Proctitis has many causes, including acute, or sudden and short-term, and chronic, or long-lasting, conditions. Among the causes are the following:
Sexually transmitted diseases (STDs). STDs that can be passed when a person is receiving anal sex are a common cause of proctitis. Common STD infections that can cause proctitis include gonorrhea, chlamydia, syphilis, and herpes. Herpes-induced proctitis may be particularly severe in people who are also infected with the HIV virus.
Non-STD infections. Infections that are not sexually transmitted also can cause proctitis. Salmonella and Shigella are examples of foodborne bacteria that can cause proctitis. Streptococcal proctitis sometimes occurs in children who have strep throat.
Anorectal trauma. Proctitis can be caused by trauma to the anorectal area—which includes the rectum and anus—from anal sex or the insertion of objects or harmful substances into the rectum, including the chemicals in some enemas.
Ulcerative colitis and Crohn’s disease. Two forms of inflammatory bowel disease (IBD)—ulcerative colitis and Crohn’s disease—can cause proctitis. Ulcerative colitis causes irritation and ulcers, also called sores, in the inner lining of the colon—part of the large intestine—and rectum. Crohn’s disease usually causes irritation in the lower small intestine—also called the ileum—or the colon, but it can affect any part of the GI tract.
Radiation therapy. People who have had radiation therapy that targets the pelvic area also may develop proctitis. Examples of those at risk are people with rectal, ovarian, or prostate cancer who have received radiation treatment directed to those areas. Symptoms of radiation proctitis, most commonly rectal bleeding, will typically occur within 6 weeks after beginning radiation therapy or more than 9 months after its completion.
Antibiotics. Use of antibiotics may be associated with proctitis in some people. While meant to kill infection causing bacteria, antibiotics can also kill nonharmful, or commensal, bacteria in the GI tract. The loss of commensal bacteria can then allow other harmful bacteria known as Clostridium difficile to cause an infection in the colon and rectum.