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.

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). Laboratory tests revealed extremely high serum ferritin levels. The patient was diagnosed with adult-onset Still's disease (AOSD) based on the relevant classification criteria after ruling out other diseases. Detection of high levels of interleukin-18, an inflammatory cytokine related to AOSD, supported the diagnosis. Nonsteroidal anti-inflammatory drug monotherapy alone resulted in significant improvements in both the abovementioned symptoms and the elevated inflammatory marker levels. AOSD in a patient with UC is extremely rare. Only one case of AOSD with UC was reported before the coronavirus disease 2019 era. This case indicates that SARS-CoV-2 vaccination can trigger a hyperinflammatory response, classified as AOSD, in a patient with UC, which is extremely rare.