Bloody Diarrhoea in Dogs: Causes and How to Manage It

What Does Bloody Diarrhoea Look Like in Dogs?

Blood in stool is never normal. Bloody diarrhoea in dogs is characterised by watery, loose stools with blood and sometimes contains mucus. This condition results from inflammation and irritation of your dog’s gastrointestinal (GI) tract, leading to blood in stool during normal digestion.

The colour of stools is an important indicator of where the bleeding occurs. Bright red colouration indicates that the blood has not been digested, meaning it originates in the lower intestines or rectum. Meanwhile, dark stools suggest bleeding in the upper GI tract (such as the small intestine), as the blood has been digested. The presence of mucus may also point to bleeding or irritation in the colon.

Bloody diarrhoea is generally considered a medical emergency, even if your dog appears normal. In some cases, your dog may also have other signs such as vomiting, inappetence or straining to defaecate. Take your dog to a veterinarian immediately for a detailed diagnosis and prompt treatment to prevent the condition from worsening.

Common Causes of Bloody Diarrhoea in Dogs

Dogs can develop diarrhoea for various reasons, ranging from stress and dietary changes to more severe cases, such as an infection or illness in the GI tract.

Food Allergies

Like humans, dogs may also be allergic to certain foods, some of which can trigger severe reactions, including diarrhoea. Knowing your dog’s allergies can help you prevent these reactions from recurring.

Inflammatory Bowel Disease (IBD)

IBD refers to chronic irritation and inflammation of your dog’s GI tract. These inflammatory cells invade the wall of the GI tract, causing thickening. This reduces the ability of the GI tract to absorb nutrients and move food along. Symptoms may include chronic vomiting, chronic diarrhoea, lethargy, poor appetite, and weight loss. This can be due to an infection or an allergic reaction. In most cases, an exact underlying cause cannot be determined.

Infection

Certain bacteria, viruses, and parasites may also infect your dog through various transmission vectors, such as contact with other animals or ingestion of spoiled food. Parasites is a common cause of infections in young puppies. Infections greatly increase the risk of bloody diarrhoea, as these harmful microorganisms can damage the intestinal lining or cause other digestive problems, leading to bloody stools, vomiting, and dehydration.

Dietary Indiscretion

Dogs may accidentally eat something they should not consume out of curiosity or mischief, which can irritate their digestive system and lead to complications. Consuming spoiled food, foreign objects, harmful toxins, or garbage can increase the risk of digestive complications, including severe bloody diarrhoea. Even sudden dietary changes, like switching to a different type of dog food, can easily irritate their digestive tract.

Stress

Sudden changes to your dog’s daily routine and travel anxiety are among the many things that can cause stress. While some stress can be managed, long-term stress might increase the risk of gastrointestinal upset, which may include colitis (inflammation of the colon) and stomach or intestinal ulcers that can cause bleeding. Removal of the stressor often results in resolution of signs.

Other Conditions

There may be other reasons why your dog suddenly has bloody diarrhoea, including (but not limited to):

• Intestinal blockage

• Certain medications

• Liver shunts

• Cancer

• Bleeding disorders

• Toxin ingestion

• Sepsis and multi-organ failure

It is vital to take your dog to the vet as soon as you notice blood in their stools.

How Our Vets Diagnose the Cause of Bloody Diarrhoea

Physical Examination

A physical examination allows the vet to determine how sick your dog is. This includes an assessment of your dog’s vital parameters, if there is presence of dehydration, and for abdominal pain. The vet will also review your dog’s medical history to look for other signs that may indicate the cause of the bloody diarrhoea and rule out other conditions.

Blood Tests

Blood tests are routinely done to assess the level of dehydration, assess organ function, and to evaluate for signs of inflammation and infection. In severe cases of bleeding, a low red cell count may be seen, and additional blood tests to check for blood clotting function will be indicated.

Imaging Tests

The vet may use X-rays or ultrasound imaging to look for specific signs that may point to the cause of your dog’s bloody diarrhoea. Imaging can also be used to rule out other conditions that may present with similar symptoms, or to look for foreign objects your dog may have ingested.

Stool Analysis

The vet may collect a stool sample from your dog for further testing to look for intestinal parasites or bacteria that may be causing the bloody diarrhoea. This test can help to narrow down the diagnosis and rule out other conditions that exhibit similar symptoms.

Treatments for Bloody Diarrhoea in Dogs

Prompt treatment with the supervision of a qualified veterinarian aims to stabilise your dog’s condition and support their gradual recovery.

Intravenous (IV) Fluid Therapy

A large amount of fluid is lost with diarrhoea. Fluid therapy is vital in the treatment of diarrhoea to restore hydration safely. If left untreated, dehydration can have serious consequences. Electrolyte supplementation is often required as part of fluid therapy. In severe cases, patients may have to stay in hospital for a period to allow for continued replenishment of fluid while they recover from the diarrhoea.

Parasite Management

Dewormers or anti-parasitic medications are prescribed to dogs with parasitic involvement.

Medications

Depending on the underlying cause of the diarrhoea, medications will be prescribed accordingly. Symptomatic treatment of diarrhoea includes medications that soothe the irritated GI tract lining and firm up loose stools.

Dietary Management

Managing your dog’s diet may also help prevent bloody diarrhoea. Put your dog on a bland diet of easily digestible foods that provide the essential nutrients they need to stay healthy. Your vet can provide recommendations on what your dog can eat and what they should avoid.

It is also essential to let your dog transition slowly to new foods to prevent further GI irritation.

When to Seek Immediate Veterinary Attention

If your dog exhibits any of the following signs or symptoms, take them to the vet immediately to prevent further complications.

• Blood in stool

• Frequent diarrhoea

• Straining to defaecate

• Lethargy or weakness

• Poor appetite

• Vomiting alongside diarrhoea

• Abdominal pain

• Weight loss

Puppies, senior dogs, and dogs with existing health conditions are at higher risk of complications from bloody diarrhoea, so prompt medical treatment is essential. Visit Westside Veterinary Emergency and Referral Hospital to learn more about how we can help treat bloody diarrhoea in dogs.