HOUSE-DUST MITE ANTIGEN EXPOSURE OF PATIENTS WITH ATOPIC-DERMATITIS OR PSORIASIS

We studied the amount of house dust antigen in the beds of 55 patients with atopic dermatitis, eleven patients with psoriasis and ten health y volunteers using a commercial ELISA which can determine the amount o f antigen from Dermatophagoides pteronyssinus, D. farinae and D. micro seras expressed as nanogram (ng) antigen per gram of house dust. The W orld Health Organization has indicated that 10,000 ng house dust mite antigen per gram house dust can elicit an asthma attack in IgE-sensiti zed patients with asthma bronchiale. There are no recommendations for patients with atopic eczema. We observed no statistical significant di fferences between each group concerning the amount of house dust found in the beds or the amount of house dust mite antigen. However, there mere very wide variations. Twenty-seven percent (15/55) of patients wi th atopic dermatitis add 27% (3/11) of psoriasis patients had levels o f house dust mite antigen above 10,000 ng per gram of house dust compa red with healthy volunteers (1/10). Half of the patients had a type I allergy to house dust mite antigen using prick tests. This group had a total serum IgE of 2,034 kU/I (median value) compared to 301 kU/I in the group without type I allergy to house dust mite antigen (p < 0.01) . The exposure to house dust mite antigen was similar in the two group s. We conclude that only 1/4 of patients with atopic dermatitis are ex posed to high levels of house dust mite antigen in their bed environme nt equal to what is found for patients with another scaling disorder ( psoriasis). Patients,who have an increased serum IgE have significantl y increased type I allergy to house dust mite antigen even though thei r exposure is not different from patients with low IgE.