Effect of dithranol treatment on arachidonic acid and its lipoxygenase products in psoriasis

The concentrations of arachidonic acid and its lipoxygenase metabolites were measured in exudates from lesional psoriatic skin during treatment with 0.25% dithranol (anthralin) applied topically for 10 days. Dithranol caused a reduction in the concentration of arachidonic acid at 10 days (167 +/- 42 and 358 +/- 55 ng ml-1 treated and control sites respectively, p less than 0.05) concurrent with clinical improvement of the lesions. Neither 12-hydroxyeicosatetraenoic acid nor leukotriene B4 concentrations were significantly affected. These results do not support the view that lipoxygenase products are of major importance in the pathogenesis of psoriasis.