If you notice your dog vomiting excessively, it may have gastritis due to an inflamed stomach lining. Sometimes gastritis is acute, meaning it has an abrupt and recent onset, such as might be triggered by ingestion of toxic matter. Other times, gastritis is chronic, suggesting a more severe underlying cause. Symptoms include blood in vomit, abnormal stool, and decreased appetite. Your vet will perform a series of tests to diagnose gastritis, whether acute or chronic, and treat the condition accordingly. The prognosis depends on what is causing gastritis. 

What is Gastritis?

Gastritis is the inflammation of the stomach and its lining, usually characterized by episodes of vomiting and/or inappetance. When functioning normally, the stomach's mucosal lining protects against acidity, detergents, bacteria, and changes in temperature and repairs damaged tissue.

Gastritis can be acute, with a sudden onset of symptoms attributable to a specific cause, or chronic, where symptoms are persistent and require more comprehensive diagnostics. When the lining is inflamed, it cannot protect a dog's stomach from harmful, foreign matter, leading to a distressed gastrointestinal response. Irritation to the gastric lining can result in more damage from stomach acid and lead to vomiting. If untreated, gastritis can lead to ulcers and infection.

Symptoms of Gastritis in Dogs

The symptoms of gastritis are usually identifiable and incredibly uncomfortable for a dog. The clearest sign of gastritis is intense vomiting. If you suspect your dog has gastritis, visit the vet right away.

Vomiting

The primary symptom of gastritis is vomiting. The vomiting can range in severity and frequency. Vomiting caused by gastritis may look different from a mild case of stomach upset. Vomit from gastritis may be black, bloody, contain bile, or be frothy. If your dog's gastritis results from eating something irritating, the food or foreign matter may also appear in the vomit. Many dogs experience nausea, which may appear as excessive drooling or tooth-grinding.

Abnormal Stool

Gastritis may cause your dog to pass blood in its stool, which will likely be in the form of diarrhea. The stool may also appear black and tarry. If you notice blood in your dog's stool, visit your vet immediately, as it may also be a sign of hemorrhagic diarrhea syndrome.

Decreased Appetite

Your dog may suffer from a decreased appetite (anorexia) if it is experiencing gastritis, which may also cause your dog to act lethargic. In addition to the vomiting, the decreased appetite can lead to weight loss.

Pain

Gastritis can cause severe abdominal pain in dogs, which may cause the dog to arch its back. Your dog's stomach may be tender to the touch as well.

What Causes Gastritis in Dogs?

Acute gastritis is a commonly seen issue in dogs. The majority of cases are caused by dietary indiscretion, which means your dog ate something that it shouldn't have.

Foreign Matter

If your dog eats a foreign, non-food item, it can inflame the stomach lining and cause gastritis. Foreign objects include clothing, rocks, plastics, bones, and paper.

Food

Some foods aren't suitable for dogs and, if ingested, can cause gastritis. These foods include grapes, avocado, chocolate, nuts, and coconut. Even if your dog isn't eating harmful foods, an excess of its regular dog food may also cause inflammation and gastritis. You may also discover that your dog is allergic to an ingredient in its food which can cause repeated inflammation, leading to chronic gastritis.

Toxic Ingestion

If your dog ingests toxic materials, especially items containing chemicals or medications for humans, gastritis can develop. Keep your dog away from substances like Advil, cleaning products, mulch products, and cat litter. Additionally, some plants are toxic to dogs and can cause stomach inflammation. These plants include daffodils, bluebells, and tulips.

Systemic Disease

Several systemic illnesses unrelated to the ingestion of harmful matter can cause secondary gastritis. Conditions like pancreatitis, liver disease, or a viral or bacterial infection can cause dangerous stomach inflammation.

How Do Vets Diagnose Gastritis in Dogs?

Clincal signs of gastritis include vomiting, inappetance, and/or abdominal pain. Your vet will then diagnose your dog's gastritis based on various factors. First, the owner will explain if there is anything they suspect may have caused vomiting, for example, if they have seen their dog eating mulch or watched it ingest a sock. Your vet will run appropriate x-rays, blood work, urinalysis, and stool sampling based on any initial information given. If your vet suspects that something in your dog's regular diet is causing an allergic reaction leading to gastritis, a diet trial with the gradual removal of ingredients, may be needed to diagnose.

Your vet will also check for more serious underlying illnesses causing secondary gastritis. Chronic or acute vomiting is usually enough to indicate the presence of gastritis, but treatment is mainly dependent on its cause. Chronic gastritis will require a more thorough diagnostic process, including evaluation of surgical gastric biopsies.

Treatment & Prevention

Once your vet has identified the inflammatory agent, it will be eliminated from your dog's diet or made physically inaccessible. Many cases of acute gastritis only require treatment of symptoms and can resolve without extensive medical intervention. Your vet may advise that your dog not be fed for 24-48 hours and that once it can eat without vomiting, you should only feed it bland, easily digestible foods. If this doesn't suffice, your vet may also administer antibiotics and anti-vomiting medication. If your dog has become dehydrated from excessive vomiting or cannot keep water down, it may be hospitalized and administered fluid through an IV. If the cause of the gastritis is attributable to a more dire, underlying condition, your vet's treatment plan will address the primary illness and secondary gastritis together.

The only way to prevent acute gastritis is to do your best to ensure that your dog isn't ingesting anything harmful. Even if you do everything right, dogs can still develop gastritis, and a specific cause is not always able to be determined.

Prognosis for Dogs with Gastritis

The prognosis for dogs with acute gastritis is good, while the prognosis for chronic gastritis depends on its underlying cause. Swift and appropriate treatment are essential. Some dogs may need continued therapy even after treatment of symptoms is completed.