Erythematous mucosa is an inflammation in the lining of the digestive tract. Possible causes include colitis, gastritis, proctitis, and anusitis. Some cases can eventually lead to cancer. Treatment can depend on the cause of erythematous mucosa.

The mucosa is a membrane that lines the digestive tract. Erythema means redness. So, erythematous mucosa refers to redness and inflammation in an area of the digestive tract’s lining. Erythematous mucosa is not a health condition in itself, but a sign of an issue that may need medical attention.

In this article, we explore the health issues that can cause erythematous mucosa and their other signs and symptoms. We also look at the treatment options.

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The underlying condition associated with erythematous mucosa depends on the part of the digestive tract that is red and inflamed. For example:

  • Gastritis is inflammation of the mucosal lining in the stomach.
  • Colitis is inflammation of the mucosal lining in the colon.
  • Proctitis is inflammation of the mucosal lining in the rectum.
  • Anusitis is inflammation of the mucosal lining in the anal canal.


The main cause of gastritis is the bacterium Helicobacter pylori. Other causes may include:

  • other organisms, such as the herpes simplex virus
  • tobacco and alcohol use
  • acid reflux
  • the use of steroids and nonsteroidal anti-inflammatory drugs, or NSAIDs, such as ibuprofen
  • a vitamin B12 deficiency, in the case of autoimmune gastritis

Autoimmune gastritis often appears with an iron deficiency that leads to a B12 deficiency. This type of gastritis is more common among younger adults who are female.


Colitis is common, and its prevalence is growing throughout the world. The causes may include:

  • infections, with bacteria, viruses, or parasites
  • the use of anti-inflammatory drugs, such as ibuprofen, aspirin, beta-blockers, statins, and immunosuppressive drugs
  • the inflammatory bowel diseases (IBDs) Crohn’s disease and ulcerative colitis
  • microscopic colitis, which may result from celiac disease, type 1 diabetes, thyroid dysfunction, or psoriasis
  • ischemic colitis, which results from a low blood supply
  • radiation, especially to treat cancer in the reproductive organs, the urethra, or the rectum

Proctitis and anusitis

Various factors cause proctitis and anusitis, such as:

The symptoms that occur alongside erythematous mucosa depend on the underlying condition causing them.


Many people with gastritis do not experience symptoms. However, some may have:


Symptoms of colitis include:

  • abdominal pain
  • watery diarrhea
  • a fever
  • an urgent need to have bowel movements
  • blood in the stool

Ulcerative colitis involves ulcers forming in the colon. If a person has this, they may experience:

  • inflammation of the clear layer protecting the whites of the eyes
  • red, painful lumps at the front of the legs, below the knees
  • large, painful sores on the legs

Proctitis and anusitis

Some people with proctitis or anusitis have no symptoms. But a person may experience:

  • bloody mucus and pain during a bowel movement, anal sex, or a digital exam
  • constipation
  • a fever
  • diarrhea
  • difficulty controlling urination and bowel movements
  • pelvic pain

If the inflammation results from an STI or IBD, a person may have:

  • abscesses around the anus
  • anal fissures
  • ulcers in the rectum or around the anus
  • bleeding from the rectum

Doctors treat erythematous mucosa by addressing the underlying health condition.


If gastritis results from H. pylori, doctors tend to prescribe antibiotics, such as:

  • amoxicillin (Amoxil)
  • clarithromycin (Biaxin)
  • metronidazole (Flagyl)

For autoimmune gastritis, a doctor may suggest taking iron and vitamin B12 supplements — as well as an antibiotic, if an H. pylori infection is present.

Some strategies for reducing gastritis symptoms include:

  • avoiding alcohol
  • not smoking
  • avoiding anti-inflammatory drugs, such as ibuprofen, if possible
  • limiting the consumption of spicy foods
  • practicing stress management techniques


If this results from a bacterial infection, the doctor may prescribe antibiotics. They are more likely to do so if the person also has an immunosuppressive condition, such as HIV.

