Porphyria cutanea tarda.

Porphyrias are a group of rare metabolic disorders in which excessive quantities of porphyrins, or their precursors, are produced. They are due to specific enzyme deficiencies resulting in abnormalities in the control of the porphyrin-haem metabolic pathway. Porphyria cutanea tarda (PCT) is the most common of all the porphyrias. However this condition is rarely seen in our Asian countries. We describe a patient with PCT who presented clinically with blistering eruptions over the sun-exposed areas. Coral pink fluorescence of uroporphyrins in an acidified urine specimen is diagnostic. Definitive treatment involves the use of low-dose chloroquine and interval venesection.