Causes of Colitis in Dogs

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Colitis, or inflammation of the colon, is the culprit behind roughly half of all instances of chronic canine diarrhea, according to WebMD. By the time food gets to the large intestine, or colon, the rest of the dog's digestive system has extracted most of the nutrients. The colon's task is storing feces, absorbing water and digesting remaining nutrients. If it's not functioning properly, diarrhea results.


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Also known as large bowel diarrhea, colitis occurs in acute or chronic forms. The acute type might last only a few days; it's caused by something such as your dog getting into the garbage or eating something nasty. Chronic colitis might not be curable but is manageable with dietary changes.


While diarrhea is the primary symptom of colitis, it's not just ordinary loose bowel movements. Diarrhea resulting from colitis contains blood or mucus, giving it a thicker consistency than the watery stool typically associated with diarrhea. A dog's bowel movement might start out normally but finish with diarrhea. Dogs with colitis might experience flatulence and the need to quickly get outdoors to relieve themselves. Defecating might be painful. Some dogs throw up. Unlike other gastrointestinal ailments, colitis usually doesn't cause dogs to lose weight.



It's important to worm your dog regularly, as worms can cause colitis. Monthly heartworm medications eradicate most other types of worms. Infestation with giardia, a protozoa, can also cause the condition. Infection with various types of bacteria, including salmonella, can lead to colitis. Food allergies might result in colitis. Nervous, stressed-out dogs are more prone to the disorder. Often, the diagnosis is idiopathic colitis, meaning the cause isn't known.

Histiocytic Ulcerative Colitis


Histiocytic ulcerative colitis is also known as boxer colitis because it often affects the boxer breed. This diseases causes ulceration in the colon's lining. Besides boxers, this relatively rare affliction appears in malamutes, bulldogs, mastiffs and Doberman pinschers. Unlike other forms of colitis, histiocytic ulcerative colitis results in weight loss.


Colitis treatment depends on the cause. Your vet tests a fecal sample to determine the presence of bacteria and parasites. A diagnosis of giardiasis requires medication to rid your dog of the protozoa. Your vet might prescribe antibiotics and anti-inflammatories as part of the treatment. Dogs suffering from chronic colitis usually require lifelong special diets, often available only by prescription. Those diagnosed with histiocytic ulcerative colitis might require lifelong medication and dietary changes.


By Jane Meggitt

VCA Animal Hospitals: Colitis in Dogs
WebMD: Colitis in Dogs -- Symptoms and Treatment
petMD: Colonic Ulcer in Dogs
Hill's Pet Nutrition: Chronic Colitis
Veterinary Partner: Colitis -- an FAQ

About the Author
Jane Meggitt has been a writer for more than 20 years. In addition to reporting for a major newspaper chain, she has been published in "Horse News," "Suburban Classic," "Hoof Beats," "Equine Journal" and other publications. She has a Bachelor of Arts in English from New York University and an Associate of Arts from the American Academy of Dramatics Arts, New York City.

Always check with your veterinarian before changing your pet’s diet, medication, or physical activity routines. This information is not a substitute for a vet’s opinion.