Skip to main content

Should I Be Worried About Blood in My Dog's Urine?

Sophie Jackson is a dog lover and trainer living in the UK. She competes in agility and obedience with her four dogs.

Blood in a dog's urine can be an early sign of something wrong.

Blood in a dog's urine can be an early sign of something wrong.

Blood in Urine?

It can be a worrying moment when your dog squats or lifts its leg to urinate, and you notice there is an ominous red coloration to the result. Maybe your dog has been lying on the floor or the sofa and when they move a red stain is visible.

Any time our dogs pass blood it is natural to worry. While some causes of passing blood are harmless, it can be an indication of illness, anything from a water infection (UTI) to something more serious such as cancer.

Blood in urine should be something all dog owners are alert to as it is an early indicator of something being wrong.

Female dogs may leave spots of blood behind when in season.

Female dogs may leave spots of blood behind when in season.

Ruling Out the Obvious: Is Your Dog in Season?

If you have a female dog who has not been spayed, then noticing spots of blood where she has been lying or sitting might indicate she is in season rather than a water infection. If your dog is young, it could be her first season and many owners are startled at the sight of blood under their dog.

How can you tell the difference between a UTI and a normal season and know when you should go to the vet?

Firstly, blood expelled during a dog's season comes from her reproductive system, rather than her urinary system. It is less likely you will notice blood in her urine, but rather will see spots on the floor or furniture where she has been sitting. Other signs that your girl is in season include:

  • A swollen vulva (the area where she pees from)
  • Interest from or in male dogs
  • Swollen nipples
  • Behavior changes (clingy, sleepy, anxious)

Seasons last around three weeks, with bleeding typically in the first week, which then stops by the second, but may begin again in the third week. Using this pattern and the other symptoms listed above, you should be able to determine if your dog is having a season, though if the symptoms persist or you have any concerns see your vet.

UTIs are common in older dogs, especially female dogs.

UTIs are common in older dogs, especially female dogs.

Urinary Tract Infections: The Commonest Cause of Blood in Urine

In male and female dogs, blood in the urine is often a sign they have a urinary tract infection (UTI). This means that an infection has started somewhere within the system that controls the processing and passing waste fluid. People sometimes refer to this as a water infection.

The infection could be based in the bladder, kidneys, prostate (male dogs only) or within the tubes that allow urine to pass out of the body.

Other symptoms of a UTI include:

  • pain when passing fluid
  • incontinence (loss of bladder control)
  • licking themselves
  • lack of energy
  • loss of appetite
  • weight loss
  • fever

In some cases of UTI, peculiar behavior changes occur which can be confused in older dogs with signs of dementia. They might bark at shadows, stare at the walls, or seem generally uneasy.

Older dogs, in general, are more prone to UTIs, with older female dogs being slightly more predisposed to developing them. Also, dogs with diabetes are far more likely to develop UTIs.

UTIs are not self-resolving and require a trip to the vet for antibiotics. Occasionally the infection can be difficult to eradicate with just one dose of antibiotics and may require different types to fully remove it.

Bladder or Kidney stones can cause a lot of discomfort.

Bladder or Kidney stones can cause a lot of discomfort.

Kidney and Bladder Stones

When signs of infection are not present, a possible cause of blood in the urine are stones that have formed in the kidneys or bladder. These stones are rock-like formations of minerals. They can be small and numerous (described as gravel) or they can turn into one large stone.

The stone or stones restrict the dog's ability to pass urine and rub against the walls of the organs they are in, causing damage and resulting in blood being passed. It is thought to be a very painful condition and can be life-threatening if a large stone blocks the tubes connecting either to the kidneys or bladder, preventing urine from being expelled.

A UTI may develop due to the problems caused by the stones and this can lead to difficulty diagnosing the condition.

There are three ways stones are treated

  1. Surgical removal of the stones: This may not be suitable for patients with other health concerns or who would not do well under a general anesthetic.
  2. Small stones can be flushed out by your vet using a special medical tool. This still requires sedation
  3. A special diet can be fed which dissolves the stones, however, this is dependent on the type of stone that is present. It is also a slow process and does not always work.

If the stone is causing a blockage and is preventing your dog from passing urine then emergency surgery to remove it is the only option to save their life.

Prostate problems are found in unneutered male dogs, but are usually not life threatening.

Prostate problems are found in unneutered male dogs, but are usually not life threatening.

Problems With the Prostate

Entire (unneutered) male dogs can sometimes develop issues with their prostate, which is a small gland near the neck of the urinary tube, sitting behind the bladder. In dogs that have not been neutered the prostate can become enlarged, this causes difficulty passing urine and also sometimes pooping.

There are several reasons the prostate can become enlarged, fortunately, most are easily treated.

  • Benign Prostatic Hyperplasia (BPH): This is the commonest cause of an enlarged prostate. It is caused by the hormone testosterone and can be cured by neutering the dog. It can also be managed with medication where neutering is not advisable.
  • Squamous metaplasia: Similar to BPH (above) but this enlargement is caused by the hormone estrogen and is usually associated with a testicular tumor that is producing the hormone. Again, neutering to remove the tumor will resolve the problem.
  • Paraprostatic Cysts: These are normally present from birth and are found next to the prostate. They do not tend to cause problems until the dog is older. Surgery is required to drain and remove them.
  • Bacterial Infection: The prostate can develop an infection like any part of the body and this can cause it to become inflamed and increase in size. In severe cases, an abscess may even form. Infections of the prostate are treated with long courses of antibiotics.
  • Cancer: Prostate cancer in dogs is very rare, but it is also very difficult to treat. Neutering may be an option if the cancer is associated with the testicles and radiotherapy can be tried, but the prognosis for a dog with prostate cancer is not good.
Dogs may pick up a toxic substance that causes them to pass blood.

Dogs may pick up a toxic substance that causes them to pass blood.

Other Causes of Blood in Urine

Blood in the urine can be a consequence of physical trauma, such as a severe fall or being hit by a car. In this case, an underlying disease is not the issue, and you may know at once what is the likely cause of the blood. Of course, you should still seek veterinary advice, even if your dog seems fine, as there could be damage internally you cannot see.

Poisoning is another possible cause of blood in the urine. Certain toxic substances will cause bleeding internally, there are usually other signs of a problem in this instance, such as vomiting, weakness, and difficulty breathing. Poisoning must be treated by a vet immediately.

Cancer in the urinary system (bladder, kidneys, prostate, etc) can lead to blood in the urine. Such cancers are not common in dogs, but in older animals where other causes have been ruled out, they can be a possibility. There will usually be other indications of cancer, such as lethargy, loss of weight, possibly accompanied by loss of appetite, lumps, and bumps, or the dog seeming generally unwell.

Fortunately, most cases of blood in the urine are due to treatable conditions and your dog will be fine once they have received veterinary care. But blood in the urine is a warning sign and you should not ignore it, even if you only notice it once. Your vet will be able to perform simple tests to discover the cause, and treatment is generally straightforward. Leaving the problem will lead to it getting worse and your dog suffering, so never ignore the signs when you see them.

This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.

© 2021 Sophie Jackson