Chronic hepatitis C virus infection mimicking rheumatoid arthritis.

We present the case of a young female patient diagnosed two years ago with rheumatoid arthritis (AR) for which she is taking methotrexate (MTX), who develops cutaneous lesions highly suggestive of porphyria cutanea tarda, diagnosis confirmed by biochemical means. It is noteworthy that she was regularly taking oral contraceptives until the moment of appearance of the skin lesions. The association of those two illnesses, particularly in the case of MTX treatment can raise some problems regarding the potential direct causality relationship. This is why we tried a new diagnostic hypothesis: is chronic hepatitis C virus infection, hypothesis that we verified by means of the presence of anti-VHC and of RNA-VHC. It is well known now the association between chronic viral C infection, rheumatoid syndrome and porphyria cutanea tarda (PCT). The latter are extrahepatic manifestations of that viral infection, thus representing a major indication for antiviral treatment. Our patient received that treatment and she had a very good outcome of the skin lesions. We suggest that the differential diagnosis of any arthritis should always comprise chronic hepatitis C viral infection.