidelines make one major change that should affect the care of adults and children with asthma: everyone with asthma should be assessed for AR. In addition, AR should be considered a risk factor for asthma, and all children and adults with AR, especially persistent AR, should be assessed for asthma, including testing lung function for reversible obstruction whenever feasible. Treatment for AR follows a similar format to that for asthma, including symptom management, treatment of chronic inflammation, identification and management of triggers, including allergens, and ongoing education for self-management. Pharmacotherapies that address both asthma and AR include corticosteroids (intranasal and inhaled), leukotriene receptor antagonists, immunomodulation or immunotherapy. Too often, pharmacotherapy is not supplemented by the necessary education and evaluation related to allergen, trigger identification and management.

Calculating the prevalence of atopy in children

BACKGROUND

Atopy is an important risk factor for asthma, rhinitis, atopic eczema and urticaria. For this reason, several studies have been done to determine the prevalence of atopy in the paediatric population. The important differences among these studies do not allow the extrapolating of results. In this study, we calculate the prevalence of atopy and atopy-related diseases in a paediatric population using a different methodology.

METHODS

Retrospective study among children referred for drug allergy in which the latter was discarded. We evaluated the prevalence of atopy (measured by allergen sensitisation), asthma, rhinitis, urticaria, atopic eczema and their characteristics.

RESULTS

Three hundred and forty-two patients were studied for adverse drug reaction. This was discarded in 325/342 patients. 20 % of the children in the sample were atopic. Atopy prevalence increased with age. Some atopy related disease was observed in 83/325 (25.5 %) children. Among these children allergen sensitisation increased from 42.3 % in the 0-3 years age group to 93.3 % in the 7-14 age group (p < 0.0001). Prevalence of asthma was 11.5 %, 10.2 % and 7 % in the 0-3, 4-6 and 7-14 age groups, respectively. Prevalence of rhinoconjunctivitis increased through age groups with a prevalence of 20 % among the 7 to 14-year old children.

CONCLUSION

The use of this type of methodology seems to be correct to estimate the prevalence of atopy. Prevalence of allergen sensitisation is very high among 7 to 14-year old children with asthma and/or rhinoconjunctivitis.