Erythropoietic Protoporphyria (EPP)

Etiology
  • ↓Ferrochelatase
    • Lead inhibits ferrochelatase (and ALA dehydratase) leading to:
      • Sideroblastic anemia
      • Coarse basophilic stippling of erythrocytes
      • Headache, nausea, memory loss
      • Abdominal pain, diarrhea (lead colic)
      • Lead lines in gums
      • Lead deposits in abdomen and epiphyses of bone seen on radiograph
      • Neuropathy (claw hand, wrist drop)
      • Increased urinary AA
      • Increased free erythrocyte protoporphyrin)
 
Mechanism
  • Not water soluble → liver deposition → gallstones and pancreatitis;
    • Risk of cholestasis and liver failure
 
Epidemiology
  • Most common childhood porphyria
 
Clinical presentation
  • Photosensitivity syndrome
    • Erythema, edema, hemorrhagic crusts on the nose and fingers
    • Scars on the nose and linear scars on the upper lips
  • Persistent chronic lesions
    • Scars
  • Cholestasis and liver failure (lipid soluble)
 
Diagnosis
  • Fluorescence of erythrocytes
    • If ↓ferrochelatase or ↓iron, Zn can join protoporphyrin giving it a fluorescent halo around the red blood cell
  • Elevação das porfirinas plasmáticas e nas fezes
    • No urinary porphyrins (because not water soluble)
 
Treatment
  • Fotoproteção
  • β-carotene - reduce production of reactive oxygen specicies
    • 120-180mg/day adults
    • 15-90mg/day in children
    • Carotenemia should be 600-800pg/dL
    • Causes yellowish discoloration of the skin
  • Cholestiramine 4g, 1-4 times/day
  • PUVA and nbUVB to induce melanin production
  • Alfamelanotide → synthetic analog of alphaMSH
  • Should be in darkness in the days before surgery (ex. surgery) where intense light is used