Sensitization to Blomia tropicalis: skin test and cross-reactivity studies

This study evaluated the prevalence of positive percutaneous skin test results to Blomia tropicalis, Dermatophagoides pteronyssinus, and D. farinae in 167 consecutive persons (61 males, 106 females; mean age, 38.7 years; range, 14 to 75 years) with asthma or rhinitis, or both, in Tampa, Fla. Forty-nine had asthma with or without rhinitis, and 118 had rhinitis alone. RAST and RAST inhibition analysis of all three mite species were performed by using pooled patient sera. Prepared extracts of B. tropicalis and standardized D. pteronyssinus and D. farinae (1:50 wt/vol) were used for percutaneous skin tests. One hundred twelve subjects (67%) had a positive result to at least one mite species; 38%, 62%, and 60% reacted to B. tropicalis, D. pteronyssinus, and D. farinae, respectively. Positive skin test results to both D. pteronyssinus and D. farinae occurred in 96 subjects (57%); 56 of these subjects (58%) were also positive to B. tropicalis. Positive skin test results to B. tropicalis, D. pteronyssinus, or D. farinae alone occurred in four (2%), five (3%), and four (2%), respectively. RAST and RAST inhibition data indicate that B. tropicalis contains unique allergens. The high rate of skin test reactivity to B. tropicalis extracts, and its unique allergenic composition, warrants its use in the diagnosis and treatment of allergic disorders in Tampa.