Porphyria cutanea tarda (PCT) is a form of long-term porphyria characterised by fragile skin and sore blisters in areas of skin that receive higher levels of exposure to sunlight, such as the face and backs of the hands. These blisters burst easily resulting in erosions, crusts, and superficial ulcers. There is often associated darkened skin color and extra facial hair growth. Healing is typically slow, leading to scarring and milia, while changes such as hair loss, and alterations in nails may also occur. A slightly purplish tint may be seen around the eyes. Scleroderma-like thick skin may develop over fingers, scalp, behind the ears, at the back of the neck, or in the front of the chest. The urine may appear dark. Unlike other porphyrias, PCT does not cause severe illness.
The disorder results from a deficiency of uroporphyrinogen III decarboxylase, used in the production of heme, a vital component of hemoglobin. It is generally divided into three types; familial, non-familial, and acquired. The condition can be related to liver disease and a history of excessive alcohol consumption. It is a recognised complication of hepatitis C. Other associated conditions include type 2 diabetes, metabolic syndrome, HIV, SLE, and haemochromatosis. Smoking, and the use of estrogen in males with prostate cancer and females on combined contraceptive pill may also trigger PCT. Renal dialysis may cause retention of porphyrins and cause PCT.
