Dass, S., et al. - The B cell-depleting monoclonal antibody rituximab is a novel therapy for the rheumatic diseases, with an increasing body of evidence regarding its safety and efficacy in an expanding range of indications. However, there is uncertainty over its potential use in, and impact on, autoantibody-negative diseases. We describe 3 patients, with no known risk factor for psoriasis, who developed psoriasis (and 1 who also developed features of psoriatic arthritis) after receiving rituximab for a variety of indications, namely, seropositive and seronegative rheumatoid arthritis and systemic lupus erythematosus