Even mild monarticular or oligoarticular joint symptoms should arouse suspicion in patients taking immunosuppressive therapy (eg, corticosteroids, tumor necrosis factor or interleukin 6 inhibitors) with risk factors (eg, rheumatoid arthritis), a prosthetic joint, or an extra-articular infection capable of spreading to a joint (eg, genital gonococcal infection, pneumonia, bacteremia, any anaerobic infection).