Porphyria cutanea tarda is the most frequent porphyria and occurs in both sporadic and familial forms. We conducted the current study in a series of 152 consecutive patients with porphyria cutanea tarda attending the Porphyria Unit of the Hospital Clinic of Barcelona, Spain, to update the clinical manifestations of the disease and to study the sex differences, the proportion of familial forms, and the role of different risk factors in this population. Patients were classified as familial and sporadic cases according to erythrocyte uroporphyrinogen-decarboxylase activity and uroporphyrinogen-decarboxylase genotyping.
In our cohort, skin fragility and blisters on the hands were the most frequent clinical manifestations. Women more frequently had facial hypertrichosis (84.8%; p = 0.004), affected areas other than the hands and face (33.3%; p = 0.008), and pruritus (27.3%; p = 0.041) compared with men. Of our patients, 11.8% did not present the typical clinical onset of the disease, with facial hypertrichosis and hyperpigmentation the more frequent complaints in these cases. Analysis of risk factors showed a high prevalence of hepatitis C virus infection (65.8%) and alcohol abuse (59.9%), both being more frequent in men (p < 0.001). Hepatitis C virus infection was the only risk factor that showed differences between the sporadic and familial forms in the logistic regression model (odds ratio, 0.05; 95% confidence interval, 0.006-0.46)
In conclusion, atypical forms of presentation of porphyria cutanea tarda should be considered in order to prevent delayed diagnosis. We note the sustained role of hepatitis C virus infection in the precipitation of sporadic porphyria cutanea tarda. Therefore, in countries with a high prevalence of hepatitis C virus infection, the absence of such infection in a patient with porphyria cutanea tarda may suggest a possible familial case.
Abbreviations: ALT = alanine aminotransferase, F-PCT = familial porphyria cutanea tarda, GGT = gamma-glutamyl transpeptidase, HBV = hepatitis B virus, HCl = hydrogen chloride, HCV = hepatitis C virus, HIV = human immunodeficiency virus, PCT = porphyria cutanea tarda, ROC = receiver operating characteristic, S-PCT = sporadic porphyria cutanea tarda, U/mgHb = coproporphyrinogen formed per hour per mg of hemoglobin, URO-D = uroporphyrinogen decarboxylase.