Atopic dermatitis: studies of skin permeability and effectiveness of topical PUVA treatment

Ultraviolet light is effective treatment for patients with atopic dermatitis that is resistant to conservative therapy, or complicated by adverse effects of extended steroid use. We designed a protocol using topical psoralen chemotherapy with ultraviolet A (PUVA) to treat atopic dermatitis in 114 patients. Clinical results were excellent, with complete clearing in 50% of patients receiving daily treatment. Histologic and immunologic values correlated with the clinical response, including reduced epidermal thickness, and decreased numbers of epidermal Langerhans cells and dermal mast and mononuclear cell infiltrates. The pattern of keratin 14-positive keratinocytes returned toward normal. In addition, the water-holding capacity of the stratum corneum increased to near normal levels. We also studied stratum corneum permeability in lesional and nonlesional skin using the dimethyl sulfoxide whealing test and theophylline absorption studies. Compared with controls, permeability was markedly increased in lesional skin and mildly increased in nonlesional skin in patients with atopic dermatitis. These results suggest that immune abnormalities and barrier dysfunction participate in the pathogenesis of atopic dermatitis.