Diarrhea in Dogs

What is diarrhea?

Diarrhea is unformed or loose stools that occur in larger amounts or more often than usual. Diarrhea is not a disease, but rather a sign of many different diseases.

Diarrhea associated with minor conditions can often be resolved quickly with simple treatments. Diarrhea may also be the result of serious or life-threatening illnesses, such as organ system failure or cancer. Even diarrhea caused by mild illnesses may become serious if treatment is not begun early enough.

How can I tell if my dog has diarrhea?

If your normally well-trained dog suddenly starts having accidents around the house and the stools are unformed or fluid, then diarrhea is obvious. However, if the dog defecates outdoors, you may not initially notice diarrhea. In long-haired breeds, you may notice staining or soiling of the fur around the back end.

It is important to remember that some variation in the consistency of stools occurs in healthy dogs. If frequent liquid or semi-liquid stools persist for more than two days, you should consult your veterinarian.

What causes diarrhea?

Diarrhea is the result of faster movement of fecal material through the intestines, combined with decreased absorption of water, nutrients, and electrolytes. Common causes of diarrhea in dogs include:

• Infection with bacteria, viruses, coccidia, or parasites such as worms (hookworms, roundworms, whipworms)
• Non-infectious irritants, such as chemical toxins or poisonous plants
• Changes in diet or food intolerances
• Dietary indiscretion (eating garbage or other offensive or irritating materials)
• Stress, especially following travel, boarding, or other changes in the environment

Diarrhea can also be a sign of a more serious underlying disorder such as food allergies, severe bacterial or viral infections (such as parvovirus), inflammatory bowel disease, organ dysfunction, cancer, or other systemic illnesses.

How serious is diarrhea in dogs?

The seriousness of diarrhea depends on how long it persists and how many other clinical signs accompany it. If your dog has severe, bloody diarrhea or shows more generalized signs of illness, the cause may be serious, and you should seek medical attention as soon as possible. For example, diarrhea is one of the first signs seen in parvovirus, a viral infection that can cause life-threatening illness in susceptible dogs. Generalized signs of illness may include:

• Weakness
• Fever
• Vomiting
• Abdominal pain
• Dehydration
• Loss of appetite
• Weight loss

How is the cause of diarrhea diagnosed?

Your veterinarian will diagnose the cause of diarrhea by reviewing your dog’s medical history, performing a physical examination, and in some cases, taking samples for laboratory testing. The nature of the diarrhea, such as its color, consistency, smell, and frequency, is important in determining the cause.

Your veterinarian will likely request a sample of fresh fecal material to be brought to your appointment. You may also be asked a series of questions about your pet's diarrhea, such as when the diarrhea started, how often it occurs, what it looks like, and any recent changes in your pet's diet or environment.

In mild cases of diarrhea, your veterinarian may not perform further diagnostic testing unless initial treatment fails or the condition worsens. Additional tests may include bloodwork, stool and rectal swab samples for parasite examination, DNA testing for infectious organisms, bacterial culture, radiographs (X-rays), ultrasound, and endoscopic exam.

How is diarrhea treated?

For otherwise healthy adult dogs, your veterinarian may advise you to withhold food for a short time or to feed small amounts of a veterinary diet for gastrointestinal problems. These diets are specifically formulated with a balance of fibers that feed the good bacteria in your dog’s intestine and certain antioxidants that support your dog’s immune system. It is important to always provide easy access to water, because a dog with diarrhea can quickly become dehydrated.

Medications and supplements may be prescribed, such as anti-diarrheal agents, de-wormers, and probiotics (bacteria that support intestinal health). There are several probiotic products that may help dogs with diarrhea. However, consult your veterinarian before offering anything to your dog, as the quality and effectiveness of these products are not always known.

Many cases of acute (sudden) diarrhea respond well to this conservative treatment, allowing the body's healing mechanisms to correct the problem, without the initial cause ever being established. As the stools return to normal, you can usually transition back to your dog’s regular diet over seven to ten days.

If your dog does not improve within two days, your veterinarian may recommend further testing or more aggressive treatment. Severe or prolonged diarrhea can result in significant dehydration and other problems caused by fluid loss, and your dog may require hospitalization for intravenous fluid therapy or other, more intensive, treatments.

What is the prognosis?

The prognosis depends on the severity of the diarrhea, the specific diagnosis, and your dog's response to treatment. Most dogs with simple diarrhea will make a full recovery, while dogs with chronic diarrhea may require long-term dietary management or medications to keep the condition under control.