Bloody Diarrhea in Dogs

Sick puppy
Puppies may develop bloody diarrhea. Lumenphoto/Getty Images

Bloody diarrhea is not fun for a dog to have nor is it enjoyable for the dog owner to clean up. Diarrhea can be temporary or chronic and the color of the stool often tells us more about the underlying cause of it. Bloody diarrhea is especially concerning for dog owners since blood is not a normal part of feces but while there are serious reasons why blood may be noted in the stool, it isn't always a cause for panic.

Causes of Bloody Diarrhea in Dogs

The blood component of bloody diarrhea can appear as bright red blood called hematochezia or as black blood which is referred to as melena. Hematochezia is a result of bleeding in the lower digestive tract while melena starts in the upper digestive tract. Blood that occurs in melena gets digested and turns black before appearing in the diarrhea. Bloody diarrhea of both types can be caused by a multitude of things.

  • Stress - Just like in people, stress can cause a dog's bowels to secrete excess fluid along with blood from inflammation. This is often referred to as stress colitis.
  • Intestinal parasites - Various worms and protozoan, such as giardia and hookworms, can cause bloody diarrhea. This is because these parasites often feed off of the intestinal wall.
  • Bacterial and viral infections - Various infections, such as salmonella, E. coli, and parvovirus can all cause bloody diarrhea.
  • Trauma - If a dog experiences some sort of injury or has surgery on the digesting tract it is not unlikely that the dog will have bloody diarrhea as a result.
  • Tumors - Tumors in the digestive tract often bleed and disrupt normal digestion which can cause diarrhea along with blood to appear.
  • Bowel inflammation - Any type of inflammatory condition affecting the bowels can cause bloody diarrhea.
  • Toxins - Ingestion of poisons or any food that is considered to be toxic to a dog may create bleeding issues or bloody diarrhea due to the negative effects it is having on the body.
  • Anal gland problems - Anal glands are located in the rectal tissue and if they become infected, impacted, or inflamed, bloody diarrhea may result.
  • Straining to defecate - Anytime a dog strains to defecate it could burst small blood vessels around the rectal area. This commonly occurs when a dog has diarrhea and strains.
  • Cancer - Many kinds of cancer can affect the digestive tract and unfortunately cause several issues including bloody diarrhea.
  • Dietary indiscretion - If a dog eats something it doesn't normally eat it may develop some intestinal irritation or inflammation and have bloody diarrhea.
  • Ulcers - Stomach and intestinal ulcers can cause diarrhea and bleeding.
  • Foreign bodies - If a dog eats an object that is not digestible it can become stuck in the digestive tract and even cause trauma inside the body. This can result in bloody diarrhea.
  • Side-effects from medications - It is not uncommon for medications to have side effects, one of which could be bloody diarrhea.
  • Pancreatic disease - Since the pancreas plays an important role in digestion, if this organ gets inflamed or doesn't work properly bloody diarrhea may result.
  • Liver disease - Severe liver disease may cause bloody diarrhea as the liver is unable to function properly.
  • Kidney failure - Severe forms of renal disease can cause bloody diarrhea.
  • Addison's disease - An uncommon endocrine disorder, Addison's affects the adrenal glands and may cause bloody diarrhea in dogs.
  • Blood clotting disorders - Some dogs that have clotting disorders may develop bloody diarrhea more easily than other dogs.

Diagnosing Bloody Diarrhea in Dogs

Bloody diarrhea is usually diagnosed by visually inspecting the stool. Bright red blood is quite obvious to see in most stool but black, digested blood may be less apparent. If digested blood or a very small amount of red blood is suspected, your veterinarian may perform a test called a fecal occult blood test that says whether or not blood is detected in the feces.

Treatment of Bloody Diarrhea in Dogs

Depending on the cause of the bloody diarrhea, treatments will vary. Surgical intervention may be necessary for tumors, foreign bodies, and cancer, dietary changes may be made to increase fiber intake, and medications may be used to kill parasites, treat diseases, and remedy symptoms. Fluids are also sometimes needed in pets that are dehydrated due to the diarrhea.

How to Prevent Bloody Diarrhea in Dogs

The best way to prevent a dog from developing bloody diarrhea is to make slow food transitions, keep foreign objects and toxins that it may consume out of its reach, monitor its stress level, feed appropriate foods, use regular intestinal parasite preventatives, and have regular check-ups with a veterinarian.

If you suspect your pet is sick, call your vet immediately. For health-related questions, always consult your veterinarian, as they have examined your pet, know the pet's health history, and can make the best recommendations for your pet.