Diverticular disease and diverticulitis

Your health expert: Mr Christian Macutkiewicz, Consultant General and Hepato-Pancreatico-Biliary Surgeon
Content editor review by Pippa Coulter September 2023
Next review due September 2026

Diverticular disease and diverticulitis are related conditions that affect your large bowel. They can happen if you have small pouches (called diverticula) in your bowel wall. If you have symptoms such as pain in your tummy, it’s called diverticular disease. Diverticulitis is when your diverticula get inflamed or infected.

About diverticular disease and diverticulitis

Diverticula are small pouches that stick out from your bowel wall. They form if the lining in your bowel wall pushes out, forming a bulge or pouch. Lots of people have diverticula in their bowel without realising it.

You may have just one or two diverticula, or you may have hundreds of them. They may be tiny or they may be over 2cm wide.

You’re more likely to get diverticula as you get older. They’re most common over the age of 50.

There are three different terms to describe how diverticula can affect you.

  • Diverticulosis. This is when you have diverticula but they’re not causing any symptoms. Up to one in 10 people over 45 have diverticulosis. This increases to around eight in 10 people over the age of 85.
  • Diverticular disease. This is when your diverticula cause symptoms such as pain in your tummy. Around one or two in every 10 people with diverticula will develop diverticular disease.
  • Diverticulitis. This is if your diverticula get inflamed (red and swollen) or infected. Around one in 25 people with diverticula will develop diverticulitis at some point during their lifetime.

Causes of diverticular disease and diverticulitis

It’s unclear why some people develop diverticula, or go on to get diverticular disease or diverticulitis. But increasing age and having a diet that’s low in fibre are the main risk factors.

Not getting enough fibre in your diet increases your risk of developing diverticula, and of getting diverticular disease or diverticulitis. Fibre helps your digestive system work smoothly. If you don’t eat much fibre, your poo may be hard and more difficult to pass. This creates more pressure in your bowel, which can cause diverticula to form. People who eat a vegetarian diet or a high-fibre diet may be less likely to develop diverticula or to get diverticular disease.

If you have diverticula, you may also be more likely to develop diverticular disease or diverticulitis if you:

  • eat lots of red meat
  • smoke
  • are very overweight
  • take certain types of medicines, such as non-steroidal anti-inflammatory drugs (NSAIDs) or opioids
  • have a weakened immune system due to illness or medicines that suppress your immune system
  • drink lots of alcohol
  • drink lots of caffeine
  • are not very active

Symptoms of diverticular disease and diverticulitis

Symptoms of diverticular disease

If you have diverticular disease, you may:

  • have pain in your tummy that comes and goes – this may start when you’re eating and get better after you poo or pass wind (fart)
  • feel bloated
  • have constipation or diarrhoea
  • find it hard or sore to pee or need to pee regularly
  • notice blood coming from your back passage

Most people have diverticula on the left side of their bowel. This means if you have diverticular disease, the pain is usually on the left side too. But you can also get pain on your right side, particularly if you are Asian.

If you’re regularly getting these symptoms and they’re not getting any better, contact your GP. You should always see your GP if you have any bleeding from your bottom.

Diverticulitis symptoms

If you have diverticulitis, you usually feel very unwell. You may:

  • have constant, severe pain in your tummy, usually low down
  • have a high temperature (fever)
  • have a sudden change in your bowel habits (how often you need to poo)
  • have a lot of blood or mucus from your back passage
  • feel or be sick
  • lose your appetite
  • have a faster heart rate than normal

If you have any of these symptoms, contact your GP.

Diagnosis of diverticular disease

If you have diverticula without any symptoms (diverticulosis), this may only be spotted when you’re having other tests. This might include colonoscopy for bowel screening.

If you see your GP with symptoms like tummy pain or a change in bowel habits, they will want to assess and examine you. They’ll ask you questions about your symptoms, including the type of symptoms you’re getting, how severe they are and how often. They’ll also want to know about your medical history, diet and bowel movements.

Your doctor may want to feel your tummy to check for any tenderness or lumps. They may also ask to feel inside your back passage to check for any tenderness.

Diverticular disease can be hard to diagnose because its symptoms can be similar to those of other conditions. These include:

  • irritable bowel syndrome (IBS)
  • appendicitis
  • gastroenteritis
  • pelvic inflammatory disease
  • ovarian cyst
  • ectopic pregnancy
  • urinary tract infections
  • bowel cancer

Your GP may refer you for some tests, to help make a diagnosis. These may include the following.

  • Blood and urine test. This can check for signs of inflammation or infection.
  • A CT, MRI or ultrasound scan of your tummy and pelvis. These can check for diverticulitis and any complications.
  • A colonoscopy, CT colonoscopy or flexible sigmoidoscopy. These are tests where your doctor can look directly into your large bowel to see if you have any diverticula. This will also help to rule out other conditions and find where any bleeding is coming from.

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Self-help for diverticular disease

If you have diverticula in your bowel, your doctor may advise you on some lifestyle changes you can make. These may reduce your risk of developing symptoms, or help to ease them if you already have diverticular disease.

Eat more fibre

It can help to increase the amount of fibre in your diet. Getting enough fibre can make it easier to go for a poo, and may reduce any inflammation in your tummy and bowel.

Foods high in fibre include wholegrains, fruits and vegetables. It’s best to gradually increase how much fibre you eat. This can help to prevent bloating and wind. It can take several weeks to feel the benefit from an increase in fibre.

Make sure you’re drinking enough fluids if you’re eating more fibre, because fibre absorbs water. You should drink enough to keep hydrated. For most adults, this is around 1.5 to 2 litres of fluid every day. This is roughly the same as eight to 10 glasses of water.

