Chronic Diarrhea in Dogs: What Causes It and When Should You Call Your Vet?

Although dog diarrhea is not the most appealing topic, it’s a common issue that pet parents should be educated about and know how to address.

Chronic diarrhea—or diarrhea that continues for a longer amount of time than normal—is generally due to an underlying condition that your veterinarian can treat.

What Is Chronic Diarrhea in Dogs?

Chronic diarrhea refers to loose, frequent stools that occur multiple times a day for weeks at a time.

This condition is relatively common among dogs due to the wide variety of potential causes, ranging from stress to underlying medical conditions.

Some dogs may experience just one episode of chronic diarrhea that resolves quickly with appropriate treatment, while other dogs can have recurrent bouts throughout their life that need to be managed.

Causes of Chronic Diarrhea in Dogs

Reasons dogs can develop chronic diarrhea may include:

• Stress or anxiety: Dogs who are stressed or anxious may experience an upset stomach.       

• Diet changes: Dogs who have an abrupt diet change, eat high-fat treats, are fed table scraps, get into the garbage, or eat spoiled food can have diarrhea.

• Foreign body ingestion: If a dog eats something she shouldn’t, it may become stuck inside her intestines, resulting in diarrhea.

• Food allergy: Dogs with underlying food allergies can experience diarrhea due to intestinal inflammation.

• Bacterial infection: When normal bacteria such as Clostridium overgrows in the intestines, it can lead to diarrhea. 

• Pancreatitis: Inflammation of the pancreas results in problems digesting food, which can lead to loose stools. 

• Cancer: Cancers of the stomach and intestines can cause chronic diarrhea as a result of inflammation or blockage.

• Virus: Dogs who are infected with a virus, such as parvovirus, can experience diarrhea as a prominent symptom.

• Medication: Some medications, including antibiotics, can disrupt the normal microflora of the gut and lead to diarrhea.

• Intestinal parasites: Parasites such as giardia and roundworms, which affect the intestines, can lead to diarrhea due to malabsorption and inflammation.

• Inflammatory bowel disease: This autoimmune disease causes inflammation within the intestines, which can lead to diarrhea.

• Exocrine pancreatic insufficiency (EPI): Dogs with this condition do not produce enough pancreatic enzymes, which leads to malabsorption and diarrhea.

• Liver/kidney disease: When a dog’s liver or kidneys do not function normally, waste can accumulate in the bloodstream. The dog’s body tries to flush this waste out through diarrhea.

Small-breed dogs and puppies are more likely to experience chronic diarrhea due to their sensitive stomachs and intestines.

Likewise, German Shepherd breeds are at an increased risk for the condition, which may be due to genetics.

Is Chronic Diarrhea in Dogs an Emergency?

Dogs with persistent diarrhea are more likely to become dehydrated, which is considered a medical emergency.

If pet parents know their dog deals with diarrhea issues, they should watch closely for signs of dehydration that would warrant veterinary attention.

If the dehydration is severe, your dog may require intravenous fluids.

If blood is present in the diarrhea, see a veterinarian promptly to address the underlying cause.

When To Call Your Veterinarian

Pet parents should contact their veterinarian if they notice their dog has diarrhea without a known cause.

For example, if you know your dog accidentally ate some high-fat food that was dropped on the floor during dinner and she now has diarrhea, it should be fine to monitor her for the day to see if stools quickly return to normal.

However, if a dog has multiple episodes of diarrhea, it’s best to see a veterinarian to determine the cause.

It’s important to watch for other concerning symptoms alongside diarrhea, such as:

• Vomiting

• Reduced appetite

• Blood in stool

• Lethargy

• Dry, sticky, or bluish-looking gums

If these symptoms are noticed, contact your veterinarian right away.

How Veterinarians Diagnose Chronic Diarrhea in Dogs

A veterinarian begins with a complete physical exam to check your dog’s overall health.

During this visit, pet parents should discuss whether their dog recently ate anything abnormal, if their dog is taking any medications, and any recent changes to their environment.  

To determine the underlying cause for chronic diarrhea, your veterinarian can perform the following tests:

• Fecal float: A small sample of stool viewed under a microscope to identify intestinal parasite eggs.

• Fecal smear: A sample of stool is checked for overgrowth of bacteria.

• Abdominal ultrasound: A probe is gently placed on the dog’s abdomen to visualize the stomach and intestines. This test is useful to identify inflammation.

• Abdominal X-ray: If your dog has eaten something they shouldn’t have, an X-ray can show the inside of their stomach and intestines.

• Endoscopy: A dog is placed under general anesthesia, and a thin probe is used to see inside the stomach and intestines.

• Diet trial: If a food allergy is suspected, the dog is fed a special diet, like Blue Buffalo™ NP Alligator Dry Dog Food, to see if symptoms improve.

• Trypsin-like immunoreactivity (TPLI) test: This test uses a small sample of blood to check for exocrine pancreatic insufficiency, which could be causing diarrhea.

• Blood work: Blood work can be used to check the dog’s overall health and determine whether protein is lost in the diarrhea.

Treatment of Chronic Diarrhea in Dogs

Dog diarrhea treatment depends on the underlying cause. Any of the following treatments may be recommended:   

• Antibiotics: Medications such as metronidazole may be prescribed for diarrhea.

• Probiotic: Dogs may benefit from daily probiotics, such as Fortiflora®, to maintain a healthy gut.

• Diet change: If a dog is diagnosed with a food allergy, a diet change is necessary.

• Steroids: Many dogs benefit from oral steroids such as prednisone to treat gut inflammation that can lead to diarrhea.

• Deworming medication: If intestinal parasites are diagnosed, a deworming medication such as pyrantel pamoate or fenbendazole will be prescribed.

• Vitamin B12: Supplementing dogs with this vitamin, also known as cobalamin, can resolve chronic diarrhea.

• Surgery: If a dog has cancer or a foreign body, surgery may be needed.

• Supplements: Various supplements to treat EPI, stress and anxiety, and liver or kidney disease may be helpful in eliminating diarrhea.

• Fluid therapy: Many dogs with chronic diarrhea benefit from fluid therapy either given underneath the skin or into the vein.

Prevention of Chronic Diarrhea in Dogs

Pet parents can prevent chronic diarrhea by ensuring their dog receives regular veterinary checkups to identify underlying health concerns early.

Monthly heartworm preventatives with broad spectrum coverage of intestinal parasites, such as Interceptor™ PLUS, are also recommended.

Refraining from feeding your dog high-fat foods and maintaining a consistent high-quality diet can also prevent diarrhea.