Proctitis: Complete Guide to Symptoms, Causes, Diagnosis, and Treatment

5 days ago

9 min read

Updated: 2 days ago

Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: September 2026

TL;DR

Proctitis is irritation and swelling of the rectum — the muscular tube at the end of the colon through which stool passes on its way out of the body. It causes rectal pain, bleeding, mucus discharge, diarrhea, and the frequent or continuous feeling that you need to pass stool. There are six main causes: inflammatory bowel disease (about 30% of people with IBD have rectal inflammation), sexually transmitted infections, foodborne infections, antibiotics (C. difficile overgrowth), surgery, and food proteins or eosinophil buildup (mostly in infants). Untreated proctitis can cause anemia, ulcers, and fistulas. Treatment depends entirely on the cause — there is no single fix — so identifying it through blood tests, stool tests, sigmoidoscopy, colonoscopy, or STI testing is the essential first step.

Quick Answer

Proctitis is irritation and swelling of the muscular tube connected to the end of the colon, called the rectum. Stool passes through the rectum on its way out of the body. Symptoms can be temporary or constant and include a frequent or continuous feeling that you need to pass stool, rectal bleeding, passing mucus, rectal pain, pain on the left side of the belly, fullness in the rectum, diarrhea, and pain with bowel movements. It is most common in people with inflammatory bowel disease — about 30% of people with IBD have rectal inflammation — but infections, antibiotics, radiation therapy, surgery, and even infant food proteins can cause it. Because treatment depends on the cause, doctors diagnose with blood tests, stool tests, sigmoidoscopy or colonoscopy, and STI testing before treating. Make an appointment if you have any symptoms of proctitis.

What Is Proctitis?

Proctitis is irritation and swelling of the muscular tube connected to the end of the colon, called the rectum. Stool passes through the rectum on its way out of the body.

Proctitis can cause rectal pain, diarrhea, bleeding, and rectal discharge, as well as the constant feeling that you need to pass stool. Proctitis symptoms can be temporary or constant.

Proctitis is common in people who have inflammatory bowel disease (IBD), such as ulcerative colitis or Crohn's disease. Sexually transmitted infections are another frequent cause. Proctitis also can be a side effect of radiation treatment.

Symptoms

Proctitis symptoms may include a frequent or continuous feeling that you need to pass stool, rectal bleeding, passing of mucus through the rectum, rectal pain, pain on the left side of the belly, a feeling of fullness in the rectum, diarrhea, and pain with bowel movements.

Symptom	What you notice
Constant urge to pass stool	A frequent or continuous feeling that you need to pass stool
Rectal bleeding	Blood passed from the rectum
Mucus discharge	Passing of mucus through the rectum
Rectal pain	Pain in the rectum
Left-sided belly pain	Pain on the left side of the belly
Fullness	A feeling of fullness in the rectum
Diarrhea	Loose or watery stools
Pain with bowel movements	Discomfort during bowel movements

When to See a Doctor

The guidance here is straightforward: make an appointment with a health care professional if you have any symptoms of proctitis. Rectal pain, bleeding, and the constant feeling that you need to pass stool should never be ignored or self-managed indefinitely, because untreated proctitis can lead to complications.

Causes: Six Main Pathways

Several conditions, treatments, and other factors can cause proctitis. The most important point to understand is that the cause determines the treatment — the same symptoms can come from six very different pathways.

Cause	How it triggers proctitis
Inflammatory bowel disease	About 30% of people with IBD have inflammation of the rectum; more common in ulcerative colitis than Crohn's disease
Sexually transmitted infections	Gonorrhea, genital herpes, monkeypox, and chlamydia — particularly in people who engage in anal intercourse
Foodborne infections	Salmonella, shigella, and campylobacter infections associated with foodborne illness
Antibiotics	Kill helpful bacteria in the bowels, allowing harmful C. difficile to grow in the rectum and colon
Surgery	Diversion proctitis after surgeries that divert stool from the rectum to a surgically created opening called a stoma
Food proteins	Food protein-induced proctitis in infants fed cow's milk- or soy-based formula, or breastfed by mothers who eat dairy
White blood cell buildup	Eosinophilic proctitis, when eosinophils build up in the rectal lining — mostly affects children younger than 2

Risk Factors

Two risk factors stand out for proctitis.

The first is sexual activity. Practices that increase the risk of a sexually transmitted infection can increase the risk of proctitis. Your risk of getting an STI can increase if you have multiple sex partners, have anal sex, don't use condoms, or have sex with a partner who has an STI.

