In a prospective open study, seven patients with persistent pustulosis palmaris et plantaris were treated with oral Cyclosporin A (CsA). Clinical efficacy was assessed on a semi-quantitative 0-4 point scale for erythema, desquamation, induration and pustulation. CsA controlled skin lesions in doses ranging from 1.1 to 6.1 mg/kg body weight/day. Clinical side effects included renal impairment, nausea and tiredness. Rapid recurrence of the skin lesions was observed on withdrawal or insufficient treatment with the drug.