What Does Blood in a Dog's Urine Mean?

Is Blood in Your Dog's Urine a Reason for Concern?

Discovering a red stain when your dog urinates or after they get up from resting can be alarming. It's natural to feel anxious whenever blood appears, as it might point to something as minor as a urinary tract infection or as serious as cancer. Being aware of blood in urine is important because it often signals an underlying problem.

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

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Could Your Female Dog Be in Heat Instead?

If your female dog hasn't been spayed, blood spots on surfaces she's sat on might not mean a urinary infection—it could be her season, also known as being in heat. For young dogs, this might be their first season, and the blood can surprise owners. How can you tell a UTI from a season? Blood from a season comes from the reproductive tract, not the urinary tract, so you're less likely to see it mixed with urine; instead, you'll notice spots where she's been lying. Other signs of a season include a swollen vulva, interest in or from male dogs, swollen nipples, and behavior shifts like clinginess, sleepiness, or anxiety. Seasons typically last about three weeks, with bleeding usually in the first week, stopping by the second, and possibly returning in the third. If symptoms persist or you're unsure, consult your vet.

UTIs are common in older dogs, especially female dogs.

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Urinary Tract Infections: The Most Frequent Reason for Blood in Urine

In both male and female dogs, blood in urine often signals a urinary tract infection (UTI). This means an infection has taken hold somewhere in the urinary system—bladder, kidneys, prostate (in males), or the tubes that carry urine out. Other UTI signs include pain while urinating, incontinence, licking the genital area, tiredness, poor appetite, weight loss, and fever. Some UTIs cause odd behaviors that can be mistaken for dementia in older dogs, such as barking at shadows, staring at walls, or acting restless. Older dogs, especially females, are more prone to UTIs, and dogs with diabetes face a much higher risk. UTIs don't clear up on their own; they need antibiotics from a vet. Sometimes one course isn't enough, and different antibiotics may be required.

Bladder or Kidney stones can cause a lot of discomfort.

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Stones in the Kidneys or Bladder

If there's no infection, blood in urine could be from stones—hard mineral formations in the kidneys or bladder. They can be tiny and numerous (like gravel) or one large stone. These stones hinder urine flow and scrape against organ walls, causing bleeding. This condition is considered very painful and can be life-threatening if a large stone blocks the tubes to the kidneys or bladder, stopping urine from passing. A UTI might also develop because of the stones, making diagnosis harder. Treatment options include surgery (not always suitable for dogs with other health issues), flushing out small stones with a special tool under sedation, or a special diet to dissolve stones—though this depends on the stone type, is slow, and doesn't always succeed. If a stone blocks urine flow, emergency surgery is the only way to save the dog's life.

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

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Prostate Issues

Unneutered male dogs can develop prostate problems. The prostate is a small gland near the bladder neck. In intact dogs, it can enlarge, causing trouble urinating and sometimes pooping. Several conditions can cause this, and most are treatable. Benign Prostatic Hyperplasia (BPH) is the most common, driven by testosterone, and can be cured by neutering or managed with medication if neutering isn't advisable. Squamous metaplasia is similar but caused by estrogen, often linked to a testicular tumor; neutering to remove the tumor resolves it. Paraprostatic cysts are usually present from birth and cause issues later; surgery is needed to drain and remove them. Bacterial infection can inflame the prostate and cause swelling; in severe cases, an abscess may form, and long antibiotic courses are used. Prostate cancer is rare in dogs but hard to treat; neutering may help if linked to testicles, and radiotherapy can be tried, but the outlook is poor.

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

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Additional Causes of Blood in Urine

Physical trauma, like a bad fall or being hit by a car, can lead to blood in urine. In such cases, you might know the cause, but still seek vet advice even if your dog seems fine, as internal damage may be hidden. Poisoning is another cause; certain toxins cause internal bleeding, usually with other signs like vomiting, weakness, and breathing trouble. Immediate vet care is essential for poisoning. Cancer in the urinary system (bladder, kidneys, prostate, etc.) can cause blood in urine. These cancers are uncommon in dogs, but in older dogs where other causes are ruled out, they're possible. Other cancer signs often include lethargy, weight loss, sometimes loss of appetite, lumps, or general unwellness. Most cases of blood in urine are due to treatable conditions, and dogs recover with vet care. But it's a warning sign—don't ignore it, even if it happens once. Your vet can run simple tests to find the cause, and treatment is usually straightforward. Leaving it can worsen the problem and cause suffering, so always act when you notice it.

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