Colitis in Dogs

What is colitis?

Colitis refers to inflammation of the large intestine (colon). Colitis most commonly describes diarrhea or loose stools associated with the large bowel. Large bowel diarrhea is another term for colitis.

What are the clinical signs of colitis?

Most dog owners report seeing frequent, small volumes of semi-formed or liquid feces. Many dogs exhibit straining during and after defecation, and small amounts of bright red blood are often passed near the end of defecation. Mucus or fat is seen in many cases of chronic colitis. Most dogs with colitis exhibit a sense of urgency and need to defecate frequently. Vomiting occurs in less than a third of the cases of colitis. Weight loss is rare.

What causes colitis?

There are several causes of colitis: stress, infections (including Salmonella, Clostridium, and E. coli), parasites (including Giardia, Cryptosporidium, and whipworms), trauma, allergic colitis (often to a dietary protein), and primary inflammatory bowel disease (lymphoplasmacytic, eosinophilic, granulomatous, and histiocytic types). Colitis may also occur after ingesting contaminated food, being in contact with infected dogs, or after chronic exposure to a wet environment. Stress colitis is one of the leading causes of large bowel diarrhea in all dogs.

In all cases, the inflammation in the colon results in reduced water absorption and decreased ability to store feces in the colon, causing the classic symptom of frequent, small amounts of diarrhea, often with mucus or blood.

How is colitis diagnosed?

Colitis is diagnosed based on your pet’s clinical signs and history. Additional testing such as microscopic evaluation of the feces, rectal examination, blood tests and X-rays may be recommended. In chronic or recurring cases, advanced diagnostics may be necessary, such as colonoscopy and colon biopsies, fecal cultures, barium enemas, or ultrasound evaluation of the abdomen. These tests are important to rule out conditions such as colonic tumors or polyps, inflammatory bowel disease, cecal inversion, and ileocecocolic intussusception (a rare condition in which the intestines “telescope” or fold into themselves).

How is colitis treated?

The specific cause of colitis will dictate the appropriate treatment. Non-specific treatment includes fasting for 24 to 48 hours, feeding a low residue or hypoallergenic diet, increasing dietary fiber content, and adding fermentable fiber to the food, such as psyllium, beet pulp, or fructooligosaccharides (FOS). Some dogs with colitis will do better on low-fiber diets. Probiotic (beneficial bacteria) formulations can also be helpful.

Antimicrobial drugs may be appropriate, depending on your dog’s diagnosis. Anti-inflammatory or immunosuppressive drugs may be used in cases of inflammatory bowel disease or allergic colitis. Drugs that modify the colon’s motility may also provide symptomatic relief.

What is the prognosis if my dog has colitis?

For most dogs diagnosed with colitis, the prognosis is excellent for a speedy recovery. Treatment with a simple change in diet and medication to resolve the inflammation or infection in the colon is all that is required for most dogs. Most dogs experiencing stress colitis are back to normal within three to five days.

Chronic, severe, or recurrent cases should have further diagnostic tests to determine the exact cause and proper treatment. For many dogs with chronic colitis, strict dietary control and careful use of medications keep the condition under control.