Sensitization and exposure to pet allergens in asthmatics versus non-asthmatics with allergic rhinitis

Pet Ownership Increases the Exhaled Nitric Oxide and Asthma Severity in Children With Atopic Asthma

Exposure to pets can trigger symptoms in asthmatic children sensitized to pets. However, little is known about the association between pet ownership and asthma morbidity in children who are not sensitized to pets. We aimed to investigate the effect of pets on lung function, airway inflammation, and morbidity in children with asthma, and to determine whether the effect of exposure to pets vary based on pet sensitization status. A total of 975 asthmatic children, aged 5-15 years, were enrolled in the Korean Childhood Asthma Study. Pet ownership and asthma morbidity were evaluated by questionnaires or pediatrician evaluations. Pulmonary function, fractional exhaled nitric oxide (FeNO), and atopic status were assessed. FeNO levels were significantly higher in children with pets than in those without pets. Pet ownership significantly increased FeNO levels in atopic asthmatic children, irrespective of pet sensitization status. In children sensitized to pets, the geometric mean was 46.6 (range of 1 standard deviation, 26.9-81.5) for those with pets vs. 27.2 (13.8-53.6) for those without pets (P < 0.001). In children without sensitization to pets, the geometric mean was 37.3 (15.0-53.6) for pet owners vs. 25.2 (12.9-49.2) for non-owners (P = 0.014). The multiple regression analysis also revealed that pet ownership was significantly associated with increased FeNO levels and asthma severity in atopic asthmatic children. Pet ownership increased the FeNO levels and asthma severity, regardless of pet sensitization status, in children with atopic asthma. Exposure to pets could increase airway inflammation and disease severity even in atopic asthmatic children who are not sensitized to pets.

Characteristics of children with cat sensitivity: a prospective cross-sectional study

BACKGROUND

Animal dander is one of the most common respiratory allergens in children, and there is evidence that cat sensitivity is a risk factor for asthma and allergic rhinitis. In this study, it was aimed to evaluate children with cat sensitivity and to identify their demographic and clinical characteristics.

METHODS

Patients who were found to be sensitive to cats following skin prick tests performed in our allergy clinic over a period of one year (and two control groups), were included in the study. Patients in the study and control groups filled in a questionnaire including demographic and clinical characteristics.

RESULTS

The prevalence of cat sensitivity in our allergy clinic was 6% (182/3033). The most common diagnoses in patients were 41.8% allergic rhinitis, 25.8% asthma, and 13.2% allergic rhinitis + asthma. Allergic rhinitis symptoms were the most prevalent symptom associated with cat contact (29.4%), whereas 28% of the patients were asymptomatic. Only 17.3% had a cat at home and 13.4% had cat exposure apart from home but having a cat at home was significantly higher than the control groups (p < 0.05). Eosinophilia was present in 54.6% of the patients, and 17.3% had blood tIgE levels of >1000 IU/mL. Eosinophilia and tIgE levels were significantly higher than both control groups (p < 0.05).

DISCUSSION

Cat ownership can affect the development of cat sensitivity but the majority of patients with cat sensitivity are not cat owners. Elevated tIgE levels (> 1000 IU/mL) may be associated with cat sensitivity, these patients should be evaluated for cat sensitivity, even if they do not report symptoms with cat contact.

Exposures in the Indoor Environment and Prevalence of Allergic Conditions in the United States of America

Our study examines the association of the presence of mildew, cockroaches, and pets in homes as well as household dust allergens with the prevalence and/or severity of allergic diseases. No study has concurrently assessed home environment exposures in relation to allergic conditions in the general US population. Data from 5409 participants from the 2005–2006 National Health and Nutrition Examination Survey (NHANES) living in their current homes for ≥one year were analyzed. Multivariate logistic regression analyses between home exposures and allergic diseases prevalence and severity were performed. In adjusted analyses, mildew was associated with higher current asthma, allergies, and allergic rhinitis prevalence; endotoxin, with higher current asthma prevalence; and dust Canis familiaris (Can f) 1, with higher allergic rhinitis prevalence. However, presence of cockroaches and dust Dermatophagoides farinae (Der f) 1 were associated, respectively, with lower current asthma and allergies prevalence. Presence of mildew, dust Der f1, Dermatophagoides pteronyssinus (Der p) 1, Felis domesticus (Fel d) 1, and endotoxin were all associated with asthma and/or wheeze severity. Non-atopic asthma was more frequent with mildew and/or musty smell dust and higher dust Fel d1 concentration, while atopic asthma was more prevalent with higher Can f1 and endotoxin concentrations in dust. This study confirms previous relationships and reports novel associations, generating hypotheses for future research.

Association of pet-keeping in home with self-reported asthma and asthma-related symptoms in 11611 school children from China

OBJECTIVE

We conducted a cross-sectional study to investigate the associations between domestic pets and respiratory health in children.

METHODS

We randomly recruited 11,611 school children from Zhongshan, a southern city in China. Information about the respiratory symptoms and disease history of the recruited children, the status of domestic pets, and other related risk factors were collected from March to July 2016.

