Bathing suit delivery of 8-methoxypsoralen for psoriasis: a double-blind, placebo-controlled study

Twenty-four patients, 15 men and 9 women, aged 18-70 years with stable plaque-type psoriasis involving more than 20% of the body surface were subjected to a randomized, double-blind, age- and sex-matched, placebo-controlled study. Containers containing 25 mL of either 1% 8-MOP or a color-matched placebo were randomly numbered and stored. To 2 L of water was added 0.8 mL of 1% 8-MOP to obtain a concentration of 3.75 mg/L3, into which a bathing suit was soaked for 5 min. The suits were then gently squeezed to remove excess water and the patients were advised to put on the suit covered by a raincoat for 15 min. Immediately after removal of the raincoat and the suit, patients were irradiated with an initial dose of 4 J/cm2 UVA with increments of 0.5 J/cm2 on alternate days in a whole-body phototherapy unit obtained from the National Biological Corporation, Ohio. Erythema, scaling, and thickness (EST) of the index lesions were assessed on a 3-point scale (Table 1) and photographs were taken before and after completion of the study.