Long-term effect of high-dose, short-course chloroquine therapy on porphyria cutanea tarda.
Forty-six patients with porphyria cutanea tarda were observed for a mean period of 32 months (range 4-86) after treatment with high-dose, short-course chloroquine phosphate. There was early improvement in the cutaneous manifestations except in exposed parts with with the hyperpigmentation and hypertrichosis which improved more slowly (3-6 months). Mean serum transaminase and mean urinary porphyrin levels remained below the pre-treatment values. There was no deterioration of liver function in any of the group treated with chloroquine and the underlying liver disease followed the usual independent course. Only six patients (13 per cent) relapsed. Considering the immediate effectiveness, good compliance, safety, lasting remission and low rate of relapse with prompt response on further treatment, high-dose, short-course treatment with chloroquine should be considered as the treatment of choice in porphyria cutanea tarda.