Colitis in Dogs: Causes, Symptoms, Types & Diagnosis

Coltis Dog Disease

Colitis in dogs is described as inflammation of the colon that can be caused by a number of factors. The causes of this dog health problem include the presence of bacteria, stress, parasites and so on.

Colitis can be an acute condition and may have a sudden onset of short duration. It can also be a chronic condition if it is present for more than 2 to 3 weeks. Ulcerative colitis is the third type of colitis met in quadrupeds, especially in those belonging to the Boxer breed.

Each has a few similar symptoms, but also different ones, as well as treatments and recommended diets. It is difficult to diagnose because most dogs with colitis may look and act normal.


The most common signs include frequent bowel movements, mucus and/or diarrhea with traces of blood. In severe cases, vomiting may occur as well.

Causes of Colon Inflammation in Dogs

There are some common causes of colon inflammation in dogs, as it follows:

  • The presence of intestinal parasites such as worms, whipworms and giardia, which cause irritation and inflammation of the intestine
  • The presence of indigestible fibers in a dog’s stomach, such as grass
  • Salmonella and Campylobacter
  • Inflammatory bowel disease in dogs (IBD) is a common cause of colitis in canines
  • Irritable Bowel Syndrome (IBS), due to stress or neurological origins may cause colitis
  • Pancreatitis, hemorrhagic gastroenteritis or colon cancer may also be some of the common causes

Acute causes include:

  • Overeating
  • A sudden change in diet
  • Eating stale food
  • Bacterial infection
  • Viral infections
  • Stress
  • Food allergy

Chronic causes include:

  • Poor absorption of food
  • Pancreatic disease
  • Bacterial overgrowth
  • Inflammatory bowel disease
  • Vermin

A dog’s healthy body can sometimes react to an infection or an illness by taking refuge in itself. More specifically, in some cases, the products of urine or waste return in a dog’s body instead of leaving it, resulting in abnormal quantities of waste in its blood. Urea, a waste product of urine, is one of the potentially harmful substances that can enter a dog’s bloodstream.

This can also cause other problems in its body. An inflamed intestinal tract can also be a good indicator of inflammation of other organs, not just an indicator of infections. For example, a long-term inflammation of the pancreas can irritate a dog’s bowels.

Polyps and colon tumors often cause the typical symptoms of colitis. The most common malignancies are adenocarcinomas. The presence of tumors at colon level should be considered in those dogs with rectal bleeding.


Polyps can be diagnosed by rectal examination or they can be viewed by the eversion of the rectal mucosa. Usually lobed and dark red, they break easily and bleed profusely. In such cases, there is no way for you to know that your dog is not suffering from colitis, therefore the importance of seeing a vet cannot be emphasized enough not just in this case, but also in general.

Symptoms of Colon Inflammation in Dogs

The colon, also known as the large intestine, is placed above the small intestine in dogs and has 3 basic functions, namely absorbing water, storing wastewater or stool and absorbing nutrients that were not previously absorbed. The large intestine has a higher bacterial density compared to the small intestine, fact which is a cause of health problems in dogs.

Due to parasites and bacteria, a dog’s digestive system can be negatively influenced and stop functioning normally. Some dogs may show only minor symptoms of colitis, while others may be attacked by a more severe version of this disease. Among the most common symptoms of colitis in dogs are:

  • Stools that look like jelly or mucus
  • Frequent stool evacuation in small quantities
  • Traces of blood in stool
  • Diarrhea
  • Stool consistency varies from liquid to solid or is a mixture of both
  • Having a hard time to defecate
  • Flatulence
  • Vomiting
  • Fever
  • Abdominal pain
  • Weight loss

Read our article on how to help your dog lose weight.

Constipation is a clinical sign characterized by absent, infrequent or difficult defecation, associated with fecal impaction in the colon and rectum. This is a symptom that sometimes occurs in colitis. The problem with feces retention in these areas is water loss.

Therefore, if your dog is too dehydrated because of the diarrhea it previously had, it might not even be able to defecate anymore. Intravenous hydration might be mandatory in such case, but this is something that only a veterinarian can recommend and administer. This procedure might not apply to all ill dogs.

3 Types of Colitis in Canines

Colitis in canines can be divided into 2 main categories, namely acute colitis and chronic colitis. Acute colitis occurs suddenly and it is often called the stress-related colitis because it is caused by sudden stressful episodes in the life of a dog.

