[Arthralgia in psoriasis vulgaris - sometimes it's worth taking a second look]

The 71-year-old patient reported long-standing inflammatory arthralgia due to psoriasis vulgaris. Therapy with methotrexate led to elevated liver values; the symptoms persisted under treatment with the TNFα inhibitor adalimumab.

Using arthrosonography and MRI, a predominantly periarticular inflammatory pattern on the wrists, metacarpophalangeal joints and proximal interphalangeal joints could be objectified without post-inflammatory stigmata of psoriatic arthritis. Laboratory diagnostics revealed an elevated anti-HCV titer with a high viral load consistent with a florid hepatitis C.

A predominantly extrahepatic hepatitis C with associated periarthritis was diagnosed.

With combined, interferon-free antiviral therapy, arthralgia suspended completely.

Hepatitis C can appear through extrahepatic manifestations in the form of periarticular inflammation. Suspicious inflammatory arthralgias in psoriasis vulgaris are not conterminous with the diagnosis of psoriatic arthritis and should be evaluated by a professional rheumatologist.