Ulcerative colitis and diverticulitis are both conditions that affect your digestive system. Although they have some common symptoms, they are entirely different conditions, with unique causes and treatment plans.

A woman lies on a couch clutching her stomach due to pain from a digestive condition like diverticulitis or ulcerative colitis. Share on Pinterest
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Both ulcerative colitis and diverticulitis are digestive conditions that can cause uncomfortable symptoms like stomach pain, diarrhea, and blood in your stool. But there are key differences between the two.

Diverticulitis is a condition characterized by the development of small, bulging sacs in the colon (large intestine). On the other hand, ulcerative colitis is a chronic condition where the inner lining of the colon becomes inflamed and causes ulcers to develop.

Diverticulitis and ulcerative colitis require different treatment plans, which is why it’s important that you visit your healthcare professional if you have symptoms of either condition.

Let’s take a look at the differences and similarities between ulcerative colitis and diverticulitis, as well as how to get a diagnosis and treatment.

While both conditions affect your digestive system and have several overlapping symptoms, ulcerative colitis and diverticulitis are two distinct conditions with unique causes and symptoms. Here’s what to know about each condition.

Ulcerative colitis: Causes and symptoms

Ulcerative colitis is a type of inflammatory bowel disease (IBD). People with ulcerative colitis develop inflammation and ulcers in their large intestine. It’s considered chronic, meaning that people who have the condition have it for life. Still, with the right treatment, many people are able to effectively manage their symptoms.

It’s not known exactly what causes ulcerative colitis. Medical experts believe the following factors may play a role:

  • Your genes: If your parents or grandparents had ulcerative colitis, you may have inherited certain genes that make you more prone to developing it too.
  • Unusual immune reactions: It’s thought that ulcerative colitis may be triggered by abnormal reactions in the immune system.
  • Microbiome differences: Certain bacteria, viruses, and fungi in your digestive tract (known as your microbiome) may play a role in triggering ulcerative colitis.
  • Environmental factors: Experts believe that your surroundings may play a role in causing ulcerative colitis, especially if you have other risk factors.

Ulcerative colitis symptoms can vary a lot from person to person. Some of the most common symptoms include:

  • diarrhea
  • stomach pain
  • blood in stool
  • decreased appetite
  • weight loss
  • fatigue
  • malnutrition, such as anemia
  • decreased growth (in children)

Diverticulitis: Causes and symptoms

Diverticulitis is a condition where small pouches or sacs develop in the lining of your colon (large intestine). These pouches in the wall of your colon can become infected or inflamed, causing a diverticulitis flare-up.

Although there’s no single cause of diverticulitis, it does become more common as you age. There are several other factors that can increase your risk of developing diverticulitis, such as:

  • a family history of diverticulitis
  • a diet that’s low in fiber
  • a diet that’s high in red meat
  • having obesity
  • a sedentary lifestyle
  • smoking
  • decreased immune function
  • certain medications, such as nonsteroidal anti-inflammatory drugs (NSAIDs) and steroids.

Symptoms of diverticulitis are mainly digestive in nature, and may be moderate to more severe. Typical symptoms of diverticulitis include:

Because both ulcerative colitis and diverticulitis have digestive symptoms — and many symptoms that overlap — it’s not possible to tell which condition you have from symptoms alone. That’s why it’s vital to talk with your doctor if you have symptoms of either condition.

The type of physician that diagnoses these conditions is called a gastroenterologist. Many people visit their primary care provider (PCP) first with digestive symptoms, and then get a referral to a gastroenterologist if their PCP thinks a full workup and diagnosis is necessary.

Many of the tests used to help diagnose ulcerative colitis and diverticulitis are the same. Testing may include:

  • blood tests to look for nutritional deficiencies and signs of infections
  • stool tests
  • a colonoscopy, to visualize the lining of the rectum and colon

If your doctor thinks you may have diverticulitis, you may also have imaging tests, such as an MRI, CT scan, or an ultrasound.

If ulcerative colitis is suspected, your doctor may also order a flexible sigmoidoscopy, which is used to view and analyze the lining of the rectum and lower colon. An ulcerative colitis diagnosis often also involves a biopsy of the large intestine.

Ulcerative colitis and diverticulitis have different treatment plans and treatment durations. Again, this is why it’s imperative to get a proper diagnosis so that your treatment plan is geared toward the correct condition.

Treatment for diverticulitis

Typically, treatment for diverticulitis has involved antibiotics to treat infections, along with dietary changes like increased fiber or fiber supplements. However, more recently, experts recommend preserving antibiotics for the most complicated cases of diverticulitis.

Sometimes medications are prescribed to decrease inflammation, and pain relievers are often used to reduce pain and discomfort as the infection clears.

Treatment for ulcerative colitis

Treatment for ulcerative colitis involves a combination of medication and dietary changes, and less commonly, surgery.

Most medications prescribed for ulcerative colitis aim to reduce inflammation in the colon. The type of medicine that’s prescribed will depend on the severity of the disease. Common medications include:

  • Aminosalicylates: Recommended for people with mild to moderate ulcerative colitis, this type of medication (also known as 5-ASA drugs), helps ease symptoms by decreasing inflammation in the colon.
  • Corticosteroids: Used for mild to moderate ulcerative colitis, corticosteroids help decrease your body’s overall immune system response, which reduces inflammation. This medication is usually prescribed for people who don’t get symptom relief from aminosalicylates.
  • Immunosuppressants: Prescribed for people with moderate to severe ulcerative colitis, immunosuppressants decrease your body’s response to its own immune system.
  • Biologics: Developed in a lab from a living organism, these drugs prevent specific proteins in your body from causing inflammation. Biologic drugs are usually used to treat moderate to severe ulcerative colitis.

Surgery is usually only recommended when patients don’t respond to other medical treatments.

Both ulcerative colitis and diverticulitis can be serious, especially if untreated. While most people recover after an acute episode of diverticulitis, ulcerative colitis requires lifelong treatment.

If left untreated, ulcerative colitis can be severe. Complications may lead to:

Treatment of ulcerative colitis is usually effective and long periods of remission are possible. However, having ulcerative colitis may increase your risk of colorectal cancer, especially if the condition is more severe, starts at a younger age, or involves a larger portion of your intestine.

Complications of diverticulitis can include:

  • an abscess in the intestine
  • phlegmon (a reaction where the body tries to contain an infection)
  • a fistula (an unnatural connection between one structure and another, for instance an opening between the bladder and colon)
  • a perforated colon
  • bowel obstruction (a blockage in the colon)
  • secondary bouts of diverticulitis

Although treatment of diverticulitis is usually effective, about 20% to 50% of people will have recurrent symptoms. Diverticulitis is rarely fatal, though some studies have found that the condition slightly increases your chance of colorectal cancer.

Yes, it’s possible to have both ulcerative colitis and diverticulitis at the same time. While there’s not a lot of research about this phenomenon, it’s considered a rare occurrence.

If you have any symptoms of diverticulitis or ulcerative colitis, it’s important to get a proper diagnosis to determine if you have one or the other condition, or both at the same time.

Ulcerative colitis and diverticulitis are both conditions that affect your digestive system. They have some symptoms in common, such as abdominal pain, diarrhea, and blood in the stool. However, they are entirely different conditions, with different diagnoses and treatment plans.

If you have symptoms of either condition, it’s important to see your doctor to determine whether you have either of these conditions. Without the right treatment, both ulcerative colitis and diverticulitis can get worse and lead to potentially serious complications.