Merck Manual

Please confirm that you are not located inside the Russian Federation

honeypot link



Parswa Ansari

, MD, Hofstra Northwell-Lenox Hill Hospital, New York

Reviewed/Revised Jan 2023
Topic Resources

Proctitis is inflammation of the lining of the rectum (rectal mucosa).

  • The inflammation has many causes ranging from infection to radiation therapy.

  • Depending on its cause, proctitis can be painless or very painful.

  • A doctor makes the diagnosis after examining the inside of the rectum.

  • Antibiotics can be used to treat proctitis caused by a bacterial infection.

  • Corticosteroids can be applied to the affected area or sometimes taken by mouth to treat proctitis caused by radiation therapy.

The Digestive System

The Digestive System

Causes of Proctitis

Proctitis has several causes.

It may result from Crohn disease Crohn Disease Crohn disease is an inflammatory bowel disease where chronic inflammation typically involves the lower part of the small intestine, the large intestine, or both and may affect any part of the... read more Crohn Disease or ulcerative colitis Ulcerative Colitis Ulcerative colitis is a chronic inflammatory bowel disease in which the large intestine (colon) becomes inflamed and ulcerated (pitted or eroded), leading to flare-ups (bouts or attacks) of... read more . It can also result from a sexually transmitted infection Overview of Sexually Transmitted Infections (STIs) Sexually transmitted infection (STI) refers to an infection that is passed through blood, semen, vaginal fluids, or other body fluids during oral, anal, or genital sex with an infected partner... read more Overview of Sexually Transmitted Infections (STIs) (such as gonorrhea Gonorrhea Gonorrhea is a sexually transmitted infection caused by the bacteria Neisseria gonorrhoeae, which infect the lining of the urethra, cervix, rectum, or throat, or the membranes that cover... read more Gonorrhea , syphilis Syphilis Syphilis is a sexually transmitted infection caused by the bacteria Treponema pallidum. It can occur in three stages of symptoms, separated by periods of apparent good health. Syphilis... read more Syphilis , Chlamydia trachomatis infection Chlamydia and Other Nongonococcal Infections Chlamydial infections include sexually transmitted infections of the urethra, cervix, and rectum that are caused by the bacteria Chlamydia trachomatis. These bacteria can also infect... read more Chlamydia and Other Nongonococcal Infections , herpes simplex virus infection Herpes Simplex Virus (HSV) Infections Herpes simplex virus infection causes recurring episodes of small, painful, fluid-filled blisters on the skin, mouth, lips (cold sores), eyes, or genitals. This very contagious viral infection... read more Herpes Simplex Virus (HSV) Infections , or monkeypox infection Mpox (Monkeypox) Mpox is caused by the monkeypox virus, which is related to the smallpox virus and causes a similar, but usually milder, illness. Mpox is caused by the monkeypox virus, which is related to the... read more Mpox (Monkeypox) ), especially among people who engage in anal-receptive intercourse.

Proctitis may also be caused by some bacteria not transmitted sexually, such as Salmonella, or by the use of an antibiotic that destroys normal intestinal bacteria, thus allowing other bacteria to grow in their place (Clostridioides difficile—see Clostridioides difficile-Induced Colitis Clostridioides (formerly Clostridium) difficile–Induced Colitis Clostridioides difficile (C. difficile)–induced colitis is an inflammation of the large intestine (colon) that results in diarrhea. The inflammation is caused by toxin produced... read more ).

A person whose immune system is impaired is also at increased risk of developing proctitis, particularly from infections by herpes simplex virus or cytomegalovirus.

Another cause of proctitis is radiation therapy directed at or near the rectum, which is commonly used to treat prostate and rectal cancer.

Symptoms of Proctitis

Proctitis typically causes painful straining to defecate, painless bleeding, or the passage of mucus from the rectum.

When proctitis is caused by gonorrhea, herpes simplex virus, monkeypox, or cytomegalovirus, the anus and rectum may be intensely painful.

Diagnosis of Proctitis

  • Proctoscopy or sigmoidoscopy

  • Blood tests and stool tests

  • Sometimes colonoscopy

To make the diagnosis of proctitis, a doctor looks inside the rectum with a proctoscope or sigmoidoscope (a tube used to view the rectum—see Endoscopy Endoscopy Endoscopy is an examination of internal structures using a flexible viewing tube (endoscope). In addition to examinations, doctors can use endoscopy to do biopsies and give treatment. Endoscopes... read more ) and takes swabs and a tissue sample of the rectal lining for examination. The laboratory then can identify the bacterium, fungus, or virus that may be causing the proctitis.

Blood tests for syphilis and stool tests for Clostridioides difficile are also done.

A doctor may also examine other areas of the intestine using colonoscopy (examination of the entire large intestine with an endoscope) to look for Crohn disease or ulcerative colitis.

Treatment of Proctitis

  • Treatment of the cause

Antibiotics are the best treatment for proctitis caused by a specific bacterial infection. Antiviral medications are used for viral infections.

When proctitis is caused by use of an antibiotic that destroys normal intestinal bacteria, a doctor may prescribe fidaxomicin or vancomycin, which should destroy the harmful bacteria that have displaced the normal ones.

Proctitis that is caused by radiation therapy and that is bleeding is treated with corticosteroids applied directly to the lining of the rectum as foam or delivered by enemas. An enema of sucralfate may also help. If these treatments do not help, doctors may directly apply formalin to the lining of the rectum to help stop the bleeding or they may try a treatment that involves the use of oxygen (hyperbaric oxygen therapy Recompression Therapy Recompression therapy involves giving 100% oxygen for several hours in a sealed chamber at high pressures (at least 1.9 atmospheres). (See also Overview of Diving Injuries.) Recompression therapy... read more ).

If proctitis has caused bleeding from the lining of the rectum, doctors can use argon plasma, lasers, electrocoagulation, and heater probes to stop the bleeding.

Drugs Mentioned In This Article

Generic Name Select Brand Names
FIRVANQ, Vancocin, Vancocin Powder, VANCOSOL
quiz link

Test your knowledge

Take a Quiz!