Disseminated superficial actinic porokeratosis is manifested in the third and fourth decade of life by multiple brownish annular keratotic foci mainly on the extensor surfaces of the lower extremities and arms. A typical feature is the histological picture of cornoid lamella. Association of the disease with UV radiation or with immunosusuppression is known as well as a tendency of development of malignity. Treatment remains a problem. The authors investigated the response of porokeratotic lesions to the local application of tacalcitol. After a three-month follow-up the pruritus disappeared and some of the manifestations were paler, while some 50 % foci did not respond to treatment. Long-term experience is needed before final conclusions can be made.

        Key words: porokeratosis superficialis disseminata actinica - tacalcitol