The influence of atopic status and potential risk factors for sensitization on histamine skin reactivity in unselected Belgian children

Association of body mass index and season with histamine skin reactivity in Chinese children with allergic rhinitis

BACKGROUND

To investigate the association between histamine skin reactivity and body mass index (BMI) and other clinical factors, 526 children (3-6 years old) who underwent a skin-prick test (SPT) to diagnose allergic rhinitis were enrolled.

METHODS

The SPT was carried out using 43 common allergens (commercial kit). The wheal size was analyzed. The associations between histamine reactivity and age, gender, BMI, atopy, parental smoking history, and testing season were examined.

RESULTS

Mean age was 4.6 ± 1.1 years. Among all 526 children, 202 (38.4%) had intermittent allergic rhinitis (IAR), 164 (32.1%) had IAR + persistent allergic rhinitis (PER), and 160 (30.4%) had PER. The size of the histamine skin wheal and maximum diameter for positive allergens showed significant seasonal differences (P = 0.001 and P = 0.02, respectively). Children with biparental allergy history had a higher BMI (P = 0.006). BMI (P < 0.001), summer testing (P = 0.001), and autumn testing (P < 0.001) were independently associated with the size of the histamine skin wheal. Only winter testing was independently associated with the maximal diameter for positive allergens (P = 0.002).

CONCLUSIONS

Higher histamine skin reactivity was associated with higher BMI and summer or autumn testing. Subject BMI and season should be considered for better interpretation of the SPT. The mechanisms underlying these associations require further study.

Histamine skin reactivity increases with body mass index in Korean children

OBJECTIVE

Histamine skin prick testing is most commonly used to diagnose immunoglobulin E (IgE)-mediated allergic diseases, and histamine reactivity is used as a standardized positive control in the interpretation of a skin prick test. However, reactivity to histamine differs among individuals for reasons that are poorly understood. The present study aimed to evaluate the potential association between body mass index (BMI) and histamine skin reactivity in children.

METHODS

A total of 451 children (246 boys, 205 girls) aged 7-8 years were enrolled in this study. The skin prick test was performed with 26 aeroallergens commonly found in Korea. Other information was collected, including sex, age, BMI, parental allergy history, and parental smoking status. Multivariate analysis was used to confirm the association between histamine skin reactivity and BMI.

RESULTS

The histamine wheal size was revealed to be associated with BMI (Spearman's Rho 0.161, p<0.001). This association was confirmed by multivariate analysis, after adjusting for sex, age, parental allergy history, parental smoking status, and allergic sensitization (coefficient B 0.071, 95% confidence interval 0.030-0.112).

CONCLUSIONS

Skin responses to histamine were primarily correlated with increased BMI. Further studies are needed to understand the clinical implication of BMI when interpreting the results of skin prick test.

Skin prick test reactivity to aeroallergens by filaggrin mutation status

BACKGROUND

Studies have shown that filaggrin gene (FLG) mutations are positively associated with sensitization to aero allergens. We hypothesized that FLG mutations would also have an effect on the mean size of positive skin prick test (SPT) reactions as well as the number of positive reactions.

OBJECTIVE

To investigate the effect of FLG mutations on the mean size and the number of positive SPT reactions, as well as the association with positive specific IgE.

METHODS

A random sample of 3335 adults from the general population in Denmark was genotyped for the R501X and 2282del4 mutations in the FLG. SPT and specific IgE measurements to common aeroallergens were also performed.

RESULTS

FLG mutations did not influence the mean size and number of positive SPT reactions. Also, no association was found between FLG mutations and specific IgE measurements.

CONCLUSION

Our findings suggest that FLG mutations alone are insufficient to cause secondary sensitization to allergens. The positive association seen in patients must be explained by a combination of further barrier abnormality caused by dermatitis as well as increased allergen exposure.

Histamine and allergen skin reactivity in the elderly population: results from the Korean Longitudinal Study on Health and Aging

BACKGROUND

The allergen skin prick test is the most representative diagnostic test for atopy, but its use has been limited because of the belief that skin reactivity decreases with aging.

OBJECTIVE

To investigate skin reactivity and influencing factors in the elderly population.

METHODS

This cross-sectional analysis included 854 subjects (aged ≥65 years) who participated in the Korean Longitudinal Study on Health and Aging cohort (September 2005 to August 2006) and underwent allergen skin prick tests. Skin prick tests were performed with 1 mg/mL of histamine and a panel of 12 aeroallergens that are common in Korea. The wheal diameters were measured and compared to identify the factors associated with skin reactivity.

RESULTS

Older age and female sex were associated with reduced histamine skin reactivity in elderly subjects. This age-related decrease was apparent only among women, the reasons for which were not identified. In contrast to histamine, wheal response size induced by 2 major allergens, Dermatophagoides pteronyssinus and Dermatophagoides farinae, did not show sex differences and did not decrease with age among the subjects showing allergen-induced wheal size greater than 0 mm.

