Colitis in Dogs: A Brief Introduction

By Chelsea Hunt-Rivera / May 21, 2018
Colitis in Dogs

What is Colitis

Colitis refers to a condition of inflammation of the large intestine or colon. You may also hear colitis cited as large bowel diarrhea. The two terms are synonymous.

Colitis is most often used to explain diarrhea or loose stools associated with the large bowel.

Colitis in Dogs colon

Types of Colitis

Three types of colitis may occur: Chronic, Acute, or Episodic. While several symptoms and causes relate to all three types of colitis, there are also clinical signs and underlying causes that are specific to which form of colitis the dog has.

Chronic Colitis

Dogs with chronic colitis have symptoms lasting several months or even years. The symptoms may clear up for weeks at a time and then return but typically get worse as time progresses. With chronic colitis, pet owners typically see more symptoms and clinical signs that their dog has a condition and not just an upset stomach.

Acute Colitis

Unlike chronic colitis, acute colitis comes on suddenly. Often times, dogs with acute colitis do not show any signs of being sick other than diarrhea and straining to defecate. Acute colitis tends to resolve on its own in a matter of a few days which is why the underlying cause often goes without being diagnosed.

Colitis in Dogs

Common Causes of Acute Colitis

Acute colitis is an onset of inflammation that is caused suddenly. Therefore, one of the following irritants is typically at the root of the problem:

  • Stress
  • Ingestion of toxins
  • Ingestion of foreign bodies
  • Eating something they shouldn’t have
  • Dietary change
  • Food intolerance
  • Internal parasites
  • Adverse reaction from a medication
  • Bacterial overgrowth

We’ll discuss these in more detail shortly.

Additionally, acute colitis is frequently found in young cats with intestinal bacterial overgrowth or intestinal parasites.

Episodic Colitis

Episodic colitis is usually sporadic and can last a few weeks with symptoms ranging from mild to severe. The difference between episodic colitis and chronic colitis is the fact that episodic colitis eventually clears up and typically does not cause any lasting effects.

What Causes Colitis in Dogs

While the underlying causes of colitis can vary slightly based on the type of colitis that the dog has, several encompass all three forms.

Stress Diarrhea

It may surprise you to learn that a prevalent cause of colitis in dogs is stress, particularly in shelter dogs. Stress is also a leading cause of colitis in humans.

Stressors such as moving, traveling, and changes in their home can all cause dogs to develop colitis. Stress, depending on the specific stressor, can cause chronic, acute, or episodic colitis, although acute colitis is most common.

Pet owners should aim to determine the cause of stress and whenever possible, eliminate it. A veterinarian may prescribe sedatives to help ease the anxiety issues although generally a good amount of emotional support and care will fix the issue.

Infection | Parasites

Another huge cause of colitis in dogs is a parasitic infestation and infection.Colitis in Dogs worms

Parasites and infections that can wreak havoc on your dog’s gut include:

  • E. coli
  • Salmonella
  • Giardia
  • Whipworms
  • Clostridium
  • Histoplasma
  • Cryptosporidium
  • (Among others)

In order to avoid a potential parasitic infestation, pet owners should closely monitor what their pup is eating and drinking as this is a common way for the infections to spread.

Experts advise pet owners to bring a collapsible bowl on walks to avoid their dog licking puddles of water that may be contaminated.

Your veterinarian will need to examine a stool sample in the case of a potential parasitic infestation in order to treat the root of the problem and ensure that additional issues don’t arise.

Colitis in Dogs dog allergiesAllergies

Food allergies and intolerances to environmental changes can cause colitis in dogs. Also, allergies to medications can cause antibiotic-associated colitis to develop.

Dog allergies may be challenging to diagnose. First, pet owners should evaluate any new changes that have recently been introduced into their dog’s life. Even if no lifestyle changes have been made, we suggest looking into the brand of dog food you’re using to make sure they haven’t added any ingredients without you realizing.

Even the smallest change can cause an adverse reaction such as colitis.


Additionally, colitis in dogs may result from an injury. Ingesting a foreign body, physical trauma, or eating something that they shouldn’t have can all cause inflammation of the entire gastrointestinal tract.

Injury to the IG tract from dietary indiscretion is one of the leading causes of acute colitis in dogs.