RESULTS

We identified cat-keeping at home increases the risk of persistent cough (OR, 1.77; 95%CI, 1.03-3.05); poultry-keeping at home increases the risk of current asthma (OR, 3.87; 95%CI, 1.08-13.92) and allergic rhinitis (OR, 1.84; 95%CI, 1.01-3.37); sleeping with pets increases the risk of persistent phlegm (OR, 5.04; 95%CI, 1.05-24.28), doctor-diagnosed asthma (OR, 3.35; 95%CI, 1.31-8.57) and current asthma (OR, 4.94; 95%CI, 1.05-23.31) in children.

CONCLUSIONS

Cat-keeping and molds on the wall of the house had the multiplicative and additive interaction in doctor-diagnosed asthma. In conclusion, pet-keeping increased the risk of respiratory symptoms in children.

The Pattern of Sensitization Influences Exhaled and Nasal Nitric Oxide Levels in Young Adults

Nitric oxide (NO) from upper (nasal NO, nNO) or lower airways (fractional exhaled NO, FeNO) is considered a surrogate marker for Th2-type inflammation, which is influenced by atopy. The aim of this study was to analyze nNO and FeNO in regard to qualitative and quantitative aspects of sensitization. We evaluated 244 non-smoking young adults. All of them were first-year students recruited for a longitudinal study. An inhalation allergy screening tool was used for atopy definition (specific immunoglobulin E (sIgE) to sx1 ≥ 0.35 kU/L), and also sIgE response to three inhalant perennial allergens, house dust mite (HDM, d1), cat (e1), and dog (e5), was determined in the non-pollen season. With respect to sx1, 100 subjects could be classified as atopic. Sensitization to one, two, or three perennial allergens could be demonstrated in 46, 10, and 16 students, respectively. The subjects with positive IgE response to sx1, but not sensitized to HDM, cat, and/or dog, had FeNO levels comparable to those of non-atopic subjects (13.5 vs. 13.0 ppb, respectively; p = 0.485). These levels were significantly lower compared to atopic subjects being sensitized to any perennial allergen (19.0 ppb; p = 0.0003). After grouping the atopic subjects for perennial sensitization patterns, significantly higher FeNO could be detected in subjects with poly-sensitization (n = 26; 26.0 ppb) compared to the mono-sensitized ones (n = 46; 18.0 ppb; p = 0.023). Regarding nNO, no differences could be observed. Applying a two-way ANOVA, we could reveal a significant correlation of specific HDM-IgE CAP-class with FeNO (p < 0.0001) and nNO levels (p = 0.007). Finally, a significant relationship was found between nNO and FeNO for the whole cohort (p < 0.0001). In summary, our findings support the argument that atopy and perennial sensitization should be considered for the interpretation of NO.

Allergic rhinitis and asthma assessment of risk factors in pediatric patients: A systematic review

Allergic rhinitis (AR) is the most prevalent allergic disease in children and can be associated with asthma (A); this association can have significant effect on child's quality of life. The objective of this work was to systematically review existing literature on the risk factors of AR and A in children to better understand the link between these two diseases. We performed a literature search over the last 25 years in PubMed and Medline. Inclusion criteria comprised English language papers containing original human data with greater than 30 subjects and papers that statistically analyze the relationship between AR and A and the risk factor(s), in children population. A statistically significant correlation was found between children with AR and A and ambient Polycyclic Aromatic Hydrocarbons exposure, live in an industrialized city with elevated traffic, dampness and moulds exposure, electric cooking, male gender, single nucleotide polymorphisms in PTNP22 gene and CTLA-4 gene, fast food and margarine products consumption, use of paracetamol in last year, history of tuberculosis, parental atopy, high total serum IgE, antibiotics in uterus and infections in uterus exposure, history of formula feeding and caesarian section. A strong and complex link between AR and A was accounted: A represents a major risk factor for the onset of AR, that correlates with more severe asthmatic symptoms. Even the onset of A in a child with AR worsen it. The interaction of genetic and environmental risk factors and the consequent epigenetic, microbiota and immunological changes, were found to led to the development of AR and A in children, with both atopic and non-atopic pathways. Close monitoring of evidenced risk factors may help with an early recognize and treat A in patients with AR.

International Consensus Statement on Allergy and Rhinology: Allergic Rhinitis

BACKGROUND

Critical examination of the quality and validity of available allergic rhinitis (AR) literature is necessary to improve understanding and to appropriately translate this knowledge to clinical care of the AR patient. To evaluate the existing AR literature, international multidisciplinary experts with an interest in AR have produced the International Consensus statement on Allergy and Rhinology: Allergic Rhinitis (ICAR:AR).

METHODS

Using previously described methodology, specific topics were developed relating to AR. Each topic was assigned a literature review, evidence-based review (EBR), or evidence-based review with recommendations (EBRR) format as dictated by available evidence and purpose within the ICAR:AR document. Following iterative reviews of each topic, the ICAR:AR document was synthesized and reviewed by all authors for consensus.

RESULTS

The ICAR:AR document addresses over 100 individual topics related to AR, including diagnosis, pathophysiology, epidemiology, disease burden, risk factors for the development of AR, allergy testing modalities, treatment, and other conditions/comorbidities associated with AR.

CONCLUSION

This critical review of the AR literature has identified several strengths; providers can be confident that treatment decisions are supported by rigorous studies. However, there are also substantial gaps in the AR literature. These knowledge gaps should be viewed as opportunities for improvement, as often the things that we teach and the medicine that we practice are not based on the best quality evidence. This document aims to highlight the strengths and weaknesses of the AR literature to identify areas for future AR research and improved understanding.

