Protein in dog urine, or proteinuria, can signal a range of health issues in dogs. While small amounts of protein in urine may be harmless, persistent or high levels often point to underlying conditions like chronic kidney disease, infections, or elevated blood pressure called systemic hypertension. This article will explore the causes, diagnosis, and treatment options for proteinuria, helping you understand what steps to take.
What is proteinuria in dogs?
The term proteinuria means protein in the urine.
Just like humans, dogs need healthy kidneys. Kidneys act like filters, removing waste products from the blood and creating urine. This process keeps the body clean and balanced.
Normally, these amazing filters keep protein in the blood where it belongs. Protein is important for building and repairing tissues, fighting off infections, and many other vital jobs. But sometimes, the kidneys don't work perfectly, and protein can leak into the urine.
There are a few types of proteinuria:
- Functional renal proteinuria: This is temporary and can result from factors like stress, fever, or intense exercise. It typically resolves without treatment.
- Pathologic renal proteinuria: This occurs when the kidneys are unable to filter properly, often due to conditions like glomerular disease, kidney disease, or damage to the glomerular filtration barrier.
If untreated, pathologic proteinuria may lead to serious kidney disease or other complications as we will discuss below.
Causes of protein in dog urine
Many things can cause proteinuria in dogs. Sometimes it's a temporary issue, but it can also be a sign of an underlying disease. Here are some of the most common causes:
Kidney diseases
- Chronic kidney disease is a common problem, especially in older dogs. It means the kidneys are slowly losing their ability to filter waste and protein properly, which results in renal proteinuria.
- Glomerular disease affects the tiny filters within the kidneys called glomeruli. These filters are important for keeping protein in the blood. Any disruption to the glomerular filtration barrier can cause glomerular proteinuria.
- Kidney failure occurs when the kidneys can no longer function properly, leading to a buildup of toxins and protein loss in the urine.
- Nephrotic syndrome results in severe proteinuria in dogs which is called protein-losing nephropathy.
- Immune-mediated glomerulonephritis is a kidney condition where the immune system attacks the glomerulus, the filtering part of the kidneys.
- Linked hereditary nephropathy is a genetic condition that can cause kidney disease and proteinuria in certain breeds.
Infections
- Urinary tract infections (UTIs) can cause inflammation in the urinary tract and lead to urine protein.
- Lyme disease, an infectious disease spread by ticks, can also affect the kidneys and cause persistent proteinuria.
- Reproductive tract disease in female dogs can also lead to proteinuria.
- Leptospirosis: This bacterial infection can lead to kidney damage and proteinuria in dogs. It's transmitted through contact with contaminated water or soil.
Other causes
- High blood pressure (systemic hypertension) can damage the kidneys and cause proteinuria.
- Fever can sometimes lead to temporary proteinuria.
- Strenuous exercise can also cause a temporary increase in protein in the urine.
- Diabetes and Cushing's disease can also cause proteinuria in dogs.
- Certain medications such as prednisone for dogs may have proteinuria as a side effect.
It's important to remember that these are just some of the possible underlying causes. If your dog has protein in the urine, your veterinarian will run tests to determine the underlying cause.

What are the symptoms of proteinuria in dogs?
The tricky thing about proteinuria - you often can't see it! Unlike some health problems with obvious signs, protein in the urine usually doesn't cause noticeable changes in your dog's appearance or behavior. This is why regular checkups and urine tests with your vet are so important.
However, sometimes proteinuria comes with other signs that something is wrong. These signs often relate to the underlying cause of proteinuria, such as kidney disease or urinary tract infections.
Here are some things you might notice if your dog has proteinuria:
If you notice any of these symptoms, it is best to see your veterinarian for further advice.
Diagnosing proteinuria in dogs
Diagnosing protein in urine starts with a thorough examination and specific tests to pinpoint the cause. Early detection helps prevent complications like serious kidney disease or even kidney failure.
Here's how we figure out what's going on:
- Urine sample: First, your vet will need a urine sample from your dog. This might involve collecting urine at home or having your vet collect it at the clinic.
