A 32‐Year‐Old Man with Skin Lesions

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Diagnosis: Porphyria cutanea tarda (PCT). The diagnosis was based on the photodistributed pattern of blistering, chronic pruritic skin lesions, increased skin fragility, and bruising (figure 1). Serological tests for hepatitis detected antibody to hepatitis C virus (HCV), with an HCV RNA load of copies/mL and an HCV-1b genotype. The patient 6 1.18 10 tested negative for HIV, and results of iron studies were normal. The clearance rate of urinary uroporphyrin was 891 mg/day (normal range, 10-50 mg/day). Urinary uroporphyrin clearance rates of 1800 mg/day have been associated with photosensitivity [1]. PCT is the most common form of porphyria and is commonly found in adults with liver disease and hepatic iron overload (figure 2) [2–4]. In both familial and sporadic forms of this disease, the primary abnormal condition appears to be the reduced activity of uroporphyrinogen decarboxylase. Studies involving large groups of patients with PCT have found a high frequency of HCV infection [5]. The pathogenesis of the skin lesions remains unknown. The differential diagnosis of skin lesions in patients with HCV includes PCT, mixed cryoglobulinemia, lichen planus, leukocytoclastic vasculitis, polyarteritis nodosa, erythema multiforme, and erythema nodosum [6]. Treatment of PCT involves avoidance of precipitating factors, such as alcohol use, sun exposure, and estrogen therapy, together with treatment of HCV infection (if present). Phlebotomy can be attempted, because iron depletion—even in the absence of iron overload—often leads to improvement in both dermatological and hepatic manifestations [7, 8]. Chloroquine therapy has also been used successfully in cases of PCT that are refractory to phlebotomy [9, 10]. There is increasing evidence of the efficacy of IFN-a therapy in patients with chronic HCV infection, and case reports document successful treatment of HCV-associated PCT with INF-a [11, 12]. Our patient was advised to avoid triggering factors—namely, to cease consuming alcohol—and is being evaluated for combination IFN-a– ribavirin therapy for treatment of HCV infection.