Study Finds Asthma Severity is Not Associated With Reactivity to Allergen Skin Testing
The findings also show that skin testing positivity for perennial allergens was higher in patients with childhood-onset asthma compared with those with adult-onset asthma.
Research published in Allergy & Asthma Proceedings suggests that patients with early-onset asthma were more likely to have allergies determined via skin test than those with late-onset asthma. Similarly, the perennial skin test reactivity was shown to be higher in early-onset asthma than in late-onset; however, that pattern was not consist with seasonal allergies.1
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Asthma and allergic rhinitis are considered to be pathologically interlinked conditions, and despite skin testing being significant in the assessment of individual allergic sensitization, US data is lacking on skin testing reactivity patterns in patients with asthma. For this study, 500 adult and pediatric patients with asthma were randomly selected from the National Jewish Health electronic medical record over a period of 3 years. Demographic, clinical, and allergen skin testing reactivity data for a total of 10 seasonal (eg, trees, grasses, weeds) and perennial allergens (eg, dust mite, animal dander, cockroaches) were recorded. According to the investigators, 398 of the enrolled 500 were included in the final analysis. Of these patients, approximately 63.3% were women, 50.1% had developed asthma during adulthood, and 86.1% also had rhinitis.1,2
Additionally, data were evaluated based on immunoglobulin E (IgE) levels; the development of asthma during childhood versus adulthood; and asthma severity based on the patients’ sex, race, and corticosteroid use. Data were assessed with the use of t-tests, χ2 tests, and Analysis of Variance (ANOVA). Additionally, patterns of reactivity were assessed for overall, seasonal, and perennial allergens in relation to IgE levels, asthma onset, and severity.2
According to the study findings, approximately 75.3% of patients had tested positive to at least 1 of the 10 allergens, with men showing a higher overall (p = .039) and perennial (p = .035) sensitivity to the allergens. Additionally, skin testing reactivity had varied based on the patients’ rhinitis status for seasonal allergies (p = .028); however, this was not the case for perennial allergens (p = .0733). In patients with childhood-onset of asthma, skin testing positivity for perennial—but not seasonal allergens—was higher than in patients who developed asthma in adulthood, despite both groups having a large proportion of reactors. The investigators also observed that elevations in IgE levels were correlated with skin testing reactivity.2
“This report presents one of the most comprehensive evaluations of skin test reactivity among asthmatics in relation to a wide variety of factors,” said senior author Rohit Katial, MD, allergist and immunologist at National Jewish Health, in a news release. “By looking at all permutations and levels of asthma severity, these findings underscore that a significant majority of asthma patients also manifest allergic rhinitis.”1
The authors note that the study represents a distinctive and comprehensive assessment of skin testing reactivity within US pediatric and adult asthma populations. Additionally, they emphasize that this area is underrepresented in research, particularly when asthma onset, severity, and IgE levels are taken into consideration. The findings highlight the need of allergen sensitization in asthma populations; however, this is important regardless of the severity of asthma, simultaneous rhinitis symptoms, or onset of asthma, according to the authors. Further, the authors believe that these factors can challenge some common and prevailing assumptions about the relationship between asthma onset and sensitization of allergens.2
“It was noteworthy that a previously held assumption that late-onset asthmatics tend to be non-allergic is incorrect,” said Katial in the news release. “Almost 2-thirds of the subjects in the late-onset group had skin test reactivity, suggesting that allergic disease should not be discounted even in late-onset asthma patients.”1
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