Inflammation of the Intestines in Dogs



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Diseases of the gastrointestinal tract are among the most common medical problems in dogs. This is partly because they have many origins, including everything from an inappropriate diet to serious infectious pathologies. Common symptoms include vomiting and diarrhea, but the inflammation of the intestines can have very severe repercussions. Dogs can tolerate a high level of pain before showing obvious symptoms. In sufficiently acute cases, the causes of an inflamed bowel can be fatal for the dog.
At AnimalWised, we provide an overview of the causes and treatment of inflammation of the intestines in dogs. While this guide provides the possibilities of why a dog has inflamed intestines, it is vital we go to a veterinarian for differential diagnosis.
Types of intestinal inflammation in dogs
Intestinal inflammation simply refers to inflammation of the various tissues of the intestines. These can be localized to certain parts of the small or large intestine, but they can also encompass the intestines as a whole or spread to other parts of the gastrointestinal tract such as the stomach. For the intestines, the type of inflammation can be categorized by the location:
- Gastroenteritis: if both the stomach and intestine are affected.
- Enteritis: if only the intestine is affected while the gastric mucosa is intact.
- Colitis: if the inflammation is located mainly in the large intestine or, more specifically, in the colon.
There are many similarities between these three types of inflammation, often being caused by the same pathology. They can share symptoms, but it is also important to note variations between then, something we will discuss further in this article.
Another way to categorize types of inflammation of the intestines in dogs is by the type of exudate they produce. This refers to the fluids which are released during the inflammatory process. Regardless of the location in the intestine, they include:
- Fibrinous inflammation: produces fibrin.
- Purulent inflammation: produces pus.
- Hemorrhagic inflammation: produces blood.
- Necrotic inflammation: produces dead tissue.
- Catarrhal inflammation: produces mucus.
Catarrhal enteritis or gastroenteritis is the most common type of inflammation in all animal species. It is characterized by producing a dilation of the intestine and damaging the mucosa, filling the intestine with a mucous fluid that is often mixed with serum or pus. As we will see below, its causes can be incredibly varied.
Below, we look at the various causes of bowel inflammation in dogs, including the various types of intestinal parasites in dogs.
Causes of intestinal inflammation in dogs
Although there are many inflammatory processes which affect the intestines of dogs, some are more common than others. The following are the most common causes of intestinal inflammation in dogs:
- Viral or bacterial infection: the presence of pathogenic microorganisms that attack the integrity of the intestinal mucosa is a very common reason why a dog may suffer from intestinal inflammation. There are many bacteria and viruses with the potential capacity to cause this type of tissue damage. These include those that cause well-known pathologies such as canine parvovirus or salmonellosis .
- Parasitosis: another very common cause of intestinal inflammation is parasitic infestation, especially with nematodes and cestodes. These are parasitic worms that attach, feed and reproduce in the digestive tract of dogs. Protozoa are very small microorganisms that cause diseases such as giardiasis or coccidiosis which can also result in bowel inflammation.
- Allergies and intolerances: food allergies and intolerances result an inflammatory reaction at the digestive level, leading to serious discomfort in the animal. Some foods can be more allergenic than others, but it will depend on the sensitivity of the individual animal. Similarly, some breeds appear to have a greater genetic redisposition to allergies than others. Once the allergen is eliminated, the allergic reaction should cease.
- Poisoning: dogs are very curious animals, with puppies and adolescent dogs being especially mischievous. Since they use their mouths to investigate their environment, it is common for them to ingest something they shouldn't. This can include plants toxic to dogs, cleaning products, industrial chemicals, paint or almost anything they may come across. In addition to intestinal inflammation, they can burn and necrotize the mucosa, resulting in the death of the animal.
- Intestinal obstruction: in addition to toxins, dogs can ingest objects they should not. This can include common objects such as socks, toys or pieces of broken plastic, especially if they chew on something they shouldn't. If these objects get stuck in the gastrointestinal tract, the mucosa around them will start to swell, fluids will accumulate and there is a risk that the tissue will die and become necrotic.
- Anxiety and stress: as with people, dogs that suffer from anxiety disorders or are chronically subjected to high levels of stress may develop recurring gastrointestinal problems. These are characterized primarily by episodes of diarrhea and lack of appetite.
- Pharmacological treatment: some drugs can damage the integrity of the gastric and intestinal mucosa. These include certain anti-inflammatory drugs and antibiotics. For this reason, it is recommended not to prolong treatments with this type of drug for too long. If necessary, gastric protectors may be used to lessen their impact. Never give drugs intended for human use to dogs without veterinary prescription.
- Neoplasms: although they are much less frequent, tumors can develop on almost any part of the intestine. The proliferation of cells which cause neoplasms can damage the mucosa and provide further inflammation, the severity of which will depend on the extent and location of the tumor.
Learn more about the treatment of intestinal tumors in dogs with our related article.

