Colitis in dogs is an inflammation of the colon, which is the large bowel or large intestine, where ingested food turns into poop. Your dog’s colon is where digested food moves from the small intestine where most of the nutrients are absorbed through the colon and toward the rectum. The colon also helps maintain a balance of fluids and electrolytes in the body and supports microorganisms important for digestion.
When your dog’s colon becomes inflamed, the normal contractions that mix and knead digested material slow down. Instead, the inflammation stimulates what’s known as “giant migrating contractions” (GMCs). Normally, GMCs only occur a few times a day. However, when colitis occurs, GMCs happen more frequently, producing more cramping, increased urgency to poop, and diarrhea. What should you do if you suspect that your dog has colitis?
Symptoms of Colitis in Dogs
If you think that your dog has colitis, dog diarrhea is the most common and obvious sign. However, not all diarrhea is the result of colitis. Diarrhea or loose stool due to colitis often contains mucus and bright red blood, as opposed to tarry, black stool. Colitis causes the dog to poop urgently and often (but in small amounts). At first, loose stool or diarrhea may occur occasionally, but it might become more common with time. Your dog may experience pain or cramping along with diarrhea. In rare cases, a dog may lose weight or even vomit due to colitis.
Dealing with your dog’s diarrhea isn’t just unpleasant for you. In fact, chronic diarrhea as a result of colitis can cause problems for your dog. In addition to pain and cramps, your dog may become dehydrated, and in severe cases, malnourished. They may also become incontinent, meaning they can’t hold in their diarrhea.
Types of Colitis in Dogs
Causes of Acute Colitis in Dogs
Acute colitis occurs when severe symptoms appear suddenly and don’t last very long. This type of colitis in dogs is fairly common. This variant of colitis can occur when you switch your dog’s diet, or in response to certain foods the dog cannot digest properly. Your dog may have gotten an infection from being around sick dogs. They may have accidentally spoiled food, which can cause infection. It can also occur when your dog is stressed, sometimes called stress colitis. In most cases, acute colitis will go away on its own. But how do you treat its symptoms, like intense diarrhea?
First, you should always talk to your vet if your dog is having consistent diarrhea and follow their instructions. Your vet may recommend feeding your dog bland foods like white rice, pumpkin supplements, or yogurt, or adding probiotics for canines to their diet. They may also recommend dog foods designed for sensitive stomachs. The vet may recommend over-the-counter (OTC) diarrhea medications for dogs or prescription dog diarrhea medications.
If diarrhea is severe, your dog could become dehydrated. If you suspect your dog is dehydrated, call your vet right away.
Causes of Chronic Colitis in Dogs
Chronic colitis is defined as having an inflamed colon for two weeks or more. The cause is harder to pinpoint, and treatment can be difficult. Causes of chronic colitis in dogs could be internal parasites, bacterial or fungal infections, food hypersensitivity, eating foreign materials, or even cancer. It could be a type of primary inflammatory bowel disease.
Chronic colitis can be categorized according to the most common type of inflammatory cells in the colon. The types of chronic colitis are:
- Lymphocytic-plasmacytic colitis is the most common type of colitis in dogs. Researchers aren’t sure of the exact cause, but if a dog’s immune system responds abnormally for some reason, inflammatory cells may then disturb the stomach lining.
- Eosinophilic colitis is uncommon. More common in younger dogs, it’s caused by an increased amount of eosinophils (a particular type of white blood cell).
- Granulomatous colitis (also known as histiocytic ulcerative colitis, or HUC) is rare. A piece of the dog’s bowel will often thicken, causing bowel obstruction. This type of colitis can be common in Boxers, and to a lesser extent, in French Bulldogs, Mastiffs, Alaskan Malamutes, and Doberman Pinschers. Recent research suggests that the cause of granulomatous colitis may be an infection of E. coli bacteria.
Diagnosis of Chronic Colitis in Dogs
Finding the cause of chronic colitis may take several steps. First, your veterinarian will want to rule out possible causes like parasites (such as worms, giardia, or coccidia), bacteria, viruses, fungi, or fungi-like organisms. In particular, whipworms can cause diarrhea that looks similar to diarrhea experienced by dogs with colitis.
Your vet will likely examine stool samples for signs of parasites and take bacterial cultures. Even if nothing is found, your veterinarian may decide to prescribe deworming medications, since not all parasites shed eggs that are easy to spot in stool samples. For that reason, they may perform multiple parasite tests and perform a rectal exam (to check for conditions or growths that could cause symptoms similar to colitis).
If the dog still doesn’t improve after deworming, your vet may recommend a feeding trial. During a feeding trial, a dog is fed a restricted diet with as few ingredients as possible (ones that the dog has not previously eaten), then the vet observes them for signs of improvement. They may order bloodwork or urinalysis to exclude other diseases, order radiographs or ultrasounds to examine your dog’s inner organs, or conduct a colonoscopy to look at the inner surfaces of the colon.
Sometimes, even after extensive research, a vet might not be able to determine a cause for colitis in dogs. However, even these colitis cases can often be treated successfully.
How to Treat Chronic Colitis in Dogs
Your vet will address and treat any abnormalities spotted in the tests they conduct. They may also recommend treatments to help with the symptoms, such as pain or diarrhea.
In some cases, your vet may recommend adding a particular type of fiber (psyllium hydrophilic mucilloid, which supports colon health) to your dog’s diet. For dogs with food sensitivities that may upset the colon, your vet may also suggest novel protein diets (containing a protein source the dog has not previously eaten) or hydrolyzed protein diets (containing proteins that have been broken down so they won’t cause the immune system to react). Your vet may recommend a diet containing fructooligosaccharides (FOSs), a prebiotic that reduces intestinal inflammation.
Your vet may also recommend prescription medication, depending on if your dog has an underlying condition. If a bacterial infection is contributing to your dog’s colitis, the vet may prescribe particular antibiotics. If your dog is experiencing severe cramping that causes them pain, your vet may prescribe antispasmodic agents to calm the colon. If stress brings on diarrhea, your vet may recommend prescription anxiety medication.
Your vet may try several different treatments (or combinations of medications) until finding the right one for your dog. If necessary, they may also refer you to a veterinary internal medicine specialist.