Dog and Cat Allergies and Allergen Avoidance Measures in Korean Adult Pet Owners Who Participated in a Pet Exhibition

Purpose

This study evaluated dog and cat allergies and their association with allergen avoidance measures in Korean adults.

Methods

The study population consisted of 537 adults who currently kept dogs or cats and participated in a pet exhibition in Korea. The subjects were asked to complete questionnaires regarding pet ownership, allergen avoidance, and allergy symptoms, and underwent skin prick tests. They were considered to have a dog or cat allergy if they suffered from one or more of allergy symptoms during contact with their pets.

Results

In total, 103 of 407 dog owners (25.3%) and 45 of 130 cat owners (34.6%) had a dog or cat allergy, respectively. Dog owners kept 1.3±1.5 dogs; this number did not differ according to the presence of dog allergy. Dog owners with a dog allergy had owned their dogs longer than those without (88.0±72.0 vs 67.5±72.7 months, P<0.05). Cat owners kept 2.1±3.6 cats; this number did not differ according to the presence of cat allergy, nor did the duration of cat ownership. Cat owners with a cat allergy had facial contact and slept with their cats less frequently (8.6±11.9 vs 18.3±27.0 times/day, P<0.01; 71.1% vs 81.2%, P<0.05); however, they had their cats shaved and beds cleaned less frequently than those without (1.8±3.3 vs 3.2±4.4 times/year, P<0.05; 1.5±1.5 vs 3.9±6.0 times/month, P<0.01).

Conclusions

Cat owners with a cat allergy tried to minimize contact with their cats, but efforts to avoid indoor cat allergens were lower than those without. In comparison, dog owners with a dog allergy had kept their dogs for longer time than those without; however, current contact with their dogs and allergen avoidance measures did not differ between the 2 groups.

Cohort profile of the Young-HUNT Study, Norway: a population-based study of adolescents

The Young-HUNT Study is the adolescent part (13-19 years) of HUNT, the Nord-Trøndelag Health Study, Norway. Three cross-sectional surveys have been conducted: Young-HUNT1 (1995-97), Young-HUNT2 (2000-01) and Young-HUNT3 (2006-08). Major public health issues, including somatic and mental health, quality of life and health behaviours are covered. Young-HUNT was performed in schools visited by trained nurses. Data collection included self-reported questionnaires, structured interviews, clinical measurements and, in Young-HUNT3, buccal smears. The total response rates varied from 90% to 83% and the Young-HUNT database includes 17 820 teenagers. Some Young-HUNT1 participants constitute the baseline for two follow-up studies: a 4-year follow-up through adolescence to Young-HUNT2 and an 11-year follow-up into young adulthood to the adult HUNT3. Longitudinal data are also obtained by linkage of data from Young-HUNT to different national health registers. Linkage to family registers allows the possibility of studying genetic and environmental interactions through generations. Presently 20 PhD students are working with the data, 11 Young-HUNT based PhD theses have been completed and more than 50 scientific papers published.

Direct and indirect exposure to horse: risk for sensitization and asthma

Most studies on the sensitization to horse allergens in populations without professional exposure have been carried out in geographical areas where the rate of horse ownership is high and horse riding is popular. Very few studies have been carried out in populations living in large urban areas. This gap in the literature probably reflects the widespread view that prevalence of horse-related allergy is low in urban populations because the latter are not regularly exposed to horses. On the contrary, we suggest that urban areas constitute a model useful to study potential modalities of exposure and sensitization to horse allergen by other routes of exposure than horse-riding. In this article, we describe the risks related to various modalities of exposure to horse allergen, clinical aspects of airway sensitization to horse allergens in patients living in urban areas, and non-occupational exposure to horse allergen. In addition, we illuminate some aspects related to dispersion of horse allergens from sources such as stables to indoor environments.

Exhaled nitric oxide (FeNO) as a non-invasive marker of airway inflammation

Nitric oxide (NO), previously very famous for being an environmental pollutant in the field of pulmonary medicine, is now known as the smallest, lightest, and most famed molecule to act as a biological messenger. Furthermore, recent basic researches have revealed the production mechanisms and physiological functions of nitric oxide in the lung, and clinical researches have been clarifying its tight relation to airway inflammation in asthma. On the bases of this knowledge, fractional nitric oxide (FeNO) has now been introduced as one of the most practical tools for the diagnosis and management of bronchial asthma.

The association between fractional exhaled nitric oxide (FeNO) and cat dander in asthmatic children

BACKGROUND

The aim of our study was to assess risk factors of increased FeNO in asthmatic children with no cat at home.

METHODS

It was a retrospective, cross-sectional study. We evaluated data from medical documentation of children with asthma: FeNO results, allergen sensitization, seasonal allergen exposure, FEV(1), allergic rhinitis (AR) diagnosis and cat presence at home. We assessed asthma severity using mean doses of inhaled glucocorticosteroids and a management approach based on control according to the newest guidelines of Global Initiative for Asthma (GINA) throughout the last three months before the measurement of FeNO and spirometry.