Other causes of acute colitis can be, for example, eating from the trashcan or eating foods that are not included in a dog’s diet. Chronic colitis lasts for a longer period of time compared to acute colitis.

The causes of chronic colitis are also diversified and they should be accurately determined before starting a treatment of any kind. Acute colitis is often caused by caused by dog eating grass, dirt or a foreign body, like a little toy.

Chronic colitis is much more serious and usually a biopsy is needed in order to find the cause. The causes of chronic colitis include parasites, bacteria or diseases such as inflammatory bowel disease, irritable bowel disease or, rarely, cancer.

Ulcerative colitis, the third main form of colitis in canines, is rare and it usually occurs because of unknown reasons, especially in dogs belonging to Boxer and Bulldog breeds. It is believed that a defect in a dog’s immunity system allows inflammatory cells to invade the walls of the large intestine, inflaming and damaging its coating. The symptoms are the same as for the general colitis, but much more severe.

However, this affection can be treated and kept under control with the help of medication and a strict diet. Chicken, cottage cheese, rice and eggs are often recommended in such cases. Boxer dogs under 2 years old do not have a very optimistic prognosis in care they get ill and the symptoms are severe. They usually lose a lot of weight.

There are many types of inflammatory disorders that can cause colitis or that could be associated with colitis. These disorders are collectively known as inflammatory bowel diseases. This is because their clinical symptoms are very similar.

Even so, identifying the exact disease is mandatory in order to establish a diagnosis and, eventually, a treatment. As it follows, there are a few types of inflammatory bowel diseases explained and a few details about what causes them as well:

  • Plasmacytic lymphocytic colitis is the most common inflammatory bowel disease in dogs. Its final cause is not known, but specialists think it is caused by an overreaction of the dog’s immune system.
  • Histiocytic ulcerative colitis is characterized by ulcers and the inflammation of a dog’s colon. It is most often seen in puppies, especially those from the Boxer breed.
  • Granulomatous colitis is a rare disease that occurs in some dogs. It is similar with the Crohn’s disease met in humans. The term «granulomatous» refers to specific inflammatory cell types that are present in the colon of a dog when this type of colitis develops.
  • Eosinophilic colitis is characterized by eosinophils. That is a type of white blood cell, which is often associated with allergic reactions or parasites. The cause of eosinophilic colitis is not known for sure. The best guesses include allergies and parasites.

Idiopathic chronic colitis is one of the major headaches for veterinarians, as it also affects the small intestine and stomach of a dog. The causes that lead to these processes are not yet fully established, but specialists have incriminated genetic, dietary, bacterial, immunological factors and changes in the permeability of the intestinal mucosa.

Hypersensitive reactions against bacteria, food components or problems with the bowel itself are the first aspects investigated by a veterinarian. Again, the causes can be so varied, that even a specialist may have a hard time establishing the right diagnosis. Besides the 3 main types, the secondary ones are the trickiest.

Diagnosing Colitis in Canine Specimens

The diagnosis is based on clinical signs and the history of your canine pet’s health, as well as on a microscopic evaluation of its stool, a rectal examination, various blood tests and cell tests. Additional examinations might be necessary, such as x-rays, in order to take a look at the dog’s colon and its intestinal tract.

A colon biopsy or a colonoscopy, a stool culture, a barium enema or an ultrasound evaluation of its abdomen may also be necessary in many cases. These tests are important to rule out critical conditions, such as colonic tumors or polyps, the irritable bowel syndrome and another condition when the bowel folds into itself.

Treatment Options for Affected Dogs

If the dog is dehydrated because of chronic diarrhea, as a symptom of colitis, it has to be hospitalized for intravenous rehydration. If the swelling of the colon is sudden and severe, the veterinarian may withhold food from the dog for 24 to 48 hours to allow its colon to relax.

Meanwhile, if the inflammation of the colon is chronic and a scar has formed on the colon, surgical removal may be required. The inflammation determined by a fungal infection may also require surgery. Dog colitis treatment can also include medication, which is prescribed based on the cause that determined it.


If the inflammation of the dog’s colon is the result of whipworms and hookworms infestation, then the vet prescribes drugs meant to remove them. Anti-inflammatory and immunosuppressive drugs may be prescribed if the cause is an autoimmune reaction.

