New onset psoriasis in a patient receiving abatacept for rheumatoid arthritis.

Administration of abatacept is a new treatment modality for rheumatoid arthritis (RA). We describe a patient in whom psoriasiform skin lesions developed 4 months after the initiation of abatacept therapy for longstanding, rheumatoid factor positive RA. Histological findings were consistent with psoriasis. The skin lesions subsided after discontinuation of abatacept and reappeared after re-exposure to the drug, suggesting a causal connection between abatacept and the development of psoriasis.