RESULTS

316 patients (age 6-18) completed the study. Sensitization to cat dander was associated with the highest median value of FeNO concentration compared to other allergens in our patients (28,4ppb) and co-existing sensitization did not affect FeNO level. Median levels of FeNO increased linearly with patient's age. In asthmatics with AR, the levels of FeNO were increased significantly compared to asthmatics without AR (20.8 vs. 16.3, respectively). We showed that in patients without AR, sensitization to cat allergen was associated with more severe asthma in comparison to other perennial allergy (step 4 vs. other steps according to GINA treatment steps). The above relation was not observed in patients with AR. We did not observe correlation between allergy profile and FEV(1) among patients in neither subgroup nor in general population.

CONCLUSIONS

We revealed that sensitization to cat dander was associated with the highest increase of FeNO concentration compared to other allergens in patients not having any cat at home ever. We also observed that in patients without allergic rhinitis, sensitization to cat allergen, compared to other perennial allergy, was associated with more severe asthma.

Decreased fraction of exhaled nitric oxide in obese subjects with asthma symptoms: data from the population study INTERGENE/ADONIX

BACKGROUND

Several studies have demonstrated an association between obesity and asthma. However, it is uncertain if fraction of exhaled nitric oxide (Feno), which is used as a marker of airway inflammation, and atopy are associated with BMI. The aim of this study was to examine if obese subjects with asthma symptoms have a different phenotype of asthma than nonobese subjects as indicated by Feno.

METHODS

The subjects (N = 2,187) consisted of women and men, aged 25 to 74, living in Gothenburg, Sweden, who participated in the randomly selected INTERGENE study cohort. Measurements included anthropometric measures, bioelectric impedance, Feno, pulmonary function, and blood samples for IgE; questionnaires included items on respiratory symptoms. Obesity was defined as BMI ≥ 30 kg/m(2). In this cross-sectional analysis, general linear models were used to analyze how Feno was associated with anthropometry, body composition, wheezing, and atopy.

RESULTS

In nonobese subjects, wheezing was associated with raised Feno and atopy, whereas in contrast, obese subjects who reported wheezing had lower Feno than obese subjects without wheezing (16.1 vs 19.1 parts per billion, P < .01). The prevalence of atopy was similar in both of those subgroups (25.0% vs 20.7%, P = .4). Similarly, in 395 subjects (19%) who reported wheezing, Feno was negatively associated with BMI, waist-to-hip ratio, and percentage of body fat, whereas no significant relationships were observed in those without respiratory symptoms.

CONCLUSIONS

Wheezing was significantly associated with reduced Feno in obese subjects, whereas there was a positive association between wheezing and Feno among the nonobese subjects, indicating a possible difference in asthma phenotype, based on body weight.

Exhaled NO among inner-city children in New York City

BACKGROUND

Fractional exhaled nitric oxide (FeNO) has been proposed as a biomarker of airway inflammation for cohort studies of asthma.

OBJECTIVES

To assess the association between FeNO and asthma symptoms among 7-year-old children living in an inner-city community. To test the association between environmental tobacco smoke (ETS) exposure (previous and current) and FeNO among these children.

METHODS

As part of a longitudinal study of asthma, children recruited in Head Start centers at age 4 had offline FeNO and lung function testing at age 7. Children with allergen-specific immunoglobulin E (IgE) (≥0.35 IU/mL) at age 7 were considered seroatopic. ETS exposure at ages 4 and 7 was assessed by questionnaire.

RESULTS

Of 144 participating children, 89 had complete questionnaire data and achieved valid FeNO and lung function tests. Children with reported wheeze in the previous 12 months (n = 19) had higher FeNO than those without wheeze (n = 70) (geometric means 17.0 vs. 11.0 ppb, p = .005). FeNO remained significantly associated with wheeze (p = .031), after adjusting for seroatopy and forced expiratory volume in 1 second (FEV₁) in multivariable regression. FeNO at age 7 was positively associated with domestic ETS exposure at age 4 (29%) (β = 0.36, p = .015) but inversely associated with ETS exposure at age 7 (16%) (β = -0.74, p < .001).

CONCLUSIONS

Given its association with current wheeze, independent of seroatopy and lung function, FeNO provides a relevant outcome measure for studies in inner-city communities. While compelling, the positive association between ETS exposure at age 4 and a marker of airway inflammation at age 7 should be confirmed in a larger study.

The role of cats and dogs in asthma and allergy--a systematic review

Studies have reported contradictory effects of cat and dog exposure on allergy, resulting in inconsistent recommendations on animal avoidance. We conducted a systematic review of observational studies published in English from 2000 to January 2009. It shows in this review that the reported exposure-response relationships are contradictory. A total of 17 and 13 birth cohort studies on cat and dog exposure, respectively, are included in the review. Most of the birth cohort studies found that cat or dog exposure in early life had no effect on the development of asthma or wheezing symptoms and dog exposure during infancy was found to protect children from developing sensitization against aeroallergens. A total of 7 and 6 prospective studies in school-age children or adults on cat and dog exposure, respectively, are included in this review and most of these studies suggested an inverse association between cat exposure and asthma and wheezing symptoms. As for cross-sectional studies, 26 and 21 studies on cat and dog exposure, respectively, are included in this review, which cover a broad range of age groups and geographical areas, and reported inconsistent results. The evidence summarised in this systematic review needs to be interpreted with caution, the inconsistent study results may be due to study design, exposure assessment, and avoidance measure. The exposure-response relationships may also alter in geographical areas where the community prevalence of cats and dogs are significantly different. However, as the evidence of the effects of pet keeping on subsequent development of asthma or allergic diseases presented in this review are not overwhelmingly strong, the decision of whether to keep a cat or a dog in the family should be based on arguments other than the concern of developing asthma and allergy.

