Pustulosis palmo-plantaris. Clinical and histological changes during etretin (acitretin) therapy.

We examined the clinical and histological effects of etretin in pustulosis palmo-plantaris (PPP) in a multicentre study. 30 patients with PPP were treated with etretin in a double-blind study. After a 4-week interval of either etretin (50 mg/day) or placebo (randomized), all patients received etretin during a second period of 20 weeks (the dosage was individually varied). The effect of etretin was verified clinically and by immunhistochemical methods. The number of pustules in a 4 cm2 reference area diminished within the first 4 weeks from 8.5 to 1.9 (etretin group) and from 9.0 to 6.2 (placebo group). Within a maximum of 24 weeks 16% of the patients showed a complete remission, 44% a pronounced improvement, and 22% little improvement. The state of 2% of the patients deteriorated. Immunhistologically, the number of granulocytes was reduced in the inflammatory infiltrate and in the pustules. Etretin is therefore a retinoid, which is easily controlled and effective in PPP.