Porphyrias are a group of diseases resulting from defects / dysfunction in enzymes involved in heme biosynthesis. Several porphyrias have cutaneous features. Porphyrias with blistering cutaneous features include porphyria cutanea tarda and hepatoerythropoietic porphyria (HEP). Porphyrias with nonblistering cutaneous features include erythropoietic protoporphyria and X-linked protoporphyria. Porphyrias that can have both blistering cutaneous features and acute neurovisceral attacks include hereditary coproporphyria and variegate porphyria. Porphyrias with only neurovisceral symptoms without skin findings include acute intermittent porphyria and delta-aminolevulinic acid (ALA) dehydratase deficiency porphyria.

HEP is an extremely rare autosomal recessive form of chronic hepatic porphyria, with approximately 40 reported cases. HEP is caused by mutation of both uroporphyrinogen decarboxylase (UROD) alleles (eg, homozygous or compound heterozygous mutations) and results in excess uroporphyrin in the liver and urine. HEP is disfiguring and is characterized by photosensivity (delayed), bullae on sun-exposed skin (face, hands, forearm, neck, back, feet), skin fragility, hypertrichosis, scarring, "pseudoscleroderm" features (ie, scarring, contracture, and calcification), itching, and red urine. Other commons signs include hyperpigmentation and splenomegaly. Onset is typically during infancy and early childhood. Life expectancy appears to be normal.