Horse allergens: An underestimated risk for allergic sensitization in an urban atopic population without occupational exposure

BACKGROUND

Data on allergic sensitization to horse allergen in modern urban areas are scarce. The aim of this study was to investigate the characteristics of allergic sensitization and the modality of exposure to horse allergens in atopic patients living in an urban area and without occupational exposure to horse and/or horse-derived materials.

METHODS

From among 1822 consecutive outpatients, we selected all subjects who had an immediate skin reaction to horse dander. We recorded the patients' clinical history including a meticulous evaluation of the possibility and eventual modality of horse exposure, and the results of skin-prick tests (SPT) and total/specific IgE antibody analyses.

RESULTS

Of 1201 SPT-positive patients, 35 (3.43%) were sensitized to horse dander. No patient was mono-sensitized. Six individuals reported having direct horse contact, 10 subjects had occasional contact with horse owners (indirect exposure), and 19 denied direct or indirect exposure to horses or horse allergens. Twenty of the 35 horse-sensitized patients reported both nasal and bronchial symptoms, 14 had rhinitis without asthma and one had asthma without rhinitis.

CONCLUSIONS

Our results suggest that allergic sensitization to horse allergens is more frequent than expected in urban-dwelling subjects without direct or occupational exposure to horses. Highly atopic individuals or individuals who are sensitized to common pet dander should undergo SPT and evaluation of serum specific IgE before starting activities involving regular contact with horses such as riding, and before entering environments associated with horses.

Effect of nasal steroid treatment on airway inflammation determined by exhaled nitric oxide in allergic schoolchildren with perennial rhinitis and asthma

Rhinitis is common in asthmatic schoolchildren who are allergic to animal dander and constantly and indirectly exposed to these allergens in their everyday environment. As a patho-physiological linkage between nasal and bronchial inflammation has been proposed to exist, the primary objective of this study was to determine whether nasal administration of mometasone furoate (MSNF) can reduce bronchial inflammation, as reflected in the level of exhaled nitric oxide (F(E)NO) in asthmatic schoolchildren with dander allergy and mild-to-moderate rhinitis. Forty such children were assigned randomly to be treated for 4 wk with MSNF or placebo, employing a double-blind procedure. F(E)NO was the primary end-point measured and secondary end-points were nasal levels of NO, the concentration of eosinophilic cationic protein (ECP) in nasal lavage, the relative numbers of eosinophils in blood, forced expiratory volume in 1 s (FEV(1)), peak expiratory flow (PEF) and scoring of symptoms. There was no significant difference in the F(E)NO values of the treated and control groups at any time-point, whereas the nasal level of ECP was lower in the treated group compared with placebo (p = 0.05) on both days 7 and 28, and compared with baseline for the treated group (p = 0.06 on day 7, p = 0.02 on day 28). Furthermore, the mean blood eosinophil count decreased in the treated group, which also demonstrated lower scores for nasal symptoms compared with placebo, but neither of these differences were statistically significant. FEV(1), PEF and nasal levels of NO remained unchanged in both groups. Four weeks of nasal treatment with MSNF had no effect on bronchial inflammation, as reflected by exhaled NO, whereas signs of nasal and systemic eosinophil activation were reduced. Thus, nasal administration of a steroid as a strategy to reduce asthmatic inflammation remains questionable in mild-to-moderately severe cases of perennial rhinitis and asthma.

Off-line fractional exhaled nitric oxide measurement is useful to screen allergic airway inflammation in an adult population

To determine whether off-line fractional exhaled nitric oxide (FeNO) measurement is applicable to screen allergic airway inflammation for epidemiologic studies, we examined 280 adults, measuring off-line FeNO samplings, pulmonary function, and serum immunoglobulin E (IgE). Subjects with recurrent wheeze (recurrent wheezers) had significantly higher FeNO and IgE levels and significantly lower forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC) than non-wheezers. Statistical analysis showed that FeNO and FEV1/FVC were significant predictors for recurrent wheezers, independent of smoking. The cut-off FeNO level for screening allergic airway inflammation was 38 ppb in non-smokers and 32.9 ppb in smokers. Thus, off-line FeNO can be used as a good marker to screen allergic airway inflammation, regardless of smoking.

Indoor environmental influences on children's asthma

The burden of asthma for children in the United States is substantial and has continued to rise for the past 2 decades. There is growing evidence that the indoor environment may play an important role in the pathogenesis of childhood asthma. This article first reviews the effects of indoor allergen exposure and sensitization on asthma incidence and morbidity, focusing on dust mite, cockroach, pet, and rodent allergens. It then addresses the effects of indoor air pollutants (ozone, particulate matter, nitrogen dioxide, environmental tobacco smoke, sulfur dioxide, and carbon monoxide) on asthma morbidity.

