This article was updated on August 26th, 2023
As an emergency veterinarian, I frequently see dogs being brought to the emergency room to investigate the causes of bleeding from their hind ends. While this is a presenting complaint that is all too common for me, the sight of blood often frightens most pet owners – and rightfully so! Let’s discuss common reasons why dogs may bleed from their bottoms and what owners can do about it.
Top reasons resulting in blood in your dog’s bottom, and what it looks like
Bleeding from a dog’s rectum may occur for a variety of reasons. The most common causes of bleeding include:
1. Hemorrhagic Diarrhea
Hemorrhagic diarrhea, also known as Acute Hemorrhagic Diarrhea Syndrome (AHDS), is a common cause of bleeding from a dog’s anus. This condition is characterized by large amounts of bloody diarrhea and may be accompanied by vomiting or anorexia. When diarrhea occurs, it is typically secondary to an underlying condition causing inflammation of the colon. This diarrhea causes increased urgency to go to the bathroom and straining to defecate. Straining can cause worsening inflammation and discomfort of the colon/anus leading to more blood in the stool. A hallmark sign of AHDS is diarrhea that appears similar to raspberry jam.
Diarrhea with blood can occur for a variety of reasons, including dietary indiscretion, food intolerance, chronic gastrointestinal disease, parasitism, pancreatitis, stress, antibiotic use, and other systemic illnesses. Learn more: My Dog Has Bloody Diarrhea.
Opposite to the above, constipation is also a common cause of bleeding from the anus. Constipation is caused by the inability to defecate normally, either due to hard feces, disease of the rectum, anal obstructions, pain when defecating, or neurological/orthopedic disease. Dogs that are constipated may strain to defecate with little to no production of feces. Bowel movements may be painful, and blood can be produced from breaking blood vessels in the rectum while straining. View our recommended home remedies to help a constipated dog.
3. Anal sac disease
Dogs have two anal sacs situated on either side of their anus. These glands help with the lubrication of feces as well as scent marking during defecation. For a variety of reasons, these glands can become impacted or infected. Infected anal glands can develop into abscesses which can rupture and bleed. Dogs may scoot, lick, or chew, leading to ulceration and bleeding of the perineal region.
4. Perineal Fistulas
Perineal fistulas are caused by an auto-immune condition that leads to severe inflammation and ulceration of the perineal region. Dogs with this condition will develop tracts alongside the anus, which will often have foul-smelling discharge and can lead to bleeding, straining to defecate, and significant pain. German Shepherds are predisposed to this condition.
There could also be other reasons causing bleeding in your dog’s bottom, so it is important that you call your veterinarian to schedule an appointment as soon as possible.
Can I just monitor my dog and wait? Is my dog in danger?
Mild cases of rectal bleeding rarely require urgent veterinary intervention. Dogs with signs of ongoing bloody diarrhea, pain, frank blood when defecating, vomiting, vomiting and diarrhea, or black/tarry stools require urgent veterinary intervention. Waiting may lead to increased discomfort, pain, dehydration, and worsening of their overall condition (making it harder to treat your dog’s condition). Dogs with severe AHDS can become dehydrated quickly and even die from this illness.
Signs that you should be concerned about the blood you are seeing in your dog’s bottom
Rectal bleeding is always concerning to pet owners but is not always an emergency. The following clinical signs indicate that urgent or emergent intervention is required:
- Defecating large amounts of blood – A small amount of blood in the stool can be seen with mild inflammation of the colon and is not overly concerning. A large amount of blood in your dog’s poop is a sign of significant inflammation of the colon or damage to the local blood vessels. This should always be addressed by a veterinarian. Read this article if you can see blood in your dog’s poop, but your dog is acting normal.
- Pain – Any dog that is showing signs of pain or discomfort should be evaluated by a veterinarian as soon as possible.
- Constipation – Dogs that cannot defecate for more than 24 or 48 hours require urgent intervention. Constipation can lead to significant discomfort, anorexia, and vomiting. Learn about remedies to help a constipated dog and when to call your vet.
- Perineal fistulas – If you are concerned that your dog has a perineal fistula, urgent intervention is recommended. Catching the disease in its early phases will allow quicker diagnosis and treatment. This may halt the disease in the early phases leading to quicker relief for your pet and potentially a better response to therapy.
Veterinarian’s Tip: Perineal fistulas are an autoimmune condition that is very painful. These dogs need to see a veterinarian as soon as possible and may require lifelong treatment.
5 steps you can take at home to help your dog
- Diet change – Dogs with simple diarrhea with a small amount of blood may benefit from remedies at home (read: Dog has bloody diarrhea but acts normal). The easiest and most effective treatment an owner can provide is changing their dog’s meals to a bland diet. This diet typically consists of boiled chicken or lean ground beef mixed with white rice. An easily digestible diet may improve most cases of simple diarrhea after a day or two.
- Fiber supplementation – Another simple over-the-counter solution to various causes of diarrhea and constipation includes the addition of fiber to the diet. Fiber supplements such as psyllium husk can improve fecal quality and texture. This can lead to improvements in diarrhea or decrease the likelihood of constipation.
- Probiotics – Bloody diarrhea can because caused by an imbalance of bacteria in the gastrointestinal tract. When bad bacteria outcompete the good, inflammation of the gastrointestinal tract can occur, leading to diarrhea. A simple solution is to provide canine-specific probiotics as a means of replenishing healthy bacteria and restoring gut health.
- Preventative measures – The best way to prevent anal irritation and bleeding is to try to prevent diseases that cause it in the first place. This means avoiding food items that can cause upset stomachs leading to diarrhea. Monthly flea and tick preventatives will decrease the likelihood of diarrhea from gastrointestinal parasites.
- Anal gland expression – Dogs who frequently experience anal gland problems benefit from routine anal gland expression. Scheduling expressions at your veterinary office can decrease the likelihood of impaction or abscess formation. Pumpkin and probiotics might help with a dog’s anal gland issues.
How to prepare for your veterinarian visit
Before your veterinary visit, make sure you have any information handy that your veterinarian may need. This includes a timeline and details of the clinical signs as they appeared. Photos of the blood or feces may be helpful for the doctor to have a better sense of what is going on. Bringing a fresh fecal sample will facilitate testing for parasites or bacterial overgrowth.
How the Vet Can Help & How Much It Costs
At the veterinary office, a series of steps will take place to determine the cause of your dog’s anal bleeding. First, your veterinarian will take a thorough history to help decipher what the underlying cause may be. After they have an understanding of what has been going on, a physical examination will be performed. Part of this physical examination will include a rectal exam. This exam is used to determine if there are any abnormalities of the anus, anal glands, or stool. Your veterinarian may request a fecal sample to evaluate for gastrointestinal parasites or overgrowth of bacteria. If the anal glands are abnormal, expression may be performed to alleviate discomfort. In the event of an anal gland impaction or abscess, your dog may need to be sedated to have the anal sac drained.
Once a definitive diagnosis is made regarding the cause of your dog’s bleeding, a targeted treatment plan will be discussed. This may include medication or probiotics to improve diarrhea, pain medication, or deworming agents to eliminate gastrointestinal parasites. Dogs with perineal fistulas may require treatments with immunosuppressive agents.
Learn more: Dog Has Red or Inflamed Anus: What to Do