Porphyria cutanea tarda
From IDWiki
Definition
- A defect in the heme synthesis pathway that causes cutaneous manifestations in adults
- Either type 1 (sporadic) or type 2 (familial)
Pathophysiology
- A defect in uroporphyrinogen decarboxylase, which normally converts uroporphyrinogen I and III to coproporphyrinogen I and III
Clinical Presentation
- Blistering skin lesions on the back of the hands
- They rupture and crust over, leaving atrophy and scarring
- Scarring and calcification can look like sclerosis
- Lesions may appear on forearms, face, legs, and feet
- May have hyperpigmentation and hypertrichosis of the face
- No neurological manifestations
- Often have liver disease, and are higher risk for hepatocellular carcinoma
Investigations
- Porphyrins in liver, plasma, urine, or stool are elevated
- Urinary porphyrins include uroporphyrins and heptacarboxylate porphyrin
- Urinary ALA level may be elevated
- PBG level is normal
Management
- Avoid alcohol
- Stop estrogen supplements, iron supplements, and any other drugs that may be exacerbating
- Repeated phlebotomy to reduce hepatic iron stores
- Remove 1 unit every 1 to 2 weeks
- Remission may require more than six phlebotomies
- Follow the serum porphyrin levels every 6 to 12 months; they should decrease
- Hydroxychloroquine is second-line
- Liver imaging to screen for hepatocellular carcinoma
