A 34-year-old male who engages in anal receptive intercourse presents to the clinic with a 2-week history of rectal pain, bright red bleeding, tenesmus, and persistent diarrhea. He has family history of Crohn’s disease. Urgent colonoscopy reveals normal ileum and colon but moderate proctitis with patchy ulcerations and copious amounts of mucus. Rectal cultures and biopsy results are pending. The most appropriate next step in management is