Symptoms of intestinal inflammation in dogs
Intestinal inflammation is characterized by thickening and redness of the mucosa. This alters its structure and is often accompanied by the appearance of various exudates. These can include mucus, serum and pus. These manifestations occur within the digestive tract, so they are not always easy to observe. This complicates diagnosis, but we can look at various symptoms which are secondary to intestinal inflammation. The most common clinical signs include:
- Diarrhea: any intestinal inflammation usually causes the production of overly soft or liquid stools known as diarrhea. This is the most characteristic sign of bowel inflammation and the one that usually first alarms guardians. When the mucosa are inflamed, they cannot absorb fluids as well and the result is watery stools. If parasites are the cause, eggs or worms which look like grains of white rice may appear in the dog's stool.
- Blood in the stool: more serious inflammations destroy the mucous layer that protects the stomach and/or intestine, affecting the underlying blood vessels. The color of the blood in the stool can help with diagnosis, since the darker the color, the more digested it will be. The presence of abundant blood in the stool is a veterinary emergency.
- Mucus in the stool: as we have indicated above, the most common type of inflammation in dogs is catarrhal enteritis. This is characterized by the production of large amounts of mucus. For this reason, it is common to see mucus in the stool of a dog with intestinal inflammation. This mucus can be mixed with pus, so its color varies. It is not usually completely transparent, but rather greenish, yellowish or whitish in color. Discover the specific causes of bloody mucus in a dog's stool with our related article.
- Vomiting: intestinal discomfort caused by enteritis, colitis or gastroenteritis often causes vomiting in dogs. They will usually feel nauseous and gag before vomiting.
- Abdominal pain: although dogs cannot express their pain with words, they do give off some signs that can alert us. For example, if the animal walks hunched over with a contracted abdomen, licks their abdomen excessively, yelps when we touch the abdomen or refuses to be petted there, it is likely they are in pain. Learn more with our article on signs of pain in dogs.
- Apathy and lack of appetite: these are two symptoms that can appear in almost any disease, since an animal that is not well will not want to play, walk or eat normally. Intestinal inflammation is no exception and they should disappear as soon as the animal is treated and begins to feel better.
- Fever: fever is a physiological attempt by the body to defend itself and eliminate the agents that are causing the injury, especially when it comes to bacteria and viruses. Although it is a natural mechanism, fever can be very dangerous if it goes too high. You will need to seek veterinary attention urgently if the dog's temperature exceeds 103.1ºF (39.5ºC).
Diagnosis of intestinal inflammation in dogs
The first thing the veterinarian will do to diagnose the animal's problem is to consult their medical history. They will also collate information about their lifestyle, such as their activity levels, diet, vaccination status and whether a deworming schedule has been implemented. When this occurs, the veterinarian will be able to suspect enteritis since the symptomatology will point to its possibility.
Despite suspecting intestinal inflammation, the veterinarian cannot diagnose the specific cause without the correct diagnostic tests. Coprological analysis of the stool will require looking at the consistency and content which can help guide the diagnosis. Blood tests may also be carried out, but diagnostic imaging tests such as x-rays and ultrasounds will help to best locate the inflammation.
While the imaging tests are minimally invasive, other tests may be required which are more so. This includes rectal endoscopy which may be required to detect the location of a foreign body. If the imaging tests suggest the presence of a tumor, a biopsy may need to be taken to determine if it is cancerous. This may require surgery to reach the tumor in the intestine.
Color of a dog's stool can also help a veterinarian diagnose the cause of an inflamed intestine. Our article on why a dog has yellow poop can help explain further.

Intestinal inflammation in dogs treatment
Once the specific cause of bowel inflammation in dogs has been diagnosed, the veterinarian will administer the corresponding treatment. While the treatment will need to be adjusted to the individual needs of the dog and their clinical status, treatment of intestinal inflammation in dogs will usually involve:
- Adapted diet: the administration of a special soft diet will help to ease digestion while they recover from the underlying cause. Probiotic supplementation for dogs may be useful in helping the gut flora to recover and for the intestines to function again.
- Fluid therapy: in the case of profuse diarrhea, it is also often necessary to keep the dog on fluid therapy for a while to prevent dehydration.
- Drugs: certain inflammations will require specific pharmacological and/or antiparasitic treatment to eliminate the agents causing the damage.
- Surgery: inflammation caused by obstructions or neoplasms may require surgery to remove them. In the case of cancer, radiotherapy or chemotherapy may also be required to treat the disease.
In the case of intestinal inflammation due to allergies, an elimination diet will usually be implemented. This requires the removal of certain food allergens until the allergic reaction stops. This is a trial and error method which can take a long time. Foods formulated to be hypoallergenic may also be used. In more complicated cases, allergy tests can be carried out by taking and analyzing blood samples.
Cases of diarrhea and abdominal pain caused by anxiety or stress should be treated as soon as possible by a professional ethologist. It is very important not to underestimate this type of problem. Although it is of an emotional and not physical origin, stress in dogs greatly reduces the dog's well-being and quality of life.
It is worth remembering that some causes of intestinal inflammation are veterinary emergencies, such as obstructions or poisoning. They need to be treated immediately since delaying treatment can worsen the prognosis. Contact a veterinarian as soon as you observe adverse symptoms.

What is the prognosis for a dog with intestinal inflammation
Since the causes are so varied, the prognosis is completely dependent on the clinical status of the dog. If a dog has preexisting health conditions or is otherwise immunosuppressed, it can weaken the prognosis. Delayed treatment can also do the same. While it will depend on each individual case, the earlier the diagnosis the better the prognosis. This is why we want to stress the importance of going to veterinarian as soon as you observe symptoms.
Fortunately, intestinal inflammation in dogs is relatively common. Many mild cases may even resolve on their own. However, even if we observe symptoms such as mild diarrhea, if they persist for more than 24-48 hours, we should contact a veterinarian since this can help to diagnose a chronic issue which can worsen over time. Causes such as poisoning, intestinal obstructions, certain infections or neoplasia are potentially fatal if not treated in time.
Discover more about how to treat an intestinal blockage in dogs with our related guide.
This article is purely informative. AnimalWised does not have the authority to prescribe any veterinary treatment or create a diagnosis. We invite you to take your pet to the veterinarian if they are suffering from any condition or pain.
If you want to read similar articles to Inflammation of the Intestines in Dogs, we recommend you visit our Intestinal problems category.