Hepatoerythropoietic porphyria in Adult
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.
E80.20 – Unspecified porphyria
111386004 – Homozygous porphyria cutanea tarda
Differential Diagnosis & Pitfalls
- Porphyria cutanea tarda – This is caused by a partial defect or suppression of the same gene mutation as HEP but typically presents later in life.
- Other blistering cutaneous porphyrias – HEP may be confused clinically with variegate porphyria, hereditary coproporphyria, or congenital erythropoietic porphyria. These other blistering cutaneous porphyrias have similar sun sensitivity but have distinct patterns of porphyrin elevation.
- Nonblistering cutaneous porphyrias – HEP is less likely to be confused with erythropoietic protoporphyria and X-linked protoporphyria. Nonblistering porphyria is characterized by burning instead of skin blisters on sun exposure and is not associated with an increase in urine porphyrins.
- Systemic lupus erythematosus
- Polymorphous light eruption
- Inherited epidermolysis bullosa
- Systemic amyloidosis
- Phototoxic drug reaction