Background: Mold is ubiquitous in our environment and is a common allergen in allergic diseases. The skin test and the Pharmacia ImmunoCAP system (CAP) for assay-specific immunoglobulin E (IgE) antibodies are both widely used. The goal of this study was to compare the performance of the skin test and CAP in the evaluation of mold allergy.
Methods: Patients with allergic rhinitis were enrolled at our outpatient department. The diagnosis of allergic rhinitis was based on typical symptoms for more than 2 years. All patients were tested by both intradermal skin test and serum assay for specific IgE antibodies. The skin test included house dust, cotton, ragweed, and 5 fungal antigens (Candida, Alternaria, Aspergillus, Cladosporium, and Penicillium). The serum-specific IgE antibodies were quantified using the radioimmunoassay version of CAP.
Results: Seventy-five patients (44 males and 31 females) with allergic rhinitis were enrolled in this study. Their ages ranged from 12 to 76 years old, with a mean of 31.9 years. The positive rates of skin test and CAP were 56.0% versus 9.3% for Candida, 22.7% versus 1.3% for Alternaria, 16% versus 9.3% for Aspergillus, 14.7% versus 1.3% for Cladosporium, and 32% versus 8% for Penicillium. There were statistically significant differences between the positive rates for Candida, Alternaria, Cladosporium, and Penicillium when analyzed by the McNemar test.
Conclusion: The positive rate of the skin test is higher than CAP when evaluating mold allergy. Clinicians should note that a discrepancy may exist between the results of in vitro and in vivo tests when evaluating mold allergy.