L’Alcool et la peau (éthylisme) – Porphyrie Cutanée Tardive (PCT) (Pour les professionnels)

Porphyria Cutanea Tarda (PCT)

• All porphrias are hereditary except PCT type I
• PCT type I also as symptomatic protoporphria

• Epidemiology: affects males from 40 onwards, often with a history of alcohol abuse
• Three categories

1. PCT I: symptomatic protoporphyria, non hereditary, 80% of PCTs, deficit in uroporphrinogen decarboxylase (only in hepatocytes)
2. PCT II: : autosomal dominant, less than 20% of PCTs, the deficit in uroporphyrinogen decarboxylase is also present in red blood cells.
3. PCT III: similar to PCTI in the sense that uroporphrinogen decarboxylase is only present in the hepatocyte (less than 5% of PCTs), but hereditary

• Clinically

1. skin hyperfragility
2. serous-hemorrhagic bullae and erosions on dorsum of hands following minimal trauma
3. actinic bullosis: light-coloured bullae appearing after sun exposition. Then erosions form leaving scars with milia.
4. hypertrichosis: mostly in malar area
5. chronic actinic dermatosis: premature aging of the skin=diffuse brownish pigmentation, losangeal skin on the nape of the neck (nuchae rhomboidalis), diffuse elastoma and elastosis with cysts, comedones on the face.
6. in 1/3 of cases, scleroderma-like lesions appear lately on the face, neck, torso, trunk and scalp (scarring alopecia beginning from the hairline). In the preauricular area, these lesions calcify (microliths) and the ulcers they create only heal after they disappear.

• Diagnosis

1. dark urine (dark beer or Coca Cola) intensely fluorescing under wood’s light due to high porphyrin content. Uroporphrin is the mostly present followed by heptacarboxylic porphyrin and coproporphyrin.
2. stools: isocoproporphyrin which is not present in other porphyries except the hepato-erythropoietic porphyria.
3. labs also show elevated liver function tests (transmaninases), elevated iron and ferritin levels. Not unfrequently, elevated glycaemia.

• Histology

1. the hyperfragility bulla is sub-epidermal in the papillary dermis. On the floor, the papillae are conserved and have a saw-toothed appearance. There is no inflammatory reaction. Elastosis often present.
2. immunofluoresence shows IgG4, IgM and C3 thick deposits in the dermo-epidermal junction or around superficial dermal vessels.

• Cause: the diminution of 50% of the the activity of uroporphyrinogen-decarboxylase. The cause of the increase of of iron is not known.

• Treatment

1. alcohol withdrawal
2. no hepatotoxic substances
3. balanced diet: rich in proteins and phospholipids, poor in cholesterol.
4. photoprotection (UVB and UVA)
5. blood letting: 300-500cm3 of blood every week for a volume of 2-4 litres. Satisfying results in a few weeks. The mode of action is unknown and it also normalizes iron levels. Surprisingly the usage of deferoxamine mesilate is less effective.
6. chloroquine: 100mg twice weekly (136 g of chloroquine sulfate) enables control achieved with higher doses but no side effects.
7. alcalinisation of urine=not any more

Bibliography: Dermatologie et Infections Sexuellement Transmissibles, 4th Edition