Cockroach hypersensitivity in asthmatic patients.

Hypersensitivity to cockroach antigen has been recognized as an important cause of perennial allergic rhinitis and asthma. To assess the frequency of cockroach hypersensitivity in our country, 150 asthmatic atopic subjects were studied using skin testing and in vitro assays for cockroach-specific IgE antibodies (Oriental and German cockroaches). Twenty-two of 61 patients who had a positive history of cockroach exposure had positive skin tests, and only 3 of 89 patients who had no history of exposure had positive skin reactions. Of 25 patients with positive skin tests, 23 showed specific IgE antibodies against oriental and German cockroaches using RAST and EIA techniques. In summary, approximately 15% of asthmatic atopics in Madrid area are sensitive to cockroaches (positive skin test + specific IgE antibodies). These results indicate that cockroach hypersensitivity should be considered in every patient with perennial asthma.