porphyrias

see also:

• acute intermittent porphyria (AIP)

• porphyrias (Gk: purple) are a group of mainly hereditary conditions affecting heme metabolism resulting in accumulation and increased excretion of porphyrins and their precursors
• all are autosomal dominant except for congenital erythropoietic porphyria (CEP), which is autosomal recessive
• rarely it may be acquired:
  • during 1955-1959, ~4000 people in southeast Anatolia developed porphyria due to the ingestion of hexachlorobenzene (HCB), a fungicide that was added to wheat seedlings

• porphyrias can be grouped into acute or chronic

• periodic acute attacks of neurovisceral symptoms
• Doss porphyria
  • extremely rare
• acute intermittent porphyria (AIP)
  • characterised by acute epigastric pain lasting days, peripheral neuropathy, autonomic neuropathy and CNS problems
• hereditary coproporphyria
  • an acute hepatic porphyria that is characterized by abdominal pain, neuropsychiatric symptoms, and cutaneous photosensitivity
• variegate porphyria
  • chronic blistering skin lesions
  • photosensitive skin disease and a propensity to acute neurovisceral crises
  • esp. common in Sth Africa

• chronic dermatologic diseases that may or may not involve the liver and nervous system
• congenital erythropoietic porphyria (Gunther disease)
  • least common porphyria
  • haemolysis may be a feature in homozygous cases
  • prolonged exposure to sunlight may precipitate a blistering rash, red urine, and even blindness
• erythropoietic porphyria
  • photosensitivity, insignificant hematologic abnormalities, and liver disease
  • up to 5% develop fatal hepatic failure
• porphyria cutanea tarda
  • 3 types with typical skin manifestations
  • skin fragility, erosions, vesicles, bullae, and milia in sun-exposed areas