Fibroblastic rheumatism (FR) is a rare dermatoarthropathy with a sudden onset. It was first described in 1980. Fewer than 40 cases have been reported, with the majority of those cases occurring in adult white males. The pathogenesis of FR remains unknown, although an infectious trigger has been suggested in some cases. The primary clinical findings of FR include multiple cutaneous nodules, typically involving periarticular areas such as the hands, feet, elbows and knees, and a symmetrical arthropathy of both large and small joints. Other clinical findings can include flexion contractures of the digits, sclerodactyly, Raynaud phenomenon, fever, and a progressive erosive arthropathy.

Diagnosis is suspected based on clinical findings (cutaneous nodules and polyarthritis) and confirmed by biopsy.

• Histopathology remains the key to diagnosis.
• Radiologic testing can be used to look for evidence of joint destruction.
• Laboratory findings often demonstrate an elevation of nonspecific positive acute-phase reactants (inflammatory markers) such as erythrocyte sedimentation rate (ESR) and/or C-reactive protein (CRP). Serum testing for antinuclear antibodies, rheumatoid factor autoantibodies, and other serum antibodies (eg, anti-glomerular basement membrane antibodies, anti-neutrophil cytoplasmic antibodies) is routinely negative in the absence of concomitant rheumatic and non-rheumatic conditions.

The course of FR is variable with the potential for frequent relapses (over months to years) and progression to an erosive arthropathy. The resultant joint destruction can be significant and lead to functional loss and permanent disability. For this reason, early initiation of treatment is recommended in an attempt to modify the destructive course of the disease and prevent incapacitating joint sequelae and deformity.

The treatment for FR is anecdotal and primarily based on data from isolated case reports. Non-steroidal anti-inflammatory drug (NSAID) therapy, systemic corticosteroids, methotrexate (MTX), hydroxychloroquine, interferon-alfa, and colchicine are just some of the medications that have been tried to date. MTX has been used in a number of cases, many of which have had positive clinical responses, including marked improvement or resolution of joint pain and/or skin nodules. Moderate- to high-dose oral corticosteroids have also been used with some success.