Severe ulcerative colitis induced by COVID-19 vaccination.

A 37-year-old woman developed severe colitis with diffuse mucosal erythema and ulcerations throughout the entire colon after the 3rd vaccination of COVID-19. Stool culture was negative, and the pathological findings showed increased lymphoplasmacytic and neutrophilic infiltration in the colonic lamina propria, which were consistent with ulcerative colitis. After the treatment with anti-tumor necrosis factor-α agent, the ulceration markedly improved with development of severe colonic stenosis, which was successfully dilated with endoscopic balloon dilation. In case of COVID-19 vaccination, it should be noted that vaccination could be a trigger for the onset of UC.