Treatment of atopic eczema with evening primrose oil: rationale and clinical results.

Recently a defect in the function of the enzyme delta-6-desaturase has been discussed as a major factor in the development of atopic eczema. Delta-6-desaturase is responsible for the conversion of linoleic acid to gamma linolenic acid. Several plants, including evening primrose, are known to be fairly rich in gamma linolenic acid. Hence, substitution of gamma linolenic acid in patients prone to developing atopic eczema seems like a feasible concept. During the last few years different clinical trials have been performed. Controlled trials following a parallel study design showed marked improvement in atopic eczema. Patients treated with the drug showed less inflammation, dryness, scaling and overall severity compared to controls. Although these findings have been supported by meta-analysis, there is still conflicting evidence in trials based on a crossover design alone, demonstrating a decrease in itching. At present, evening primrose oil in doses used for the treatment of atopic eczema is considered safe. However, still more trials addressing both efficacy and safety are needed to make a final decision.