PORPHYRIA CUTANEA TARDA
Porphyria cutanea tarda (PCT) is the most common porphyria and is characterized by the development of skin friability and chronic, blistering lesions on the dorsal aspects of the hands and other sun-exposed areas of skin usually in mid or late life. PCT is an iron-related disease resulting from inhibition of hepatic uroporphyrinogen decarboxylase (UROD, the 5th enzyme in the heme biosynthetic pathway). This develops most commonly in adult males in association with acquired susceptibility factors such as excess alcohol use, smoking, chronic hepatitis C or HIV infection and, particularly in females, with estrogen use. Genetic susceptibility factors may include heterozygous UROD mutations (such patients are said to have familial PCT) and HFE (hemochromatosis gene) mutations. PCT responds readily to repeated phlebotomy, low-dose hydroxychloroquine or treatment of hepatitis C (if present). Before treatment is initiated, the disease must be differentiated from other less common porphyrias that cause identical skin lesions but are unresponsive to these treatments. See Table 121-1.
++ Table Graphic Jump Location Table 121-1Porphyria Cutanea Tarda Treatment Table ||Download (.pdf) Table 121-1 Porphyria Cutanea Tarda Treatment Table
|MEDICATION NAME ||INDICATION ||MECHANISM OF ACTION ||DOSING ||ADVERSE EFFECTS ||SUGGESTED MONITORING ||LEVEL OF EVIDENCE (REFERENCE) |
|Procedural Therapy |
|Phlebotomy ||PCTa ||Depletion of hepatic iron ||Removal of 450 mL blood q~2wk until serum ferritin reduced to 15-20 ng/mL ||Anemia || |
Plasma or urine porphyrins
|Systemic Therapy: |
|Hepatitis C direct-acting antiviral therapy ||PCTb ||Treatment of this susceptibility factor ||Follow standard dosing to achieve undetectable HCV mRNA ≥3 months after end of treatment ||Related to individual agents ||Plasma or urine porphyrins ||III2 |
|Hydroxychloroquine ||PCTc ||Mobilizes porphyrins from hepatocytes ||100 mg twice weekly until urine or plasma porphyrins are normal for 1-3 mo ||Transient hepatocellular damage and worsening of photosensitivity, retinopathy, hemolytic anemia ||Ophthalmology exam before treatment and yearly (if needed) Plasma or urine porphyrins ||III3 |
|Desferoxamine ||PCTd ||Iron chelation ||30 mg/kg daily for 1 wk q3mo until serum ferritin reduced to 15-20 ng/mL ||Injection site and allergic reactions, ocular and auditory disturbances, arthralgia, abdominal pain, rare infections, hypotension, blood dyscrasias, neurological disturbance, respiratory distress, impaired renal function, etc. || |
Plasma or urine porphyrins
|Deferasirox ||PCTd ||Iron chelation ||250-500 mg daily until serum ferritin reduced to 15-20 ng/mL ||Renal failure, hepatic abnormalities, GI hemorrhage, cytopenias, abdominal pain, etc. ||Hemoglobin Plasma or urine porphyrins ||III5 |
Levels of evidence are based on the Journal of the American Academy of ...