A 35-year-old male presents with a painful, swollen, and red ankle. He reports that he had a fever and rash a week ago, which resolved on their own. On examination, his ankle is warm to touch, and movement is restricted due to pain. What could be the diagnosis, and what should be the next steps?
This patient's history of recent rash and fever followed by an acutely painful, red, swollen ankle joint raises the suspicion of reactive arthritis. Reactive arthritis is an immune response to an infection in another part of the body, often genitourinary or gastrointestinal, and typically manifests within weeks after the infection. The next steps should include lab tests such as ESR, CRP, and potentially HLA-B27. An X-ray may be performed, but it's often normal early in the disease. Treatment generally involves NSAIDs for symptomatic relief.