Hematemesis due to Drug Allergy to Oral Prednisolone in a Patient with Ulcerative Colitis.

The patient was diagnosed with ulcerative colitis and received remission induction therapy with prednisolone. While they developed muscle pain in the lower extremities after starting prednisolone, they ultimately achieved clinical remission. After discharge, hematemesis and gastric discomfort developed. Esophagogastroduodenoscopy showed mucosal edema, redness, and oozing bleeding in the gastric body. In addition, the patient had bloody stool and was considered to have a relapse of ulcerative colitis. They therefore received remission induction therapy with tacrolimus. The patient achieved clinical remission again; however, gastric discomfort and muscle pain remained. A drug lymphocyte stimulation test revealed positivity for prednisolone; therefore, the patient was diagnosed with an allergy to prednisolone.