Other Diseases That Cause Colitis in Dogs

Colitis is commonly a result of one of the ailments of inflammatory bowel disease (IBD). These disorders include:

  • Lymphocytic plasmacytic enterocolitis
  • Eosinophilic enterocolitis
  • Granulomatous enteritis
  • Neutrophilic enterocolitis
  • Histiocytic ulcerative colitis

Additionally, certain breeds are at a predisposition for developing specific types of inflammatory bowel disease (IBD).

Histiocytic ulcerative colitis is found more often in Boxers than other breeds while German Shepards have more cases of lymphocytic plasmacytic enterocolitis.

Furthermore, many stress-related cases of colitis are being linked to irritable bowel syndrome (IBS) in dogs.

Colitis Symptoms

Symptoms of colitis tend to be the same regardless of whether it is chronic, acute, or episodic.

Frequent, Small Amounts of Diarrhea

The most common symptom of colitis that owners report is constant diarrhea in very small amounts.

Blood in Diarrhea

Watery diarrhea often contains bright red, fresh blood.

Mucus in Dog Stool

In many cases of chronic colitis, mucus or fat is also present in the dog’s stool.

Urgency to Defecate | Straining to Defecate

Many dogs will move with urgency, acting like they need to go to the bathroom right away, and then once outside will strain to defecate.

The constant strain can cause secondary inflammation of the tissues surrounding the anus.

Additionally, the straining to defecate can result in painful cramps and abdominal pain for your poor pup.

Symptoms of Chronic Colitis

There are a few symptoms of chronic colitis that do not appear in acute or episodic colitis.

If your dog has chronic colitis you may notice the following symptoms and changes developing over time:Colitis in Dogs dehydration

  • Dehydration
  • Loss of appetite
  • Weight loss
  • Lack of energy (avoiding play time when they once looked forward to it)
  • Sleeping more than usual
  • Lethargy
  • Poor coat appearance
  • Overall body appearance doesn’t look as healthy as usual (droopy eyes, tail between the legs, etc.)

Pet owners may also see black, tarry stools along with diarrhea containing mucus and bright red blood if the small intestine is also inflamed.

Diagnosing Colitis in Dogs

To provide an accurate diagnosis, your vet will administer the following tests:

  • A CBC (complete blood count)
  • Serum biochemistry profile
  • Urinalysis
  • A physical exam, including abdominal palpation

A stool sample will be necessary in order to ensure there is not a parasitic infestation that needs treatment.

Additionally, an x-ray of the abdominal area may be necessary to rule out tumors or masses in the GI tract, fecal impaction, or any other potential abnormalities.

If these diagnostic tests do not provide the vet with a thorough understanding of the issue, a colonoscopy may be recommended. A colonoscopy will allow the veterinarian to remove tissues for additional testing as well as look for any other irregularities.

Colitis Treatment

Treatment for colitis is based on the underlying cause of the condition, which is why it is so important to receive an accurate diagnosis.

Non-specific treatment generally involves withholding food for 24-48 hours and then slowly reintroducing a bland diet.

Some dogs will do better with a low-fiber diet or a hypoallergenic diet, but all treatment is on a case by case base.

Depending on the cause of the colitis, your vet may prescribe:

  • Antimicrobial drugs
  • Anti-inflammatory medication
  • Immunosuppressive drugs

Furthermore, there are several herbal remedies, homeopathics, nutraceuticals, and varying strains of probiotics that pet owners can use to help reduce inflammation of the gastrointestinal tract.

Colitis in Dogs: A Final Thought

Colitis in Dogs

Determining the underlying cause of your dog’s stomach issues can be challenging, but try not to give up. Dogs are sensitive creatures, and it is very possible that something as simple as a dietary change can get Fido back on the road to recovery.

Make sure to consult with your veterinarian if diarrhea persists or doesn’t resolve quickly. It is perfectly normal for your dog to have an upset stomach from time to time, but frequent bouts of irritation can be a sign that something more serious is going on.

For a dog with colitis, the prognosis is very positive and with proper treatment, it can resolve within days. We know you want what’s best for your furry companion. Whether anti-inflammatory drugs are necessary or you simply need to eliminate a stressor in your dog’s life, a proper diagnosis and specifically formulated treatment plan will ensure that your pup lives their best life possible, without any intestinal inflammation.


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About the author

Chelsea Hunt-Rivera

Chelsea Rivera is a Dedicated Pet Parent who loves to create amazing content for pet owners and is helping change pet wellness as the Head of Content for