The second is radiation therapy for cancer. Radiation therapy directed at the rectum or nearby areas, such as the prostate, can cause rectal inflammation. Radiation proctitis can begin during radiation treatment and last for a few months after treatment, or it can occur years after treatment.

Risk factor	Detail
Sexual activity	Multiple partners, anal sex, not using condoms, or a partner with an STI
Radiation therapy for cancer	Radiation to the rectum or nearby areas such as the prostate; can appear during treatment or years later

Complications

Proctitis that is not treated or that does not respond to treatment may lead to complications.

Complication	How it develops	What you may feel
Anemia	Chronic bleeding from the rectum leaves too few red blood cells to carry oxygen to the tissues	Tiredness, possibly dizziness, shortness of breath, headache, a change in skin color, and irritability
Ulcers	Long-lasting inflammation in the rectum leads to open sores on the inside lining of the rectum	Worsening pain and bleeding
Fistulas	Ulcers extend completely through the intestinal wall, forming irregular connections between parts of the intestine, the intestine and skin, or the intestine and other organs such as the bladder and vagina	Chronic infections, drainage, or pain

Prevention: Reducing STI Risk

Because infections are a frequent cause, prevention guidance centers on reducing the risk of sexually transmitted infections. The surest way to prevent an STI is to abstain from sex, especially anal sex.

If you choose to have sex, you can reduce your risk of an STI by limiting your number of sex partners, using a latex condom during each sexual contact, and not having sex with anyone who has sores or discharge in the genital area.

If you are diagnosed with a sexually transmitted infection, stop having sex until after you have completed treatment. Ask a health care professional when it is safe to have sex again.

How Proctitis Is Diagnosed

Because treatment depends on the cause, the diagnostic workup aims to identify which of the six pathways is behind the inflammation.

Blood tests can test for blood loss or infection.

A stool test collects a stool sample for testing, which may help find out if proctitis is caused by a bacterial infection.

Flexible sigmoidoscopy involves a scope exam of the last portion of the colon, called the sigmoid colon. During this test, a slender, flexible, lighted tube called a sigmoidoscope is used to examine the sigmoid colon as well as the rectum. Small samples of tissue may be collected for laboratory analysis — a biopsy.

Colonoscopy uses a thin, flexible, lighted tube called a colonoscope to view the entire colon. A biopsy may be taken during this test.

Tests for sexually transmitted infections involve collecting a sample of discharge from the rectum or from the urethra, the tube that drains urine from the bladder.

Test	What it looks for
Blood tests	Blood loss or infection
Stool test	Whether proctitis is caused by a bacterial infection
Flexible sigmoidoscopy	Examines the rectum and sigmoid colon, with biopsy as needed
Colonoscopy	Views the entire colon, with biopsy as needed
STI tests	Discharge samples from the rectum or urethra

Treatment: It Depends on the Cause

Treatment for proctitis depends on the cause of the condition.

Proctitis caused by an infection is treated with medicines. For proctitis caused by certain bacterial infections, an antibiotic such as doxycycline may be given. For proctitis caused by viral infections, such as the sexually transmitted herpesvirus, an antiviral medicine such as acyclovir may be prescribed.

Proctitis caused by radiation therapy varies by severity. Mild radiation proctitis may not need treatment. But radiation proctitis also can cause serious pain and bleeding that need treatment:

Treatment	How it helps
Medicines	Given in pill, suppository, or enema form — sucralfate, mesalamine, sulfasalazine, and metronidazole help control inflammation and reduce bleeding
Stool softeners and dilation	Help stool pass easier, decreasing pain
Ablation	Destroys damaged, bleeding tissue to improve symptoms — includes argon plasma coagulation and other therapies

Proctitis caused by inflammatory bowel disease focuses on reducing inflammation in the rectum. A health care professional may prescribe anti-inflammatory medicines, either by mouth or as suppositories or enemas — mesalamine or corticosteroids such as prednisone or budesonide. Inflammation in people with IBD often needs treatment with a medicine that suppresses the immune system, such as azathioprine or infliximab. If medicine does not relieve symptoms, surgery to remove a damaged portion of the digestive tract may be done.

Preparing for Your Appointment

Start by seeing your health care team if you have rectal pain or bleeding, or if you constantly feel the need to pass stool. If your care team suspects proctitis, you may be referred to a doctor who specializes in diseases of the digestive system, called a gastroenterologist.

