Site of Action of Methotrexate in Psoriasis

Abstract

Methotrexate has little visible effect upon the psoriatic lesion when applied in aqueous cream or ointment under polythene occlusive dressings or when infused into the lesion over a period of three days. High concentrations (1%) in aqueous dimethyl sulfoxide when applied under polythene dressings caused pain, purpura, blisters and erosions in some patients. Less than 0.55% of methotrexate applied epicutaneously with occlusion was excreted in the urine over a period of 72 hours, and most of the methotrexate remained on or in the stratum corneum.