Occurrence of adult-onset Still's disease after coronavirus disease 2019 BNT162B2 vaccination in a patient with ulcerative colitis: A case report and review of literature.

Key Clinical Message: We report an extremely rare occurrence of adult-onset Still's disease (AOSD) in a patient with ulcerative colitis. The possibility of autoinflammatory conditions such as AOSD should be considered when evaluating or treating symptoms suspected as side effects of the severe acute respiratory syndrome coronavirus 2 vaccination, regardless of the associated comorbidities.

Summary: A woman in her 50s with a history of stable ulcerative colitis (UC) for 20 years, managed using salazosulfapyridine, presented with migratory rashes, spiking fever, edema, and joint pain that started 1 week after receiving the BNT162B2 mRNA vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).