- Urinalysis: A urinalysis is a simple test that checks the urine for various things, including protein, blood cells, and signs of infection (lower urinary tract disease).
- Urine culture: A urine culture detects specific bacterial infections in the urinary tract.
- Urine Protein Creatinine Ratio (UPCR): If protein is found in the urine, your vet might recommend a urine protein creatinine ratio test. This helps determine the amount of protein relative to creatinine, another waste product in urine. This creatinine ratio gives a more accurate picture of protein loss.
Depending on the results of the urinalysis and urine protein creatinine ratio, your vet may suggest:
- Blood tests: A complete blood count (CBC) and blood chemistry panel can check for signs of kidney disease, some infections, and other health issues. They can also check serum creatinine and blood urea nitrogen (BUN) levels to assess kidney function.
- Blood pressure measurement: High blood pressure can damage the kidneys, so it's important to check. High systemic blood pressure can result in protein in the urine.
- Imaging: An abdominal ultrasound can help visualize the kidneys and urinary tract to look for abnormalities.
- Kidney biopsy: In some cases, a kidney biopsy may be needed to examine kidney tissue under a microscope and get a definitive diagnosis. This helps identify specific conditions like glomerular disease or immune-mediated glomerulonephritis.
How is proteinuria treated in dogs?
Treatment for protein in the urine of dogs focuses on managing the underlying cause and reducing kidney damage. Addressing this issue early improves outcomes and prevents complications like kidney failure.
The exact treatment will depend on the underlying cause that your veterinarian identifies. Here are some common approaches:
Addressing the underlying cause
- If a urinary tract infection is causing the problem, antibiotics will likely clear it up.
- For kidney disease, treatment focuses on slowing its progression and managing symptoms. This might involve medications to control blood pressure, special diets (diet modulates proteinuria), and supportive care.
- If high blood pressure is a factor, medications like angiotensin-converting enzyme (ACE) inhibitors, such as benazapril, or angiotensin receptor blockers may be prescribed. These help protect the kidneys from further damage. In some cases, other medications may be needed to control systemic blood pressure.
- Immunosuppressive therapy may be necessary for certain conditions like immune-mediated glomerulonephritis.
Medications
Aside from addressing the underlying cause, some medications can help reduce protein loss in the urine. These may include ACE inhibitors and other drugs that help support kidney function and reduce glomerular capillary pressure.
Dietary changes
Your vet might recommend a special diet for your dog to help manage proteinuria. These diets are typically lower in protein and phosphorus, which can help reduce the workload on the kidneys. They may also contain increased amounts of omega-3 fatty acids, which can have anti-inflammatory effects.
Monitoring
This typically involves blood pressure monitoring, regular urine tests, and blood work to check kidney function and serum albumin levels. This helps your vet track your dog's progress and adjust treatment as needed.
What are the complications for dogs with proteinuria?
While many dogs with proteinuria can live comfortably with proper management, it's important to be aware of potential complications. These can vary depending on the underlying cause and severity of the proteinuria.
Progression of kidney disease: If proteinuria is caused by kidney disease, it can sometimes contribute to further decline in kidney function. This is because the protein loss can put extra stress on the renal tubules, the tiny tubes in the kidneys that help filter waste.
Nephrotic syndrome: In some cases, proteinuria can lead to nephrotic syndrome. This is a serious condition characterized by protein loss, low serum albumin levels, and fluid retention. It causes fluid accumulation in large spaces such as the abdomen (ascites) and the chest (pleural effusion).
Blood clots: Dogs with proteinuria, particularly those with nephrotic syndrome, may have an increased risk of developing blood clots. This is because protein loss can affect the blood's ability to clot properly.
Protein in your dog’s urine is not something to ignore. While it may sometimes be harmless, persistent proteinuria often points to more serious health conditions. Early detection through tests like a routine urinalysis or urine protein creatinine ratio allows for quick treatment and better outcomes. By addressing the underlying cause, you can protect your dog's kidney function and overall health.