Stomach and duodenal ulcers are being diagnosed more frequently in dogs due to the wider use of gastroscopy. Seen through the endoscope, superficial ulcers are patches of inflamed and eroded mucosa covered by white or yellow pus. Deep ulcers are punched-out areas involving all layers of the stomach wall. Ulcers can be single or multiple, and can range in size from less than 1 inch (2.5 cm) to several inches in diameter. Ulcers occur more often in the stomach than in the duodenum.
Bacteria are often the cause of ulcers in humans, but ulcers in dogs are not generally believed to be caused by stomach bacteria-although Helicobacter species have been found in dogs. The usual cause in dogs is corticosteroids or nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin and ibuprofen. Dogs are even more susceptible than people to the ulcer-producing effects of these drugs.
At some time in your dog’s life, it is highly likely that laboratory tests will be performed. These can range from very simple tests, such as fecal checks for parasites or heartworm tests looking for antigens, to sophisticated bloodwork checking out various organs and their functioning. The most common tests done to the blood and urine are discussed here. Blood samples are normally taken from your dog’s vein-either a leg or the jugular vein in the neck. Fasting is recommended before blood tests.
Other conditions that predispose a dog to ulcers include all forms of liver disease, kidney failure, extreme stress (from severe illness or major surgery), chronic gastritis (particularly the eosinophilic type), and shock.
Mast cell tumors of the skin can cause ulcers. This is because these tumors produce and release histamine, which is a powerful stimulant to acid secretion. In fact, ulcers occur in up to 80 percent of dogs with mast cell tumors.
The principal sign of an ulcer is sporadic or chronic vomiting. Dogs may also lose weight and be anemic. In dogs with nonspecific signs, such as chronic vomiting, the diagnosis is made by gastroscopy.
Occasionally the vomitus contains old blood (which looks like coffee grounds) or fresh blood and blood clots, although the bleeding in many ulcers is microscopic. With rapid bleeding the dog goes into shock and passes black, tarry stools. Stomach and duodenal ulcers can rupture into the abdomen, causing peritonitis.
Treatment: Perforated ulcers require emergency surgery. Dogs with gastrointestinal bleeding should be hospitalized for observation and further tests. Severe anemia is treated with blood transfusions. It is important to identify and eliminate predisposing causes. Discontinue all ulcer-producing medications.
Ulcer drugs used in people are effective in dogs. They include the histamine blockers Tagamet (cimetidine), Pepcid (famotidine), and Zantac (ranitidine); the mucosal protectants Carafate (sucralfate) and Cytotec (misoprostol); Prilosec (omeprazole); and antacids such as Mylanta, Maalox, and Amphogel. These drugs are best taken in combination (an antacid along with a histamine blocker), several times a day. A veterinarian should determine the most effective drug combination and schedule. Treatment is continued for at least three to four weeks. A follow-up gastroscopy is advisable to ensure that healing is complete.
WebMD Veterinary Reference from "Dog Owner's Home Veterinary Handbook"