Signs of a Diverticulitis Flare-Up and How to Manage It

Diverticular disease includes diverticulitis and diverticulosis. Diverticulitis is a common condition.

Diverticulosis can occur when the walls of the colon (large intestine) develop weak spots. The weakened areas protrude like little pouches and are called diverticula. People over the age of 50 are more likely to have these outpouchings.

Diverticula may not cause any problems, and most people won’t know they have them unless they have a colonoscopy. But in some people, the diverticula can become inflamed and lead to symptoms such as pain, nausea, and fever. This is called diverticulitis.

This article will describe what might cause a diverticulitis flare-up, the signs and symptoms, and how it might be treated.

Woman feeling lower left abdominal pain as with a diverticulitis flare-up

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Diverticulitis Causes

The reasons why diverticula may become inflamed are not well understood. It’s thought, however, that there could be several things that may cause it:

  • Genetics: Some genes may make diverticulitis more likely. The genes that are already known to be associated with some connective tissue disorders might also be involved in a higher likelihood of having diverticulitis. This is still being studied so it’s still not well understood.
  • Dietary: Diet may help lower the risk of diverticulitis. Eating more fiber as well as having a diet that consists mostly of fruits, vegetables, whole grains, legumes, poultry, and fish were both shown to decrease the risk.
  • Environmental factors: Higher body weight, including weight gain that started in the early adult years, may be associated with a higher risk of diverticulitis. People who smoke didn’t have a greater risk of diverticulitis but do have more complications from a diverticulitis flare-up.

Signs of a Diverticulitis Flare-Up

Diverticula probably won’t cause any symptoms. In some cases, however, diverticula will get inflamed and cause problems, which is called diverticulitis.

Some of the signs and symptoms of a diverticulitis flare-up are:

  • Abdominal pain on the lower left side (sometimes on the lower right side) which feels achy or crampy
  • Abdominal tenderness
  • Bleeding from the rectum
  • Constipation
  • Diarrhea
  • Fever
  • Nausea
  • Pain or burning during urination (sometimes)
  • Vomiting

Risk of Flare-up

For people who have diverticular disease, an acute flare-up of diverticulitis is uncommon. It’s currently thought that the risk is under 5%. People who develop diverticula at a younger age may have a higher risk than older people. Having one episode of diverticulitis makes having others in the future more likely.

Diverticulitis Treatment

Diverticulitis that isn’t complicated by any other conditions might be treated at home. For very mild symptoms of pain, diarrhea, or nausea, a clear liquid diet might be tried first. This should only be done on the advice of a healthcare provider because a liquid diet doesn’t provide enough calories and nutrients for most people on a long-term basis.

When symptoms are more advanced and include things like bladder problems and fever, patients might still be able to receive treatment at home. To start, this would include a clear liquid diet and antibiotics for seven to 10 days. The antibiotics used might include amoxicillin plus clavulanic acid, Bactrim (sulfamethoxazole-trimethoprim), or a quinolone with Flagyl metronidazole.

Treatment in the hospital might be needed for people who can’t manage their treatment at home, such as people who are older have low white blood cell counts, are immunocompromised (have an immune system that’s depressed), have a high fever, or who have other serious conditions.

If diverticulitis becomes complicated, it will need to be treated in the hospital. Some of the complications that might mean hospitalization is needed include:

  • Abscess: A pocket of pus that forms in the body
  • Perforation with peritonitis: A hole in the wall of the intestine which has led to the contents of the intestine (stool) leaking into the abdomen
  • Fistula: An abnormal tunnel or channel between two organs or an organ and the skin
  • Intestinal obstruction: A blockage in the intestine that prevents stool from moving through
  • Stricture: A narrowed part in the intestine

It’s possible that complicated diverticulitis may need to be treated with surgery. One surgery that might be used includes a bowel resection, where a portion of the intestine is removed, and the two healthy ends are joined back together again. 

A second type of surgery is a colostomy. A portion of the large intestine is brought outside the abdomen, which is called a stoma. Stool leaves the body through the stoma and is collected in an appliance that’s worn on the abdomen. A colostomy might be reversed or it could be permanent, depending on many different factors. 

Preventing Flare-Ups

It may or may not be possible to prevent diverticulitis. There is no good agreement among specialists about whether some changes to diet or lifestyle may help prevent diverticulitis

It used to be recommended that people with diverticular disease avoid fiber or foods like corn or seeds. However, it is currently thought that a diet higher in fiber can help prevent diverticular disease.

There has been some study on regular exercise and its relationship to diverticular disease. There’s no agreement on whether or not exercise can help prevent a flare-up. However, a healthy lifestyle that includes exercise is recommended.

Smoking may be associated with worse outcomes from diverticular disease. Quitting smoking may be recommended.

In general, the recommendations to avoid complications will be to live as healthy of a lifestyle as possible. Talk to a healthcare provider about what kind of a diet to follow, which type of exercise to do, and how much.

When to See a Healthcare Provider

People who know they have diverticula may want to be on the lookout for the symptoms of diverticulitis. Pain in the abdomen might be the first sign. It could be constant or it might come and go.

Bleeding from the rectum or blood in the stool is always a reason to see a healthcare provider. It may be a sign of diverticulitis but it could also be a sign of more serious reasons, so it’s important to get it looked at.

Severe abdominal pain, not being able to keep food down, and diarrhea for three or more days are also reasons to seek care from a healthcare provider.


Diverticular disease is common and doesn’t usually cause any symptoms. When diverticula become inflamed, however, they can cause symptoms such as abdominal pain, fever, or diarrhea. It’s important to see a physician to get diagnosed and treated to avoid complications.

A Word From Verywell

Many people have diverticula and don’t know it or don’t know until they have a colonoscopy to screen for colon cancer (which is recommended by the age of 45 years or earlier). They usually don’t cause any problems or symptoms.

When there are symptoms of abdominal pain or other signs, seeing a healthcare provider right away is key. People should check with their healthcare team to find out how to manage diverticulitis when it does happen and to try to prevent it from happening in the future.

Frequently Asked Questions

  • How long does a diverticulitis flare-up typically last?

    After starting treatment, most people should start to feel better in two or three days. If symptoms don’t start to get better by then, it’s time to call a healthcare provider and get instructions on what to do next.

  • Will a diverticulitis flare-up go away on its own?

    A flare-up might go away with conservative home treatment with a liquid diet. However, it’s still important to see a healthcare provider even for mild symptoms to make sure that it is diverticulitis and not something else that might need different treatment.

  • What foods should you avoid during a diverticulitis flare-up?

    A clear liquid diet might be recommended during a flare-up. When the symptoms start to get better, the diet might be advanced to a full liquid diet and then some soft foods. It’s important to get clear instructions from a healthcare provider on how to eat during a flare-up. 

11 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading

By Amber J. Tresca
Amber J. Tresca is a freelance writer and speaker who covers digestive conditions, including IBD. She was diagnosed with ulcerative colitis at age 16.