Porphyria Cutanea Tarda

  • General Information
    • Most common type of porphyria; prevalence is 1 in 25,000 in the United States.
    • Due to deficiency in uroporphyrinogen decarboxylase (UROD) which participates in heme synthesis.
    • Deficiency causes buildup of uroporphyriogen in the urine.
  • Clinical Manifestations:
    • Typically presents later in life (age > 30) and characterized by chronic blistering skin in sun-exposed areas.
    • Lesions are thought to be due to buildup of uroporphyrinogen on the surface of skin; exposure to sunlight is thought to produce reactive oxygen species leading to skin changes.
    • Considered a highly heterogeneous disease with multiple factors contributing to disease susceptibility: alcohol, hepatitis C, HIV, hemochromatosis
    • PCT is thought to be an iron-dependent disease
  • Diagnosis
    • Definitive diagnosis by biochemical testing including predominance of uroporphyrin and heptacarboxyl porphyrins in urine and/or plasma.
  • Treatment
    • Repeated phlebotomy
    • Low dose hydroxychloroquine
    • Iron chelation
    • Cessation from alcohol and smoking
    • PCT should not delay treatment of HIV. Typically PCT is treated first and then hepatitis C is treated.