Foods to avoid

It’s best to try to avoid any foods or drinks that could make you constipated if you have diverticular disease. These may include milk and dairy products, coffee, tea and alcohol.

Your doctor may also advise you to avoid nuts, seeds, fruit skins, corn or popcorn if you have diverticular disease. This is due to concern that these foods could get stuck in your diverticula and cause complications. There’s no evidence that they do any harm though.

Other changes

It may also help to ease your symptoms if you:

  • get regular exercise
  • stop smoking
  • lose weight if you’re overweight

You should take paracetamol if you need to, to help with any pain. But don’t take medicines that may cause constipation, such as painkillers containing opioids.

Treatment of diverticular disease and diverticulitis

You won’t need treatment for diverticulosis (when you have diverticula but no symptoms). If you have symptoms, the treatment will be different depending on whether you have diverticular disease or diverticulitis.

Diverticular disease treatment

You may be able to manage your symptoms at home, following the self-help advice above. Your GP may also prescribe the following medicines.

  • A bulk-forming laxative. Your GP may prescribe this if you can’t manage with a high-fibre diet or have ongoing diarrhoea or constipation. This will make your poo softer and bulkier, and easier to pass.
  • A medicine called an antispasmodic if you have bad tummy cramps. This stops your bowel contracting.

You might need to be admitted to hospital for diverticular disease if you have lots of bleeding from your back passage.

Some people with diverticular disease may have surgery to remove the affected section of bowel. Your doctor may suggest this if you keep getting symptoms of diverticular disease and medicines aren’t helping.

Diverticulitis treatment

If you’re feeling unwell with diverticulitis but don’t need hospital treatment, your GP may prescribe antibiotics to take at home. You’ll usually have a course of antibiotics to take for five days. You might not need antibiotics if you’re feeling well. Your doctor may advise you just to take paracetamol until you feel better, and to come back if your symptoms get worse.

Your doctor may advise sticking to clear liquids or low-fibre foods such as white rice or bread, until your symptoms improve. They will tell you if they advise any change to your diet.

Hospital treatment

You may need to go into hospital for diverticulitis if:

  • you can’t control your pain with paracetamol
  • your symptoms don’t get better after two days of treating them at home
  • you aren’t able to take antibiotics by mouth, if you need them
  • you aren’t able to keep down fluids, or can’t drink enough at home
  • you have a complication such as heavy bleeding from your bottom
  • you have a weakened immune system, or other condition that may affect your recovery

If you’re admitted to hospital, you’ll have antibiotics and fluids through a drip inserted into a vein in your hand or arm. You may be told to eat only certain foods to ‘rest’ your bowels.

Most people with diverticulitis recover within about two weeks of starting treatment. Some people may continue to have some symptoms afterwards. Around a third of people go on to have another episode of diverticulitis. Half of these will get it again within one year, and around nine in 10 within five years.

Surgery for complications

Some people who get diverticulitis develop complications that need to be treated with surgery. These may include the following.

  • A pus-filled lump called an abscess on the outside wall of your bowel. You may need a procedure to drain it.
  • Infected diverticula can sometimes burst and cause an infection in your tummy. This is called peritonitis. You’ll need emergency surgery to drain any pus and wash out the inside of your tummy.
  • If an abscess bursts into one of your organs, such as your bladder, you may get a fistula. This is an opening or passageway into the organ. You may need surgery to correct this.
  • If your diverticula keep getting inflamed, your bowel may get narrower or blocked. You may be able to have surgery to insert a stent and open up the section of bowel. Sometimes you may need surgery to remove the damaged or blocked part of your bowel.

Prevention of diverticular disease

Lots of things may make you more likely to get diverticular disease. You can’t avoid some of these things, such as getting older or having certain other conditions. But making certain changes to your lifestyle may help to reduce your chance of getting diverticular disease. These include the following.

  • Increase the amount of fibre in your diet and drink plenty of fluids.
  • Do regular physical activity.
  • Aim to maintain a healthy weight.
  • If you smoke, try to stop.

Symptoms of diverticular disease include tummy pain, feeling bloated, and constipation or diarrhoea. Some people get bleeding from their back passage. You’ll often feel any pain on the left side of your tummy, but it can happen on the right. For more information, see our symptoms of diverticular disease and diverticulitis section.

It’s probably best not to have any food or drinks that could increase constipation. Your doctor may suggest that you avoid nuts, seeds, fruit skins or popcorn. There’s no evidence that these foods will cause any harm, though. You can find out more in our self-help for diverticular disease section.

Yes, around a third of people who have had diverticulitis will get it again.

This most often happens in the first five years after their first episode. Eating a high-fibre diet will help to keep your diverticular disease under control. If you keep getting diverticulitis, you may need to have surgery. Read more in our treatment of diverticular disease and diverticulitis section.

If you have diverticular disease, it means you have pouches in your bowel wall that are causing symptoms. These include tummy pain. Diverticulitis is when these pouches become infected or inflamed. Symptoms can come on suddenly and can be much more severe. See our about diverticular disease and diverticulitis and symptoms of diverticular disease and diverticulitis sections to find out more.

Symptoms of diverticular disease can often be managed at home with painkillers. If you keep getting symptoms, or if you develop diverticulitis, it can become more serious. You may need hospital treatment if you can’t control your symptoms at home or if you develop complications. See our treatment of diverticular disease and diverticulitis section to read more.

It’s not known exactly what causes someone with diverticula to develop diverticulitis. But there are several things that may increase your risk. These include not getting enough fibre, eating lots of red meat, being obese, and having a weakened immune system. We have more on this in our causes of diverticular disease and diverticulitis section

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