Enteritis in Dogs

Causes, Treatment, and Prevention

Dog lying on sofa at home, looking ill and sad
Photographer, Basak Gurbuz Derman / Getty Images

All dogs are at risk of developing enteritis — a condition that results from an inflamed small intestine. Enteritis can be caused by ingesting toxins, viral or bacterial infection, and intestinal blockage. The primary symptoms of enteritis are diarrhea and vomiting, and if left untreated can result in life-threatening dehydration. Your vet will diagnose enteritis based on clinical signs and medical history and treat your dog in accordance with what is causing the illness. The prognosis for dogs that receive treatment is good, and you can take several measures to minimize the likelihood of your dog experiencing enteritis. 

What Is Enteritis?

Enteritis is the inflammation of the small intestine. It often occurs concurrently with stomach and large intestine inflammation. The most common form of enteritis is gastroenteritis, which occurs when the small intestine and stomach are inflamed. 

Symptoms of Enteritis in Dogs

If you notice your dog is experiencing prolonged gastrointestinal distress, visit your vet.

  • Diarrhea
  • Vomiting
  • Loss of appetite
  • Lethargy
  • Weight loss
  • Black, tarry stool
  • Abdominal discomfort
  • Fever

The most common symptom of enteritis is episodes of diarrhea. The diarrhea is often accompanied by vomiting and residual appetite loss, weight loss, and lethargy. If your dog's vomit or stool has a black, tarry appearance, it may signify bleeding in the small intestine, in which case, visit your vet immediately. Sometimes, dogs have diarrhea or vomit acutely without cause for alarm, but if your dog is sick for days, there may be a serious explanation. Acute cases resolve quickly and usually independently, while chronic or untreated enteritis can lead to more severe symptoms.

Causes of Enteritis

Enteritis can occur for a variety of reasons.

  • Toxins: Ingesting toxins, such as cleaning products, poisonous plants, and toxic or spoiled foods can cause enteritis in dogs. Introduction to a new medication can cause a similar reaction.
  • Infection and disease: Bacterial, viral, or parasitic infection may lead to enteritis. Salmonella bacteria commonly cause stomach upset. Intestinal cancer can also cause enteritis symptoms.
  • Intestinal obstruction: If your dog eats something that obstructs or irritates its small intestine, the intestine may become inflamed and result in enteritis.
  • Stress: Extreme fear, stress, or anxiety can cause enteritis in dogs. This usually combines the inflammation of the small intestine and the colon, which is called enterocolitis.

Diagnosing Enteritis in Dogs

If your dog is exhibiting symptoms of enteritis for more than a day, you should visit your vet for a diagnosis. Your vet will begin by discussing your dog's medical history and performing a physical examination and diagnostic tests like fecal analysis, blood analysis, urinalysis, endoscopy, and imagining tests may be performed to determine the cause of the enteritis. The symptoms of enteritis are similar to those of many diseases of wide-ranging severity. A proper diagnosis is essential in giving your dog appropriate treatment. 

Treatment & Prevention

After your vet determines the cause of your dog's enteritis, they will prescribe a treatment plan. Your dog may be prescribed a dewormer, an antibiotic, and supportive care such as fluid replacement and electrolyte rebalancing. Additional medications may include anti-diuretics, antiemetics, and anti-acids. Some cases of enteritis will resolve on their own. However, after a day or two of diarrhea, your dog may be dehydrated and in need of fluid replacement. If left untreated, enteritis can sometimes be fatal in dogs.

You can take several preventative measures against enteritis. Be sure your dog is up to date on all of its recommended vaccinations to prevent illnesses. Administer monthly heart-worm prevention and flea control treatment to help prevent parasitic infections, keep food and trash out of reach from your dog, and keep your dog on a leash to avoid exposure to harmful substances or contaminated water.

Prognosis for Dogs With Enteritis

Most dogs will recover from enteritis in a few days with proper treatment, but severe cases may take longer. Dogs suffering from extreme dehydration from enteritis are at risk of dying, making fluid replacement therapy essential. If untreated, enteritis can turn into acute hemorrhagic diarrhea syndrome (AHDS), a similar but even more damaging condition. 

  • Is enteritis the same as gastroenteritis?

    Enteritis is the inflammation of the small intestine, while gastroenteritis is the inflammation of the small intestine and stomach. The symptoms of the conditions are similar, and include vomiting and diarrhea.

  • Is enteritis fatal?

    Enteritis is easily treated with a high recovery rate. However, if the enteritis goes untreated, your dog could die from dehydration.

  • How long do symptoms need to last before I need to take my dog to the vet?

    If your dog is vomiting or having diarrhea for longer than a day, visit your vet to discuss possible diagnoses and treatment options.