From Viral Recovery to Autoimmunity: A Case Report of Rheumatoid Arthritis Emergence After COVID-19.

A woman in her 50s contracted Coronavirus disease 2019 (COVID-19), initially presenting with mild symptoms, and managed conservatively. However, she developed a persistent low-grade fever and insidious joint pain for 1 month, prompting further evaluation. Chest computed tomography revealed bilateral pulmonary infiltrates, leading to hospitalization for COVID-19-associated pneumonia. Despite a 2-week course of ceftriaxone and azithromycin, her condition remained unchanged. Postadmission testing revealed elevated rheumatoid factor, anti-cyclic citrullinated peptide (CCP) antibodies, and matrix metalloproteinase-3, suggesting an inflammatory or autoimmune process. Given concerns for immune-mediated inflammation, she was treated with high-dose methylprednisolone. With pneumonia improvement, she was discharged on oral prednisolone (PSL) (20 mg/day) with a planned taper. Her joint symptoms resolved, and anti-CCP antibody levels normalized during steroid therapy. However, upon PSL tapering and discontinuation, her joint pain recurred, and anti-CCP antibodies became positive again. A rheumatology consultation confirmed rheumatoid arthritis (RA). This case provides rare longitudinal documentation of dynamic anti-CCP antibody changes that paralleled clinical disease activity, illustrating the progression from postviral reactive arthritis to classifiable RA. It underscores COVID-19's potential to trigger autoimmune dysregulation and highlights the need for long-term follow-up with serial autoantibody monitoring in patients with persistent musculoskeletal symptoms after infection.