Contact allergy to Dermatophagoides in atopic dermatitis patients and healthy subjects

To compare different house-dust-mite-derived allergenic materials and to correlate the presence of IgE to Dermatophagoides with patch test results, 313 atopic dermatitis (AD) patients and 100 healthy volunteers (HV) underwent patch tests with: Dermatophagoides pteronyssinus (DPT) lyophilized purified alpha fraction in buffered saline/glycerol 50% and/or in petrolatum (Bayropharm); 50% DPT and 50% Dermatophagoides farinae (DF) whole bodies in petrolatum and petrolatum oil (Allergopharma-Bracco); DPT and DF whole bodies in petrolatum and petrolatum oil (Lofarma). We found 39% positive reactions among AD subjects and 13% in HV. The presence of serum-specific IgE did not influence the patch test results. 38% of AD patch-test-positive patients and 4 of 13 HV, respectively, showed a positive prick test and/or RAST to Dermatophagoides. Similar sensitization rates were observed with the allergenic material from Bayropharm (54% positives) and Allergopharma-Bracco (51% positives), whereas the preparations from Lofarma gave a 20% response rate.