Variegate porphyria - Skin
The exact pathogenesis of the acute attacks is poorly understood. It is thought that certain porphyrin precursors – such as aminolevulinic acid and porphobilinogen – that are excreted by the liver in high amounts during attacks are potent neurotoxins.
Porphyrinogenic drugs, alcohol, hormonal changes, recurrent or chronic infections, and fasting or dieting (specifically carbohydrate restricting) may all precipitate an acute attack. Hepatic cytochrome p450 enzymes utilize heme as a cofactor; thus medications degraded by the body through induction of these enzymes may accelerate heme synthesis and accumulation of the neurotoxic porphyrin precursors in these patients, thereby precipitating an acute attack. Such medications include barbiturates, estrogen, griseofulvin, and sulfonamides, among others.
There is a high incidence of the condition in Afrikaners from South Africa.
Pediatric Patient Considerations:
Onset typically occurs after puberty.
For more information, see OMIM.
E80.20 – Unspecified porphyria
58275005 – Variegate porphyria
- Porphyria cutanea tarda (PCT) – lacks the acute systemic findings, is more easily provoked, and presents with severe cutaneous findings. In variegate porphyria, the ratio of uroporphyrins to urinary coproporphyrin is usually 1:1 (or uroporphyrins < coproporphyrin), whereas in PCT, the ratio of uroporphyrins to urinary coproporphyrin is 3-8:1
- Acute intermittent porphyria – lacks cutaneous findings
- Other acute porphyrias – hereditary coproporphyria, d-aminolevulinic acid (ALA) dehydratase deficiency porphyria