Colitis in Dogs

Colitis is an inflammation of the colon, or large intestine. It may be acute, with sudden onset and short duration, or chronic, that is present for at least two to three weeks or exhibiting a pattern of episodic recurrence.

There are many potential causes of colitis. These include:

Specific inflammatory disorders of the colon. Lymphocytic-plasmacytic, histiocytic, granulomatous, suppurative, and eosinophilic are terms that describe colitis on the basis of the predominant type of cell present in the inflamed colon.

Infectious agents, such as bacteria, viruses, fungi, or parasites

Dietary intolerance or allergy

Dietary indiscretion

Cancer of the colon

Trauma, internal or external

Intussusception, which is a mechanical problem characterized by telescoping of the bowel into itself.

Hemorrhagic Gastroenteritis (HGE), which is an inflammatory disorder of the intestinal tract characterized by hemorrhage and production of a "raspberry jam" appearance to the stool

Pancreatitis (inflammation of the pancreas)

Antibiotic-associated colitis

There is no age or gender association with colitis. One exception is histiocytic ulcerative colitis, which most often affects young boxer dogs.

Most often, colitis causes some combination of fresh bright red blood in the stool, mucus in the stool, straining to defecate, and increased frequency of defecation, often many times per day. With acute colitis, the dog usually does not show signs of systemic illness, but dogs with chronic colitis can experience clinically important weight loss.

What To Watch For 

An occasional bout of acute colitis is not uncommon in the small animal patient. However, it is important to watch for frequent recurrence or worsening of signs, especially if they include systemic signs of illness. Although occasional vomiting occurs in otherwise healthy dogs, repeated vomiting, poor appetite, weight loss and general lethargy should be reported promptly to your veterinarian.