Long-term administration of highly purified eicosapentaenoic acid provides improvement of psoriasis.

Nine patients with chronic stable psoriasis (4 males and 5 females) were entered in this trial. Eicosapentaenoic acid (EPA) ethylester (90% pure) without docosahexaenoic acid (DHA) in gelatin-coated capsules at a daily dose of 3.6 g was administered to 9 patients for 3 months, 7 patients for 6 months and 6 patients for 12 months. The clinical changes of skin lesions of the patients with 12 months of treatment were as follows: marked improvement 1, improvement 3, relative improvement 1, no change 1. A clinical improvement of skin lesions was first observed 2-3 months after EPA treatment. The supplementation of highly purified EPA caused a significant increase in the content of plasma EPA and docosapentaenoic acid without affecting that of arachidonic acid (AA) and DHA. EPA decreased the production of leukotriene B4 (LTB4) and increased the formation of leukotriene B5 (LTB5) and 5-hydroxyeicosapentaenoic acid significantly in A23187-stimulated neutrophils. The LTB5/LTB4 ratio positively correlated with the plasma EPA/AA ratio and was directionally related to the clinical score, although the directional data were not statistically significant. We could not observe any side effects of EPA over 1 year. Although its effects are modest, it is nontoxic and its favorable effect appears to continue for the duration of its usage, indicating that EPA could be beneficial for the long-term treatment of psoriasis.