PURPOSE OF THE STUDY.
The goal of this study was to test the yield of skin prick testing (SPT) versus allergen-specific serum IgE (sIgE) testing at identifying aeroallergen sensitization in atopic children aged <4 years.
The study population consisted of 40 atopic inner-city children from a pediatric asthma center in the Bronx, New York, aged <4 years who had a history of wheezing. Patients were enrolled in a randomized, prospective interventional clinical trial evaluating the efficacy of subcutaneous immunotherapy in asthma.
Children with wheezing on >1 occasion, atopy, and having a major risk factor for developing asthma (ie, family history of eczema and/or asthma) were included in the study. The patients underwent SPT for 7 common aeroallergens, including grass pollen mix, ragweed pollen, dust mite, roach, mouse, cat, and dog. The children with both SPT and parental consent to participate in an associated clinical immunotherapy trial had sIgE levels performed by the Immulite System (Siemens AG, Munich, Germany) within 4 weeks of initial SPT testing.
Poor to fair agreement between the 2 methods of detecting allergic sensitization existed for all food allergens tested, except mouse, which had moderate agreement. If only SPT had been performed, 42% of the sensitizations diagnosed by using combination SPT and allergen-specific sIgE level would have been missed. In contrast, 13% of missed sensitizations were seen when allergen-specific sIgE alone was performed. Further investigation showed that at least 1 specific aeroallergen sensitization would have been missed in 80% of children who only underwent SPT. In addition, more than one-third of children in this study would have had ≥1 aeroallergen sensitization missed by undergoing allergen-specific sIgE testing alone. SPT and allergen-specific sIgE were a perfect match only in 7.5% (3 of the 40 children). Children with high total sIgE levels (≥300 kU/L) were more likely to have negative results on SPT in the face of sIgE-positive tests to the same allergen. They were also less likely to have SPT-positive results in the face of sIgE-negative test results to the same allergen.
The results of this study suggest that when testing for aeroallergen sensitization, both forms of testing (SPT and sIgE) should be considered to make the diagnosis in children aged <4 years with high risk for asthma.
This study suggests that some young patients would likely benefit from both SPT and sIgE testing. One limitation to the study, however, is the sample size. This study reminds us that when results of laboratory tests do not support the clinical diagnoses we suspect, further testing may help make the proper diagnosis in some cases. Further randomized controlled studies with larger sample sizes are needed to investigate the utility of both tests in the diagnosis of young children at high risk for asthma.
- Copyright © 2014 by the American Academy of Pediatrics