Allergic rhinitis with or without concomitant asthma: difference in perception of dyspnoea and levels of fractional exhaled nitric oxide

BACKGROUND/AIM

Allergic rhinitis (AR) is a risk factor for developing clinical asthma. Moreover, AR is often associated with bronchial hyper-responsiveness (BHR). The aim of the present study was to investigate whether patients with AR and asthma differed from AR with or without BHR in degree of perception of dyspnoea and airway inflammation, measured as fractionated exhaled nitric oxide (NO).

MATERIALS

Twenty-nine patients with seasonal AR (timothy) were investigated with metacholine challenge test. Fourteen healthy non-reactive subjects served as controls.

METHODS

(1) Metacholine challenge test, cut-off value forced expiratory volume in 1 s (FEV(1)) PD20 2,000 microg. Slope value for metacholine was calculated as %fall in FEV(1)/mol metacholine. Dyspnoea during challenge was measured with a 10-graded modified Borg score. (2) Measurement of fractional-exhaled nitric oxide (FENO) at flow rate 50 mL/s.

RESULTS

Eighteen patients reported AR only, without asthma symptoms, and 12 (67%) were BHR. Eleven subjects had both rhinitis and asthma symptoms. Patients with rhinitis and asthma reported significantly more dyspnoea per percent fall in FEV(1) compared with those with rhinitis and BHR. Moreover, those with rhinitis and asthma had significantly higher NO values compared with those with rhinitis and BHR.

CONCLUSION

The difference between rhinitis patients with or without asthma symptoms seems to be mainly a question of perception of dyspnoea. However, FENO measurement indicates that dyspnoea may also be associated with increased inflammatory activity in the peripheral airways.

Pets and the development of allergic sensitization

Sensitization to pets remains a risk factor for asthma and rhinitis, and can occur in people who have never lived with a pet. Several reports have indicated that living with a pet reduces the risk for becoming sensitized to that pet. Having a pet in the home gives exposure to more than just allergens. In areas with high frequency of pet ownership, community exposure to pet allergens is almost certainly sufficient to induce sensitization among non-pet owners. In this review, we examine the results of recent studies that have investigated the relationship between pet ownership, specific sensitization to that pet, and allergic sensitization in general. For cat ownership, the results are inconsistent between studies of similar design, with some studies suggesting an increase in risk and others a decrease among cat owners. For dogs, results are more consistent, generally suggesting that owning a dog has no effect or indeed may be protective against the development of specific sensitization to dog and allergic sensitization in general.

Cutaneous and serological responses to cat allergen in adults exposed or not to cats

BACKGROUND

The relationship between pet ownership and the risk of developing respiratory allergic sensitization to pet allergens is still controversial.

OBJECTIVE

To determine the degree of cutaneous immediate hypersensitivity and the levels of specific IgE and IgG4 antibodies to cat allergen in cat sensitized patients directly or indirectly exposed to this animal.

METHODS

We studied 112 adolescents and adults sensitized to cat allergens (43 with and 69 without a cat at home). There were also 52 control subjects, 27 atopic non-sensitized to cat and 25 non-atopic. The degree of immediate hypersensitivity was assessed by using, in duplicate, skin prick test with four five-fold dilutions of cat hair allergen extract with the content of its major allergen Fel d 1 quantified in micrograms plus positive (10 mg/ml histamine chlorhydrate) and negative (saline solution) controls. The resulting wheal areas were analysed by means of Parallel Line Assay. A blood sample was collected from every patient and control subjects for the evaluation of serological cat specific IgE and IgG4 antibodies.

RESULTS

Patients with cat at home had a lower cutaneous response than patients without this pet. The difference in the skin sensitivity was estimated in 3.4 times (P<0.01). There was no statistical difference between the levels of cat specific IgE antibodies in the two groups of patients (P=0.065). The levels of Fel d 1 specific IgG4 antibodies showed a statistically significant association with the presence of cat at home, with higher levels in patients owing cat at home than in patients without this pet (P<0.001).

CONCLUSION

The results of this study demonstrate that direct cat exposure in adolescents and adults with respiratory allergy is associated with a lower cutaneous response to cat allergenic extract, assessed by SPT and compared with indirect exposure. In patients with cat at home mean levels of specific IgE are statistically comparable whereas the levels of IgG4 are higher in comparison with subjects not exposed to cats. The role of indirect exposure to cat allergens in airways sensitization also in adults is emphasized. Moreover, patients with cat at home show a cutaneous and serological sensitization to cat allergen not higher in comparison with subjects not exposed to cats.

Exhaled nitric oxide: relation to sensitization and respiratory symptoms

BACKGROUND

Conflicting data have been presented as to whether nitric oxide (NO) in exhaled air is merely reflecting atopy rather than airway inflammation.

OBJECTIVE

To investigate the relationship between exhaled NO (eNO) and nasal NO (nNO), respiratory symptoms, and atopy, in the context of a cross-sectional study of the respiratory health of bleachery workers.

METHODS

Two hundred and forty-six non-smoking bleachery and paper-mill workers answered a questionnaire and were examined by measurements of eNO and nNO and spirometry, outside the pollen season. Blood samples were collected and analysed for specific IgE against common aeroallergens (birch, timothy, cat and house dust mite). Atopy was defined as a positive Phadiatop trade mark test.

