Action of topically applied arachidonic acid on the skin of patients with psoriasis.

ABSTRACT

Concentrations of arachidonic acid ranging from 0.1% to 2% were applied under occlusive dressings to psoriatic plaques in 45 patients. Alleviation of the clinical symptoms of psoriasis including complete clearing in some cases was obtained with the use of 0.5% to 2% arachidonic acid applied under occlusion every 24 to 48 hours five to seven times. Histologic examination showed polymorphonuclear leukocytes penetrating into the stratum corneum and formation of microabscesses or wide-spread accumulations of polymorphonuclear leukocytes in the stratum corneum, with its eventual destruction. The parakeratotic horny layer became detached; this was followed by restoration of the granular layer and an apparently normal stratum corneum. While arachidonic acid metabolites can be proinflammatory and proproliferative, they may also be important in the healing process for psoriasis.