Prevalence of skin reactions to aeroallergens in asthmatics of Puerto Rico

Abstract

In Puerto Rico, although a high prevalence of asthma has been reported, the sensitization rates to aeroallergens in these patients is unknown. The purpose of this study using a case control design, was to determine and compare the rates of sensitization to common aeroallergens in an asthmatic population of 576 asthmatics and 144 healthy controls. A skin prick test was conducted using standardized extracts of Dermatophagoides farinae (Df) and D. pteronyssinus (Dp), house dust (HD), cat hair and epithelium (CT), dog hair and dander (DG), grass pollen mix (PG), tree pollen mix (PT), weed pollen mix (PW), Aspergillus mix (AM), mold mixes A (MA) and B (MB), Periplaneta americana (PA) and Alternaria-Hormodendrum mix (AH). In addition, an extract from the domestic mite Blomia tropicalis (Bt) was also used. A wheal > or = 3 mm2 was considered a positive reaction. In addition, a standardized questionnaire was administered and a preliminary domestic mite identification survey was conducted. The analysis of the data showed that 85.8% of the asthmatics had at least one positive reaction and 61.6% of them had positive skin reactions to atleast one mite species. Asthmatics reacted to domestic mites 6.19 times more than the control group (p < 0.0001) and was the largest significant difference found in this study for any allergen tested. Preliminary identification of the acarologic fauna in southern Puerto Rico demonstrated that Blomia tropicalis, Dermatophagoides pteronyssinus, D. farinae and E. maynei are the dominant domestic mite species found in homes of asthmatic individuals. These results demonstrate that domestic mites are a very important source of sensitizing aeroallergens for asthmatic patients in Puerto Rico. Based upon the mite survey, Blomia tropicalis plays an important role in allergic sensitization, in addition to Dermatophagoides pteronyssinus and D. farinae. The skin prevalence to pollens and to molds may not reflect the true prevalence of sensitization to these allergens. Pollen identification and counts, and a survey of microflora of Puerto Rico are needed in order to identify and validate important allergens that eventually could be incorporated into a more appropriate panel for testing sensitization in susceptible individuals.