Blomia tropicalis sensitization as a risk factor for the development of allergic rhinitis.

Abstract

Brazil is a tropical country with weather conditions (hot with high humidity) favoring house dust mite growth. Domestic mites are our main aeroallergens and are found widespread in most homes. Both Dermatophagoides pteronyssinus (Dp) and Blomia tropicalis (Bt) are the local predominant mites. Asthma alone without rhinitis has a low prevalence in Brazil, usually of less than 5% of all respiratory atopic cases.1 It has been previously estimated that about 4% of the subjects in Rio de Janeiro with asthma and/or rhinitis had positive allergy skin tests exclusively to Bt.2–3 We followed 26 patients with upper and lower respiratory symptoms. These patients had positive skin tests exclusive to Bt. They were not allergic to the other domestic mites including the pyroglyphid Dermatophagoides pteronyssinus and Dermatophagoides farinae. All of the patients exhibited rhinitis, with or without asthma. We have therefore hypothesized that Bt sensitization could be an additional risk factor for the development of rhinitis. This could explain the low incidence of isolated asthma in Brazil.