Distribution of Dermatophagoides spp., D. farinae and D. pteronyssinus, Antigen in Homes of Patients with Asthma in Eastern Massachusetts

Regional analysis of dust mite species distribution is pertinent to clinical practice as atopic patients should be tested and, when indicated, receive appropriate immunotherapy with house dust mite antigens indigenous to their geographic locale. Surveys in selected areas of the United States have found D. farinae and D. pteronyssinus to be the two most prevalent mite species. None of these surveys encompassed the populous Northeastern corridor of the United States. This present study describes the distribution of Dermatophagoides spp. antigens within the homes of asthma sufferers living in suburban Massachusetts. A total of 60 dust samples were collected from carpets in the homes of 46 patients with chronic asthma and documented house dust mite sensitivity. Dust samples were obtained from bedroom carpets in 46 homes and both bedroom and family room carpets in 14 homes. Dermatophagoides spp. bedroom carpet levels ranged from 2.3 g/g to 138.5 g/g; (mean level 36.1 g/g). D. farinae was the dominant species in the majority (78%) of sampled homes. D. pteronyssinus predominated in only three (7%) homes. Nearly 80% of surveyed homes had carpet dust mite antigen levels exceeding 10 g/g. Mean bedroom carpet levels were more than two-fold higher than family room levels, 47.7 g/g versus 19.5 g/g. Distribution patterns of D. farinae and D. pteronyssinus in bedroom and living room carpets was similar in 13 of 14 surveyed homes. Although D. farinae is clearly the dominant allergen in the surveyed homes, this study suggests that both D. farinae and D. pteronyssinus antigens should be used for diagnostic testing and, when indicated, immunotherapy in the northeastern United States.