Comparison of the Skin Test and ImmunoCAP System in the Evaluation of Mold Allergy

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.

Key Words:  allergen , fungi , intradermal tests , rhinitis

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