Why Is My Dog Bleeding From Its Anus? - Causes

Why Is My Dog Bleeding From Its Anus? - Causes

Rectal bleeding in dogs, wherever it occurs, is always cause for alarm among pet guardians. A dog may bleed from its rear end due to many different reasons. The origin of the blood, however, can differ. Therefore, if your dog is bleeding from its rectum it is incredibly important that you go to a veterinarian as soon as possible. A veterinarian will be able to make a correct diagnosis and treat the symptoms accordingly.

However, for more information, we here at AnimalWised wanted to explain some of the possible reasons why your dog is bleeding from its anus. We will be covering common causes of rectal bleeding, differentiating where the blood is really coming from and what you can do about it.

There are different reasons why a dog may be bleeding from the rectum, each related to different a source within the dog's body. We are going to discuss the most common causes for anal bleeding in dogs, which are:

  1. Hemorrhage in the digestive system
  2. Constipation
  3. Infection of the anal glands
  4. Other causes (rectal bleeding along with vomiting)

1. Dog rectal bleeding - Hemorrhage in the digestive system

The digestive system of a dog starts at its mouth, continues down the esophagus to the stomach, small intensive, large intestine and ends at its anus. If there is a hemorrhage in any part of this system, including the nasal cavity or lungs, the blood will be expelled through the dog’s anus.

Therefore, the cause of bleeding in a dog's rear end can originate from several different areas within their body. This is why a diagnosis is so incredibly important. In order to proceed with a diagnosis, it is important to check the texture and presentation of the stool itself. Blood in a dog’s feces is medically classified into two types: hematochezia or melena.

  • Hematochezia causes the expulsion of fresh, red and bright blood that can appear in normal stools or as bloody diarrhea. This blood in the dog's stool usually comes from the colon, rectum or anus.
  • Melena causes a dog’s feces to appear black or tarry. This color suggests that the blood is coming from the upper intestinal tract.

In order to diagnose dog rectal bleeding effectively, one also needs to notice whether the blood is mixed with the feces, or on the outside of the feces, and what color the blood is. These all function as signs which can help you work out the cause of your dog bleeding from its bottom.


2. Rectal bleeding in dogs - Constipation

Is your dog bleeding from its rear end? Constipation may be one of the main causes. You can tell whether your dog is constipated by noticing that the dog does not defecate at all, or does so in a small amounts, with obvious difficulty. The effort it takes the dog to defecate can often cause bleeding from its rectum.

Constipation in dogs can be caused my many different things, one being dehydration. Dehydration in dogs can can cause a dog’s stool to dry up, which will naturally make it difficult to expel. This can cause slight rectal bleeding. For more, take a look at our article on signs my dog is dehydrated.

If a dog swallows bones, tissues and other substances which are difficult or impossible to digest, this can cause bleeding in the dog’s anus. Some medications can also result in constipation as a side effect. In addition, there many diseases which can cause constipation. These include diseases such as hypothyroidism and specific digestive diseases.

If you observe rectal bleeding in dogs, pain when defecating and/or painful efforts to defecate, we suggest visiting your veterinarian as soon as possible. If your dog is in fact suffering from constipation, a doctor will be able to treat this effectively. You can also prevent constipation in your dog by following these tips:

  • Provide correct diet and hydration that facilitates the intestinal transit.
  • Avoid feeding them bones.
  • Schedule regular veterinary reviews that can detect diseases in time.
  • Maintain a safe environment to prevent the ingestion of foreign bodies.
  • Never medicate a dog without veterinary supervision.
  • Give your dog sufficient opportunity to defecate and exercise.

3. Canine rectal bleeding - Infection of the anal glands

A dog has two two glands or sacs located on both sides of the anus. When feces are expelled, it can exert pressure on these glands. These glands then empty a liquid to aid with lubrication. Sometimes, however, the anal glands can become infected, which may explain why a dog starts bleeding from the rectum. In these cases, the dog will feel pain and a yellow or bloody discharge will be released. A dog suffering from this problem will also most likely rub or drag its bum on the ground or lick the infected area. A veterinarian will be able to drain the glands and administer appropriate antibiotics to cure any infection[1].

Often, if the inflammation targets only one gland, it could mean that the dog is suffering from an abscess. This abscess can break the skin, producing a perianal fistula from which a foul-smelling liquid will emerge. If this is the case, it is very important to go to the veterinarian as soon as possible, as in severe cases an abscess may require surgery. Disinfection and the administration of antibiotics will also be necessary to treat abscesses[2].

My dog is bleeding from the rectum and throwing up

If you notice your dog bleeding from its rectum and vomiting, then it is critical to take them to veterinarian as soon as possible. Rectal bleeding in dogs partnered with vomiting can be a sign of various conditions or diseases, such as:

  • Ulcers in dogs: these are lesions in the mucous membrane of the digestive system, often caused by the use of medications such as corticosteroids, but also by diseases such as kidney or liver failure. They can cause vomiting, anemia, thinning as well as anal bleeding.
  • Canine parvovirus: this condition mainly affects puppies and is characterized by the presence of vomiting and bloody diarrhea. It is a very serious and contagious, and vaccination is essential to prevent it.
  • Dog poisoning: the ingestion of some toxins can cause symptoms such as rectal bleeding in dogs and/or vomiting blood. Immediate veterinary assistance is required as dog poisoning can be fatal.
  • Heat stroke in dogs: an excessive rise in the body temperature of a dog produces, among other symptoms, vomiting and diarrhea with blood in the stool. This can happen when, for example, a dog is left inside a closed car during the hottest hours of the day. Heat stroke should be treated immediately as it can result in death.
  • Renal insufficiency in dogs: Kidney failure in dogs can also cause vomiting and the presence of blood in feces, due to causes such as gastrointestinal hemorrhages. These hemorrhages need to be stabilized by appropriate veterinarian treatment. For more, take a look at renal failure in dogs.

This article is purely informative. AnimalWised does not have the authority to prescribe any veterinary treatment or create a diagnosis. We invite you to take your pet to the veterinarian if they are suffering from any condition or pain.

If you want to read similar articles to Why Is My Dog Bleeding From Its Anus? - Causes, we recommend you visit our Other health problems category.

  1. Jung, Y., et al. (2016). Diagnostic imaging features of normal anal sacs in dogs and cats. Journal of Veterinary Science, 17(3), 331-335.
  2. Rannou, B. and Bédard, C. (2009). Rectal plasmacytoma with intracellular hemosiderin in a dog. Veterinary Pathology, 46(6), 1181-4.