Since some types of colitis are poorly responsive to medical treatment, surgery may be required. This is why any dog owner should consult a veterinarian as soon as he or she notices something wrong about his or her dog. Depending on the severity of the illness, there are also treatments that can be applied at home and that are usually only related to changes in the dog’s diet.

The vet may suggest a high-protein diet that should be prepared at home or pre-packaged and bought from stores. An unfermented fiber supplement, such as bran, can be used to increase the fecal mass, improve muscle contractions in the colon and remove the water from the stool.

Furthermore, some fermentable fibers may be beneficial. Produced by fermentation, fatty acids can help heal the colon and restore its normal bacteria. Some fibers, such as psyllium, can act as laxatives and may not be the best remedy for a disease that causes diarrhea, so it is important to consult a veterinarian before starting any treatment at home.

Milfoil, chamomile and thyme are herbs that reduce the inconvenience caused by this disease and promote healing. The dog should drink about a cup of tea made with 2 teaspoons of chamomile flowers. Not only its digestion will be easier, but the inflammation from its colon will begin to heal, due to this plant’s antiseptic and healing properties.

In case of milfoil flowers, one might not succeed to make his or her dog drink it because it does not have a pleasant taste, but it is also great for healing colitis. As for thyme, it is also a good intestinal antiseptic, a good diuretic and a sedative. The tea made with it should be administered 3 times per day.

Rice plays an important nutritional role in the treatment of colitis. In case of ulcerative colitis, it can be combined with the juice obtained from raw cabbage and carrots. However, there are dog foods especially made for those with colitis or those that suffer from irritable bowel syndrome.

The main idea is for the food to be hypoallergenic and to contain a low amount of fats. Of course, cooking at home is ideal, but if for any reason you cannot do so, then you should buy appropriate food for your pooch. Here are some examples of dog food suited for such situations:

  • The Honest Kitchens Zeal – dehydrated
  • Grandma Lucy’s Pureformance Rabbit
  • Addiction Dehydrated Foods, any kind as long as it contains low fats

Therefore, it can be said that the treatment for this disease, if it is associated with dietary hypersensitivity, is based on the controlled supply of a well-defined diet, free of additives and highly digestible, containing a single protein source that is not present in regular dog food.

The household diets consisting of turkey, duck, lamb, rabbit, deer, sturgeon, or tofu are more suitable, but they can be changed with a commercial hypoallergenic diet that is balanced and suitable for long-term use. Besides the options presented above, you can search for other products that you may find compatible with your dog’s condition and nutritional needs.

The prognosis for Dogs With Colon Inflammations

Dogs With Colon Inflammations

The prognosis is excellent for most dogs that were diagnosed with a type of colitis. Vets expect quick recovery, especially in case dogs were only affected by a mild form of colitis, the acute kind.

As said, stress is among the main causes of acute colitis in canines, so a simple change in their diet and the administration of medication can solve the inflammation issue and dogs can return to their normal life in 3 to 5 days.

Recurrent, severe or chronic cases of colitis require diagnose tests in order to identify the exact cause of their occurrence and establish a proper treatment. In case of many canines that suffer from chronic colitis, their affection is held under control with a balanced diet and medication.


Dogs are like children, when you least expect it, they get sick and you must take care of them. Like humans, dogs can also suffer episodes of colitis. The causes are varied, starting from overeating and going all the way to infections or digestive malformations.

Especially if your dog is still young, you should not overlook this disorder. Even if acute colitis should disappear in approximately 3 days, diagnosing it would be best so you can prevent its reoccurrence in the future.

However, sometimes colitis is only a symptom of a more serious illness. Therefore, taking your pooch to the vet for a proper diagnose is the best thing you can do.

Colitis is a general term used to describe a variety of digestive distress that originates in the large intestine. It may be acute or chronic and develop into ulcerative colitis, although this is a rare form. To prevent the reoccurrence of colon inflammation, avoid exposing your dog to other dogs, contaminated food and humid environments.

Also avoid sudden changes in your pooch’s diet. Hypoallergenic diets are very nutritional and usually recommended for dogs affected by any form of colitis. The repeated recurrences of colon swelling can be expected when they are related to autoimmune diseases, although that is not always the case.