Skin test reactivity to indoor allergens as a marker of asthma severity in children with asthma.

BACKGROUND: Specific IgE responses to common indoor aeroallergens in children with asthma have been found to be associated with acute asthma.

OBJECTIVE: The purpose of this study was to examine the association between asthma severity and skin test reactivity to four common indoor allergens.

METHODS: The charts of 139 asthmatic children, aged 5 to 18 years, seen in a pediatric allergy clinic were reviewed to obtain the results of skin tests to cat, dog, cockroach, and dust mite allergens, FEV1, anti-asthma medication requirements and demographic characteristics. Logistic regression for ordinal data was used to examine the association between skin test reactivity and asthma severity (mild, moderate or severe) as determined from FEV1 and medication usage.

RESULTS: The rate of allergen sensitivities were dust mite 55%, cockroach 50%, cat 29% and dog 17%. Children with positive skin test to cat allergen were more likely to have a higher asthma severity rating than children with a negative cat allergen skin test [proportional odds ratio (OR) = 3.0, 95% confidence interval (CI) = 1.4 to 6.1, P = .003]. This association remained significant after we controlled for skin test reaction to the other three allergens and various sociodemographic factors (adjusted OR = 3.0, 95% CI = 1.3 to 7.2, P = .013). The ORs for sensitivity to dog, cockroach, and dust mite allergen did not differ significantly from one, but children who were sensitized to all four allergens had an OR of 4.8 (95% CI = 1.3 to 18, P = .019) relative to children who were not sensitized to any of the four allergens. This association also remained significant after controlling for sociodemographic variables (P = .030).

CONCLUSION: Children with combined sensitivity to cat, dog, dust mite, and cockroach allergens were at increased risk of having more severe asthma. Our data also suggest that sensitization to cat allergen per se is a risk factor for more severe disease in these asthmatic children.