To treat ulcerative colitis, a doctor may prescribe a product containing 5-aminosalicylic acid. But these treatments may not be suitable for people with Crohn’s disease, who may instead need a type of medication called a tumor necrosis factor antagonist. Infliximab (Remicade) is one example.

The doctor may also prescribe a short course of corticosteroids. While these medications effectively reduce IBD symptoms, it is important to take them only as long as necessary — they can cause serious side effects.

To reduce the symptoms, stop smoking, if this applies, and avoid medications that can exacerbate the symptoms, such as ibuprofen and aspirin.

Proctitis and anusitis

If either issue results from an STI, treatment will focus on that infection. Avoid having sex with others while waiting for the STI test results and, if necessary, receiving treatment.

If proctitis is causing ulcers, the doctor may prescribe the rectal 5-aminosalicylic acid treatment mesalamine (Apriso). They may also prescribe a topical treatment, such as a gel or cream.

Tips for lessening the symptoms of proctitis and anusitis include avoiding:

  • caffeine
  • fizzy drinks
  • beer
  • garlic
  • spices

Practicing stress management techniques may also reduce the duration of the inflammation.

Some conditions that can cause erythematous mucosa can increase the risk of cancer, in certain circumstances.

If a person has gastritis for a long time, they have chronic gastritis. Some chronic gastritis is atrophic, which means that the stomach mucosa no longer functions as it should.

People with chronic atrophic gastritis eventually have an acid-free stomach. This severe form of the illness is one of the highest risk factors for gastric cancer.

However, if gastritis does not result from an infection with H. pylori, the person has a lower related risk of developing gastric cancer. This is because H. pylori can eventually lead to an acid-free stomach, an issue that limits the body’s ability to absorb vitamins and minerals and operate in the usual way.

Ulcerative colitis is a risk factor for colorectal cancer and other colitis-associated cancers. A person with ulcerative colitis and another IBD, such as Crohn’s disease, is more likely to develop colitis-associated cancer, compared with someone who has a different form of colitis.

A 2012 study that took place over 14 years found that people with IBD had a 60% higher risk of colitis-associated cancer than people without IBD. This risk remained the same throughout the study period, suggesting that people with IBD are more susceptible to cancer.

The outlook for a person with erythematous mucosa depends on the condition that has caused it.


Most people who receive treatment see a reduction in their symptoms, though these can reoccur.

People with gastritis have a risk of complications, including:


Depending on the cause of colitis, the condition may:

  • improve without treatment
  • be recurrent, coming back regularly
  • become long-lasting, or chronic

People with recurring, chronic colitis need to have the issue monitored throughout their lives. This is because the condition can lead to:

Proctitis and anusitis

If either issue results from an infection, the symptoms should go away after the infection is treated. If proctitis or anusitis results from an IBD, the symptoms may reoccur, requiring treatment.

Complications of proctitis and anusitis include:

  • abscesses
  • bleeding that leads to anemia
  • fistulas
  • narrowing of the rectum
  • ulcers

Some people with erythematous mucosa have no symptoms. If a person experiences any symptoms of a health issue that causes this inflammation, they should contact a healthcare provider.

Some symptoms require immediate medical attention. Examples include:

  • stomach cramps or pain
  • severe abdominal pain
  • fatigue, shortness of breath, or becoming lightheaded
  • mucus or pus discharged from the rectum
  • stool that is black or tarry, or contains dark red blood
  • vomiting red blood or what looks like coffee grounds
  • bleeding from the rectum

Erythematous mucosa is inflammation of the mucosal lining of the digestive tract. It can be a sign of gastritis, colitis, proctitis, or anusitis.

Environmental factors or an infection may be causing the underlying issue, and treating this issue will resolve the inflammation. The treatment may involve using medication and adopting certain strategies, such as managing stress.

People with these underlying conditions may have a higher risk of gastric or colitis-associated cancers. Also, gastritis, colitis, proctitis, and anusitis may come back. A doctor may recommend lifelong monitoring.