Topical administration of 1,25-dihydroxyvitamin D3 for psoriasis: report of five cases.

The effects of topical administration of 1,25-dihydroxyvitamin D3, as 0.1 and 0.5 microgram per g base, and control base applied to contralateral skin lesions in five patients with persistent psoriasis were compared. In all five, definite and in some cases remarkable improvement of the lesions was seen when 1,25-dihydroxyvitamin D3 at concentration of 0.5 microgram per g base was applied for two to five weeks. No local or systemic toxicity was detected in any patient. Although the mechanism of the improvement is yet to be elucidated, these results show the possible effectiveness of topical 1,25-dihydroxyvitamin D3 on psoriatic skin lesions.