Porphyria cutanea tarda
(PCT) is the most common type of porphyria with a prevalence of approximately 1 in 10,000. It is characterized by cutaneous blisters that develop on sun-exposed areas of the skin such as the hands and face. The skin in these areas may blister or peel after minor trauma. Increased hair growth, as well as darkening and thickening, of the skin may also occur. Neurological and abdominal symptoms are not characteristic of PCT. Liver function abnormalities are common, but are usually mild. Progression to cirrhosis and even liver cancer occurs in some patients. PCT is caused by a deficiency of the enzyme uroporphyrinogen decarboxylase. Excess iron and multiple other susceptibility factors, including alcohol, estrogens, smoking, chronic hepatitis C, HIV and mutations in the HFE gene which is associated with the disease hemochromatosis, contribute to the development of PCT. PCT is managed with regular phlebotomies or a low dose regimen of hydroxychloroquine as well as removal of factors that activated the disease. Source: Genetic and Rare Diseases Information Center (GARD), supported by ORDR-NCATS and NHGRI.