Is Colitis in Dogs Hereditary?

Colitis in dogs is the inflammation of the large intestine. This inflammation can be acute or suddenly occurring for a brief time, or it can be chronic or long lasting. Acute colitis responds to therapy within one to three weeks. Chronic colitis can last for years or even a lifetime, with no cure available, but only management of the disease. Diet and medications can make the disease manageable.


Signs can range from subtle to severe, even debilitating or fatal. Medications and dietary therapy can help control the inflammation, but usually does not cure it. The inflammation leads to excessive water in the stool, hence the diarrhea. Mucus and/or blood may also be present. The diarrhea can be continuous or intermittent with all or any one of the following: abdominal pain, fever, depression, weight loss and dull coat.


Though the exact cause of your pet's colitis may or may not be determined, the following is a list of possible causes.

Acute colitis:

Chronic colitis:

  • Ulcerative - Serious chronic inflammation and ulceration of the lining of the colon
  • Prototheca - Caused by algae
  • Histoplasma - Caused by fungal infection
  • Eosinophilic - Caused by food allergies
  • Whipworms
  • Tumors
  • Polyps
  • Allergies
  • Spastic
  • Foreign body
  • Prolonged use of antibiotics

Heredity can play a part, such as in the case of young Boxers, who can develop a chronic, debilitating inflammation of the colon. This type of diarrhea can be accompanied by occasional vomiting, lack of appetite and weight loss.

Some other breeds are susceptible to developing colitis; however, it is not known whether heredity plays a part or if it is a result of food or environmental allergies.

Signs and Symptoms

The following are signs and symptoms of colitis in dogs:

  • Diarrhea
  • Loss of appetite
  • Abdominal pain and tenderness
  • Fatigue
  • Cramping
  • Bloating
  • Urgency to relieve
  • Weight loss
  • Fever
  • Changes in bowel habits
  • Bleeding, seen as black or tarry stools
  • Colon ulcers


Whenever colitis is suspected, the following tests are used to confirm the diagnosis: 

  • White and red blood counts
  • Blood chemistry
  • Abdominal palpation
  • Rectal exam
  • Urinalysis and fecal examinations
  • Bacterial cultures
  • X-rays
  • Colonoscopy
  • Biopsy
  • Exploratory surgery

Results of these tests along with the observations of the signs listed above will confirm the diagnosis of colitis.


There is no cure for colitis, only management of the disease. Diet and drugs can suppress the inflammation and so prevent recurrences. Increasing the amount of fiber eaten and/or feeding a diet unlikely to induce an allergic reaction are the two options available. Providing bulk to the diet by introducing insoluble fibers will help with the transportation of food and water through the intestine. Fiber increases water retention in the intestines, thereby softening the stool. Increased bulk also increases the propulsive intestinal movements that move the stools along.

A trial phase of about three to six weeks will determine which diet is appropriate for the type of colitis present. During this trial time, symptoms may increase in severity as the dog's body is adjusting to the new diet. It is important to stick with the diet, and to not introduce treats or other foods. If the dog is presently on other medications, it's a good idea to inform the veterinarian since it may be these medicines that are triggering the diarrhea.