Patient:
Male, 47 FINAL DIAGNOSIS: Porphyria cutanea tarda Symptoms: Chills • cough dry • thumb swelling
Medication:
- Clinical Procedure: - Specialty: Metabolic Disorders and Diabetics.
Objective:
Challenging differential diagnosis.
Background:
Porphyria cutanea tarda (PCT) is the most common type of the porphyria. It occurs due to the deficiency of enzyme uroporphyrinogen decarboxylase (UROD), which is the fifth enzyme in the biosynthesis of heme and catalyzes the conversion of uroporphyrinogen to coproporphyrinogen. The risk factors for PCT include hereditary hemochromatosis, hepatitis C infection, ethanol abuse, estrogen use, HIV, smoking, chlorinated polycyclic aromatic hydrocarbons, and hemodialysis.
Case report:
A 47-year-old Hispanic man presented with right thumb swelling, redness, and pain for approximately 1 week. Past medical history included HIV/AIDS, hepatitis C infection, alcohol abuse, heroin abuse, and CMV retinitis. Skin examination revealed blistering and hypo/hyper pigmented lesions over the dorsal aspects of the hands and other sun-exposed areas. Serum porphyrins were discovered to be elevated. The quantitative urine porphyrins revealed elevation of uroporphyrins, heptacarboxyl-porphyrins, hexacarboxy-porphyrins, pentacarboxyl-porphyrins and coproporphyrin. Genetic mutation of UROD was not detected. Due to the classic cutaneous lesions, laboratory findings, and associated risk factors, we were able to confirm our suspicion of the sporadic (type 1) form of PCT.
Conclusions:
A strong correlation has been demonstrated between the sporadic (type 1) form of PCT and hepatitis C virus (HCV) infection in multiple studies. The mechanism through which HCV infection may cause or trigger PCT is unknown. PCT has been described for many years, but still eludes the differential diagnosis in a patient with cutaneous findings. The uniqueness of our case is the possibility that combined risk factors have an effect on PCT.