At the time you make the appointment, be sure to ask if there is anything you need to do in advance, such as restricting your diet. Write down any symptoms you are experiencing, including any that do not seem related to the reason you scheduled the appointment. Write down key personal information, including any major stresses or recent life changes. Make a list of all medicines, vitamins, and supplements you are taking. Consider taking a family member or friend along, and write down questions to ask.

Questions worth asking your health care professional:

Is proctitis causing my symptoms?
What are possible causes for my proctitis?
What kinds of tests do I need?
What are my treatment options?
What are the benefits and risks of each treatment option?
I have other medical conditions — how can I best manage them while also managing proctitis?
Are there any restrictions that I need to follow?
Is there a generic alternative to the medicine you are prescribing?
Are there any brochures or other printed material I can take with me?
What websites do you recommend?
Should I plan for a follow-up visit?

Do not hesitate to ask other questions that come up during the appointment.

Conclusion

Proctitis is irritation and swelling of the rectum that produces rectal pain, bleeding, mucus discharge, diarrhea, and — most characteristically — the frequent or continuous feeling that you need to pass stool. It has six main causes: inflammatory bowel disease (in about 30% of IBD patients), sexually transmitted infections, foodborne infections, antibiotics that allow C. difficile overgrowth, surgery, and food proteins or eosinophil buildup in young children. Radiation therapy is a key risk factor, and untreated proctitis can cause anemia, ulcers, and fistulas. Because treatment targets the cause — antibiotics or antivirals for infection, anti-inflammatory medicines or ablation for radiation proctitis, and immunosuppressants or surgery for IBD-related proctitis — getting properly diagnosed with blood tests, stool tests, scoping exams, and STI testing is the essential first step.

CTA: If you have rectal pain, bleeding, or the constant urge to pass stool, make an appointment with a health care professional — the guidance is clear that any symptom of proctitis warrants evaluation. Explore more Rinnit guides on digestive health to understand how your gut works and what to do when it does not.

Frequently Asked Questions

What is proctitis?

Proctitis is irritation and swelling of the muscular tube connected to the end of the colon, called the rectum. Stool passes through the rectum on its way out of the body. Symptoms can be temporary or constant.

What are the symptoms of proctitis?

Symptoms include a frequent or continuous feeling that you need to pass stool, rectal bleeding, passing of mucus through the rectum, rectal pain, pain on the left side of the belly, a feeling of fullness in the rectum, diarrhea, and pain with bowel movements.

What causes proctitis?

Six main causes: inflammatory bowel disease (about 30% of people with IBD have rectal inflammation, more common in ulcerative colitis than Crohn's disease), sexually transmitted infections such as gonorrhea, genital herpes, monkeypox, and chlamydia, foodborne infections such as salmonella, shigella, and campylobacter, antibiotics that allow C. difficile to grow, surgery that creates a stoma (diversion proctitis), and food proteins or eosinophil buildup (mostly in children under 2).

Can sexually transmitted infections cause proctitis?

Yes — STIs are a frequent cause, particularly in people who engage in anal intercourse. Gonorrhea, genital herpes, monkeypox, and chlamydia can all result in proctitis.

Can antibiotics cause proctitis?

Yes. Sometimes antibiotics used to treat an infection kill helpful bacteria in the bowels, allowing harmful C. difficile bacteria to grow in the rectum and the colon.

What happens if proctitis is not treated?

Untreated or treatment-resistant proctitis can lead to anemia (from chronic bleeding leaving too few red blood cells to carry oxygen), ulcers on the rectal lining, and fistulas — irregular connections formed when ulcers extend through the intestinal wall.

How is proctitis diagnosed?

With blood tests (for blood loss or infection), a stool test (to check for bacterial infection), flexible sigmoidoscopy (examining the rectum and sigmoid colon, with biopsy), colonoscopy (viewing the entire colon, with biopsy), and tests for sexually transmitted infections (samples from the rectum or urethra).

How is proctitis treated?

Treatment depends on the cause. Infection-caused proctitis is treated with antibiotics such as doxycycline or antivirals such as acyclovir. Mild radiation proctitis may not need treatment, but serious cases use medicines (sucralfate, mesalamine, sulfasalazine, metronidazole), stool softeners and dilation, or ablation. IBD-related proctitis is treated with anti-inflammatory medicines (mesalamine, prednisone, budesonide), often immune-suppressing medicines (azathioprine, infliximab), and sometimes surgery.