RESULTS

The atopic and the non-atopic subjects without asthma or rhinitis had similar levels of eNO. Subjects reporting asthma or rhinitis who were also sensitized to perennial allergens had higher levels of eNO, whereas those sensitized to only seasonal allergens had similar eNO levels as non-atopic subjects with asthma or rhinitis. In multiple linear regression models adjusted for nNO, eNO was associated with asthma and sensitization to perennial allergens.

CONCLUSION

The results indicate that only atopic subjects who have recently been exposed to the relevant allergen have elevated levels of eNO. Atopic subjects who are not being exposed to a relevant allergen or have never experienced symptoms of asthma or rhinitis show normal eNO. These data indicate that eNO relates to airway inflammation in atopic subjects.

Addressing the prevalence of respiratory allergy in the home environment

Respiratory allergy prevalence has always depended both on genetic predisposition and specific environmental allergenic stimulation that leads to sensitization and eventual symptomatic disease. Changes brought about by modern technology that have afforded a higher quality of life have also accidentally increased the levels of many respirable and ingestible allergens in the environment. In many cases these higher levels of exposure have exceeded individual thresholds, resulting in the phenotypic expression of allergy in many individuals who were previously asymptomatic even though they were genotypically predisposed to developing allergies. Prevalence can be decreased only if susceptible populations are identified as early as possible through careful family history taking and appropriate testing for sensitivity and if exposure to selected allergens is controlled.

Pet-keeping in childhood and adult asthma and hay fever: European community respiratory health survey

BACKGROUND

Whether pet-keeping early in life protects against or promotes allergy remains unclear.

OBJECTIVE

Our aim was to examine the effects of childhood pet-keeping on adult allergic disease in a large international population-based study, including information on sensitization, adult pet-keeping, and pet prevalence in the populations.

METHODS

We used information from structured interviews (n = 18,530) and specific IgE to common aeroallergens in blood samples (n = 13,932) from participants in the European Community Respiratory Health Survey (ECRHS) to analyze the associations between keeping pets and adult asthma and hay fever.

RESULTS

Keeping cats in childhood was associated with asthma only among atopic subjects, an association that varied between centers (P =.002) and was stronger where cats where less common (< 40% cats: odds ratio(wheeze) [OR(wheeze)] = 1.84, 95% CI = 1.31-2.57; 40%-60% cats: OR(wheeze) = 1.33, 95% CI = 1.10-1.61; > or =60% cats: OR(wheeze) = 0.98, 95% CI = 0.73-1.33). Dogs owned in childhood or adulthood were associated with asthma among nonatopic subjects (childhood: OR(wheeze) = 1.28, 95% CI = 1.13-1.46; adulthood: OR(wheeze) = 1.31, 95% CI = 1.14-1.51; both: OR(wheeze) = 1.69, 95% CI = 1.40-2.04). In atopic subjects, those who had owned dogs in childhood had less hay fever (OR = 0.85; 95% CI = 0.73-0.98) and no increased risk of asthma (OR(wheeze) = 1.01, 95% CI = 0.87-1.17). Respiratory symptoms were more common in subjects who had owned birds during childhood (OR(wheeze) = 1.12; 95% CI = 1.02-1.23) independent of sensitization.

CONCLUSIONS

The effects of pet-keeping in childhood varied according to the type of pet, the allergic sensitization of the individual, and the wider environmental exposure to allergen. Cats owned in childhood were associated with more asthma in sensitized adults who grew up in areas with a low community prevalence of cats. Dogs owned in childhood seemed to protect against adult allergic disease but promote nonallergic asthma.

Gender differences in asthma prevalence may depend on how asthma is defined

BACKGROUND

Asthma may be defined either as wheeze within the previous 12 months (current wheeze) doctor-diagnosed asthma (DDA), or current wheeze plus confirmed airway hyperresponsiveness (AHR).

AIMS

We wanted to estimate asthma prevalence in randomly selected adolescents based on different criteria for asthma diagnosis, study gender differences in reported asthma-like symptoms vs DDA, and relate our findings to measurements of AHR, levels of exhaled nitric oxide (ENO) and total IgE.

METHODS

As part of the health survey of North-Trøndelag (HUNT), 8571 adolescents aged 13-19 years were investigated with an interview on allergic and respiratory symptoms (phase I study). Of these, 401 subjects who reported wheeze within the previous 12 months (current wheeze) and 213 non-symptomatic controls were randomly selected and investigated with allergy screening, methacholine bronchoprovocation test and measurements of ENO (phase II study).

RESULTS

In the phase I study prevalence of current wheeze was 26% (30% in girls and 23% in boys, P < 0.01). Prevalence of DDA was 10.8% (10.5% in girls and 11% in boys). Among subjects with current wheeze, the likelihood of having DDA was reduced in girls compared to boys, odds ratio (95% CI) 0.82 (0.68-0.98) which was partly explained by a longer history of wheeze among boys. In the phase II study, although more girls than boys with current wheeze had AHR (62% versus 50%, P < 0.02) more boys than girls reported DDA (44% vs. 32%, P < 0.02). Of the objective parameters, increased levels of ENO most strongly increased the risk of having DDA.

CONCLUSIONS

When asthma is defined as DDA, there is a risk of underestimating the prevalence of asthma, especially among girls.

