In vivo and in vitro sensitization to domestic mites in German urban and rural allergic patients.

Sensitization to domestic mites is common in Germany. The main objectives of this study were (1) to establish the rate of skin test sensitivity to Dermatophagoides pteronyssinus, Acarus siro, Lepidoglyphus destructor, and Tyrophagus putrescentiae in 512 consecutive patients evaluated for upper and/or lower respiratory complaints; (2) to verify how many of the patients with a positive skin test to at least one of the three storage mites were also skin test positive to D. pteronyssinus; and (3) to verify how many of the patients with at least one positive skin test to one of the storage mites previously mentioned were also sensitized, in vitro, to other mite species. A total of 512 consecutive patients with rhinitis and/or asthma, living in urban or rural areas of central Germany were skin tested with extracts of D. pteronyssinus, A. siro, L. destructor, and T. putrescentiae. In addition, specific IgE determinations to Euroglyphus maynei, Blomia tropicalis, Blomia tjibodas, Blomia kulagini, and Gohieria fusca were conducted in those individuals with a positive skin test to at least one of the storage mites used in skin testing. Of the 512 patients, 103 (20.1%; 77 urban dwellers and 26 farmers) reacted to at least one of the storage mites. From this latter group, 88 individuals (85.4%) also skin tested positive to D. pteronyssinus. In vitro specific IgE determinations revealed a high rate of sensitization to the other mite species studied. We conclude that sensitization to storage mites in Germany is frequently associated with sensitivity to D. pteronyssinus. Overall, skin test sensitivity to storage mites was greater in rural than in city dwellers. In vitro sensitization to B. tjibodas was also significantly greater in rural than in city dwellers.