Gastritis is quite common in dogs due to their indiscriminate (not selective) eating habits. It is not uncommon for a normal healthy dog to have occasional bouts of acute gastritis over the course of their life, especially if they are longhaired or have a habit of getting into the trash. As long as they are short lived and self limiting, we tend to consider these "normal abnormalities". One must differentiate acute from chronic gastritis, as well as gastritis from regurgitation (the backward flow or effortless evacuation of fluid, mucus, or undigested food from the esophagus) as there are different diseases, diagnostics, and treatment plans for each.
In those dogs who are otherwise feeling well, symptomatic therapy, to include removing all food and water for a specified amount of time and gradually reintroducing a bland diet, is generally curative. If the dog continues with signs of gastritis (vomiting, lack of appetite, nausea), despite being held off food and water, or if blood is present in the vomitus, it is important to seek veterinary attention at once. In addition, if your dog seems painful, in distress or sick in any other way, you should contact your veterinarian immediately as diagnostics, hospitalization and supportive therapy may be in order.
There are several disorders/diseases that can cause similar signs and may be confused with gastritis. These include; Dietary indiscretion (ingestion of spoiled food, plant material, hair, or overeating) is one of the most common disorders seen in both cats and dogs. Vomiting, diarrhea and flatulence are commonly seen associated with dietary indiscretion.
Dietary intolerance or allergy to a particular food or substance often is associated with vomiting and/or diarrhea.
Infectious disorders that affect the gastrointestinal tract including viral, bacterial, fungal and parasitic infections must be differentiated from gastritis.
Pancreatitis is an inflammation of the pancreas, and in certain cases, can be life-threatening. The most common clinical signs seen with pancreatitis are vomiting and inappetence.
Metabolic disorders (kidney failure, liver disease, hypoadrenocorticism, diabetes mellitus) are often associated with vomiting, inappetence and weight loss, all of which are signs commonly seen with gastritis.
Intestinal obstruction/blockage secondary to foreign bodies or tumors must be differentiated from gastritis.
Infiltrative diseases (microscopic diseases that penetrate and spread throughout) of the gastrointestinal tract including inflammatory bowel disease and lymphosarcoma (cancer) must be ruled out.
Gastrointestinal ulcers can be associated with liver and kidney disease, pancreatic disease, stress and certain types of cancer. Clinical signs associated with ulcers include vomiting (possibly with blood), melena (black tarry stools due to digested blood), abdominal pain, weakness and potential collapse and death.
Pyloric hypertrophy is a thickening of the part of the stomach that empties into the small intestine, causing vomiting. It is most commonly seen in small-breed dogs (lhasa apso, shih tzu, Maltese and the miniature poodle.)
Hemorrhagic gastroenteritis is a syndrome seen in dogs whose cause is unknown. These animals often present with vomiting and bloody diarrhea. Hemorrhagic gastroenteritis is most often seen in urban settings.
Neurologic disorders, especially of the vestibular (balance and coordination) center will often present for vomiting.
Certain medications or toxins (such as lead) can cause severe gastrointestinal signs by either directly irritating the lining of the stomach (such as with aspirin administration) or by setting off a reflex mechanism that stimulates the vomiting center of the brain.
Pain, fear or other psychogenic disturbances can cause gastrointestinal upset, and mimic or cause signs of gastritis.