Proctitis has many causes. It may be a side effect of medical treatments like radiation therapy or antibiotics. Diseases like ulcerative colitis, Crohn's disease, and sexually transmitted diseases may also cause proctitis. Other causes include rectal injury, bacterial infection, allergies, and malfunction of the nerves in the rectum. Symptoms include constipation, a feeling of rectal fullness, left-sided abdominal pain, passage of mucus through the rectum, rectal bleeding, and anorectal pain.
Physicians diagnose proctitis by looking inside the rectum with a proctoscope or a sigmoidoscope.
A tiny piece of tissue from the rectum may be removed and tested for a bacterium, fungus, or virus. Treatment depends on the cause of proctitis. For example, the physician may prescribe antibiotics for proctitis caused by bacterial infection.