Effect of nasal triamcinolone acetonide on lower airway inflammatory markers in patients with allergic rhinitis

BACKGROUND

Allergic rhinitis (AR) and asthma are commonly associated, and similar underlying inflammatory processes link both diseases. AR, even in the absence of asthma, is associated with increased levels of exhaled nitric oxide (ENO) and hydrogen peroxide (H(2)O(2)) in exhaled breath condensate, 2 noninvasive markers of lower airway inflammation.

OBJECTIVE

We sought to evaluate the effect of treatment with the nasal steroid triamcinolone acetonide on ENO and exhaled H(2)O(2) in subjects with AR.

METHODS

We allocated 23 subjects in a randomized, double-blind, parallel-controlled fashion to 4-week treatment with triamcinolone acetonide (220 microg/d) or matching placebo.

RESULTS

ENO levels were greater in the subgroup with concomitant asthma (16/23 subjects) and decreased significantly with triamcinolone acetonide treatment in this subgroup of patients in comparison with patients receiving placebo. Breath condensate levels of H(2)O(2) were higher in patients with AR without asthma than in those with asthma but decreased significantly with triamcinolone acetonide treatment in both subgroups. No changes were observed in bronchial hyperresponsiveness, nasal and asthma symptoms, or peak expiratory flow with active treatment or placebo.

CONCLUSION

We conclude that treatment of AR with triamcinolone acetonide results in decrease of 2 noninvasive markers of lower airway inflammation, ENO and H(2)O(2), supporting that upper and lower airway inflammation should be seen as a continuum in subjects with AR with and without asthma. ENO might be a more specific marker of the lower airway inflammation present in asthma.

Exhaled nitric oxide in asthma: from bench to bedside

With more than 600 publications, exhaled nitric oxide (NO) has been extensively investigated as a noninvasive marker of airway inflammation in a research setting. This clinical rostrum presents a synopsis of the latest research about this novel marker in asthma and suggests how it might move from bench to bedside. Specifically, we review the evidence citing the applicability of exhaled NO in diagnosing asthma, monitoring the response to therapy, evaluating current symptom control, and predicting exacerbations of asthma. These studies support a role for exhaled NO in the evaluation and treatment of asthma in the clinical arena.

Effect of cat and dog ownership on sensitization and development of asthma among preteenage children

An inverse relationship has been proposed between exposure to high quantities of cat allergen at home and both asthma and cat allergy. First- and second-grade children from Luleå, Kiruna, and Piteå, Sweden participated in an asthma questionnaire study (n = 3,431) and incidence was evaluated over the next 3 years. Skin testing was performed on the children in Luleå and Kiruna (n = 2,149). The strongest risk factor for incident cases of asthma was Type 1 allergy (relative risk [RR], 4.9 [2.9-8.4]), followed by a family history of asthma (RR, 2.83 [1.8-4.5]). Living with a cat was inversely related both to having a positive skin test to cat (RR, 0.62 [0.47-0.83]) and incidence of physician-diagnosed asthma (RR, 0.49 [0.28-0.83]). This effect on incident asthma was most pronounced among the children with a family history of asthma (RR, 0.25 [0.08-0.80]). The evidence also suggests that many of the children exposed to cats at home can develop an immune response that does not include immunoglobulin E. Weaker protective trends were seen with dog ownership. The traditional thinking that not owning cats can provide protection against developing allergy and asthma among those with a family history of allergy needs to be re-evaluated. In a community where cat sensitization was strongly associated with asthma, owning a cat was protective against both prevalent and incident asthma.

A study of the association between exercise-induced wheeze and exercise versus methacholine-induced bronchoconstriction in adolescents

Among asthmatics, exercise-induced wheeze (EIW) is a frequent symptom, and 40-77% of asthmatics demonstrate exercise-induced bronchoconstriction (EIB). In the North-Trøndelag population-based survey of 8,571 adolescents (YOUNG-HUNT), 26% reported wheeze during the previous 12 months (current wheeze). Of those subjects, 50% reported EIW. The aim of the present study was to investigate the association between EIW and EIB in randomly selected adolescents with EIW as the only or predominant asthma-like symptom, and to relate our findings to results from methacholine bronchoprovocation tests (MT) and measurements of exhaled nitric oxide (ENO). Sixty-three subjects with current wheeze induced by exercise, but not by allergen exposure, were investigated using a treadmill exercise test (ET) and measurements of ENO. Fifty-eight subjects completed a MT on a separate study day. EIB was defined as a fall of >or= 10% in the forced expiratory volume in 1 second (FEV1) after exercise (DeltaFEV1%ex). Twenty-one subjects (33%) had EIB and 33 (57%) had a positive MT. The degree of reported dyspnea during the ET was not correlated to the DeltaFEV1%ex. The correlation between EIB and methacholine-induced bronchoconstriction (MIB) was poor, and the DeltaFEV1%ex was more pronounced in smokers than in non-smokers. Moreover, ENO was not increased in subjects with positive vs. negative ET. Hence, EIW, when reported as the only or predominant asthma-like symptom, was linked to EIB in only one-third of the patients. We conclude that EIW is a poor predictor of EIB in epidemiological studies. The poor correlation between EIB and MIB indicates that these two tests measure different mechanisms of bronchial hyper-responsiveness.