Immediate and delayed hypersensitivity to mite antigens in atopic dermatitis

Atopic dermatitis (AD) is a common disorder and appears to be on the increa se, especially among children. It was thought at first to be a manifestatio n of immediate hypersensitivity, but it is now known that delayed hypersens itivity also plays an important role, Sensitivity to mite antigens is found in 20% to 60% of patients when immediate hypersensitivity is evaluated by the detection of specific IgE antibodies and prick tests, and in 30% to 50% of patients when delayed hypersensitivity is studied by patch testing. A p rospective randomized study was carried out in the pediatric dermatology cl inic on a sample of 51 children under 15 years of age. A prevalence of imme diate and delayed hypersensitivity to mites, like that described for other populations, was found. It was further found that there was a positive asso ciation, not described in the literature, between the younger age groups an d delayed hypersensitivity to mite antigens, while the opposite was true fo r immediate hypersensitivity. We believe that patch tests with airborne all ergens, specifically mites, should be part of the protocol for assessing ch ildren with AD, particularly in the younger age groups.