CONCLUSIONS

This analysis demonstrates that age and sex can independently influence histamine skin reactivity among the elderly population. The allergen-induced wheal sizes did not decrease with age. The discrepancy between histamine and allergen skin reactivity may warrant further evaluation to redefine the cutoff value for the determination of a positive skin test result in elderly subjects.

Establishing the diagnosis of peanut allergy in children never exposed to peanut or with an uncertain history: a cross-Canada study

The diagnosis of peanut allergy (PA) can be complex especially in children never exposed to peanut or with an uncertain history. The aim of the study is to determine which diagnostic algorithms are used by Canadian allergists in such children. Children 1-17 yrs old never exposed to peanut or with an uncertain history having an allergist-confirmed diagnosis of PA were recruited from the Montreal Children's Hospital (MCH) and allergy advocacy organizations. Data on their clinical history and confirmatory testing were compared to six diagnostic algorithms: I. Skin prick test (SPT) >or=8 mm or specific IgE >or=5 kU/l or positive food challenge (+FC); II. SPT >or=8 or IgE >or=15 or +FC; III. SPT >or=13 or IgE >or=5 or +FC; IV. SPT >or=13 or IgE >or=15 or +FC; V. SPT >or=3 and IgE >or=5 or IgE >or=5 or +FC; VI. SPT >or=3 and IgE >or=15 or IgE >or=15 or +FC. Multivariate logistic regression analysis was used to identify factors associated with the use of each algorithm. Of 497 children recruited, 70% provided full data. The least stringent algorithm, algorithm I, was applied in 81.6% (95% CI, 77-85.6%) of children and the most stringent, algorithm VI, in 42.6% (95% CI, 37.2-48.1%).The factor most associated with the use of all algorithms was diagnosis made at the MCH in those never exposed to peanut. Other factors associated with the use of specific diagnostic algorithms were higher paternal education, longer disease duration, and the presence of hives, asthma, eczema, or other food allergies. Over 18% (95% CI, 14.4-23.0%) of children were diagnosed with PA without fulfilling even the least stringent diagnostic criteria.

Messages from the Aalst Allergy Study

BACKGROUND

The prevalence of sensitization and allergic disease has increased significantly worldwide. The aim of the "Aalst Allergy Study" was to document prevalences of sensitization and allergic symptoms, and to evaluate the effect of personal and environmental influences on these prevalences in an unbiased Belgian pediatric population.

METHODS

A cross-sectional study was performed in an unbiased population of 2021 Belgian schoolchildren (3.4-14.8 years). Skin prick testing with the most common aeroallergens was performed. Allergic symptoms as well as potential risk factors for sensitization and allergic disease were documented by a parental questionnaire.

RESULTS

The prevalence of sensitization to the most common aeroallergens and the prevalence of allergic diseases (eczema, asthma and rhinoconjunctivitis) were in line with the data in the literature. The association of current allergic symptoms with sensitization was only significant in the children aged > or =6 years. Age, gender, body mass index, bedroom environment and exposure to pets were the factors significantly associated with sensitization and allergic symptoms.

CONCLUSIONS

Our study corroborates the reported prevalences of sensitization and allergic diseases. Moreover the study illustrates the complexity of the search for factors involved in the process of sensitization and allergic disease. The impact of different potential causative factors is not only influenced by mutual interactions of these factors, but also by the existence of distinct subtypes of disease.

Body mass index in Belgian schoolchildren and its relationship with sensitization and allergic symptoms

Results of studies of the influence of body mass index (BMI) on the allergic status are controversial. As a part of the Aalst Allergy Study, we assessed the prevalence of the different BMI categories (underweight, normal weight, overweight, and obesity) and a possible association between BMI and atopy in 1576 unselected Belgian schoolchildren, aged from 3.4 to 14.8 yr. BMI was used to determine weight status. Skin prick testing with the most common aeroallergens was performed. A parental questionnaire documented data on respiratory and allergic disorders, demographic characteristics and other potential risk factors for sensitization. Among the total children, 4.1% of the children were underweight, 14.5% were overweight, and 7.4% were obese. More girls than boys were overweight (p = 0.015). In the group of children older than 12 yr, we found more overweight (p = 0.03) and obese (p = 0.004) girls, and more obese boys (p = 0.004) than in the younger age groups. In contrast with reports in the literature, an increased prevalence of allergic sensitization in underweight girls only [adjusted odd ratio (OR(adj)) = 2.9, 95% confidence interval (CI): 1.3-6.4] was documented. A strong association between obesity and exercise-induced respiratory symptoms was found in both boys (OR(adj) = 14.5, 95% CI: 2.9-73.3) and girls (OR(adj) = 4.9, 95% CI: 1.3-17.4). No correlations with allergic respiratory symptoms, eczema, or rhinoconjunctivitis could be documented.