High blood pressure in dogs is almost always caused by an underlying disease rather than being a condition on its own. Unlike humans, where high blood pressure often develops independently, dogs predominantly suffer from what veterinarians call secondary hypertension, meaning another health problem is driving the blood pressure up. The most common culprits are kidney disease, hormonal disorders, and adrenal gland tumors.
Why Dogs Rarely Get “Simple” High Blood Pressure
In humans, high blood pressure frequently appears without a clear cause. Doctors call this primary or essential hypertension, and it accounts for most human cases. In dogs, the situation is reversed. Primary hypertension is rare, and when a dog is diagnosed with elevated blood pressure, the veterinarian’s first job is to figure out what disease is behind it. This distinction matters because treating the underlying condition is often the most effective way to bring blood pressure back down.
Kidney Disease Is the Leading Cause
The kidneys are the body’s main blood pressure regulators, so any damage to their structure can throw that system off. When kidney tissue is scarred or inflamed, the organs respond by activating a hormonal chain reaction that narrows blood vessels and causes the body to retain salt and water. Both of those effects push blood pressure higher.
The numbers are striking. Roughly 60% of dogs with general kidney disease develop high blood pressure, and that figure climbs to about 80% in dogs whose kidneys have a specific type of damage called glomerular disease, which affects the kidney’s filtering units. This makes chronic kidney disease the single most common driver of canine hypertension. The relationship also runs in both directions: high blood pressure damages the kidneys further, creating a cycle that accelerates decline if left untreated.
Cushing’s Disease and Other Hormonal Disorders
Cushing’s disease, where the body produces too much cortisol, is another major cause. The excess cortisol affects blood vessel tone, fluid balance, and how the body handles salt, all of which raise blood pressure. Research shows that 86% of dogs with untreated Cushing’s disease are hypertensive. Even after treatment begins, about 40% remain hypertensive, which means blood pressure monitoring stays important long after diagnosis.
Certain breeds face higher Cushing’s risk, including Dachshunds, Poodles, and several terrier breeds. Diabetes is another hormonal condition linked to hypertension, and breeds like Australian Terriers, Schnauzers, Bichons Frises, and Spitz dogs carry increased diabetes risk. Thyroid disorders, though less commonly discussed in dogs than in cats, can also contribute.
Adrenal Gland Tumors
A less common but serious cause is a tumor called a pheochromocytoma, which grows in the inner part of the adrenal gland. These tumors produce surges of adrenaline and related hormones, causing episodes of rapid heart rate, heavy breathing, and sudden spikes in blood pressure. The symptoms can appear sporadically because the tumor releases these hormones in unpredictable bursts rather than constantly. Surgical removal is the primary treatment, though the procedure carries elevated risk precisely because of the cardiovascular effects these hormones create.
Does Diet Play a Role?
Many dog owners wonder whether too much salt in their pet’s food could cause high blood pressure, since that’s a well-known concern in human health. The evidence in dogs tells a different story. In controlled studies, healthy dogs with normal kidney function fed high-sodium diets showed no significant change in blood pressure, as long as they had free access to water. Salt doesn’t appear to independently cause hypertension in otherwise healthy dogs.
That said, once a dog has kidney disease or another condition driving high blood pressure, dietary sodium becomes more relevant. Damaged kidneys can’t handle excess salt efficiently, so veterinarians often recommend lower-sodium diets as part of managing the overall condition. The key distinction is that salt is a management concern in sick dogs, not a cause in healthy ones.
How Veterinarians Define High Blood Pressure
Dogs are classified into risk categories based on systolic blood pressure, the higher number in a reading. Normal is below 140 mmHg. Between 140 and 159 is considered prehypertensive, with low risk of organ damage. Readings of 160 to 179 fall into the hypertensive range with moderate risk. At 180 or above, a dog is severely hypertensive and at high risk for damage to vital organs.
One breed-specific note worth knowing: sighthounds, particularly Deerhounds, naturally run higher blood pressure than other breeds. A reading that would be concerning in a Labrador might be normal for a Greyhound. Your veterinarian should factor breed into the interpretation.
Signs That Blood Pressure Is Causing Damage
High blood pressure in dogs is often called a “silent” problem because it rarely causes obvious symptoms until it has already damaged organs. The eyes, kidneys, heart, and brain are the most vulnerable targets.
Eye damage is the most commonly detected consequence. High pressure can cause bleeding or swelling in the back of the eye, and in severe cases, the retina detaches, leading to sudden blindness. Some owners first discover their dog’s hypertension only when the dog starts bumping into furniture or seems disoriented in familiar spaces.
The heart has to pump against higher resistance when blood pressure stays elevated, which over time causes the heart walls to thicken. A veterinarian may detect a new heart murmur during a routine exam. Neurological signs, including disorientation, loss of balance, seizures, or behavioral changes, occur in a significant minority of hypertensive animals and reflect damage to blood vessels in the brain. Meanwhile, the kidneys suffer increased protein loss, which accelerates any existing kidney disease.
How High Blood Pressure Is Managed
Because canine hypertension is usually secondary, the first priority is treating whatever disease is driving it. Controlling Cushing’s disease, managing kidney failure, or removing an adrenal tumor can sometimes resolve the blood pressure problem on its own, or at least reduce it significantly.
When blood pressure remains elevated despite treating the underlying cause, or when the pressure is high enough to risk organ damage, veterinarians prescribe blood pressure medications. The most commonly used options work by either relaxing blood vessel walls to reduce resistance or by blocking the hormonal pathways that cause the body to retain fluid and constrict vessels. Dogs typically take these medications once or twice daily, and blood pressure is rechecked periodically to adjust the dose.
Monitoring is an ongoing commitment. Dogs on blood pressure medication need regular veterinary visits to ensure the pressure stays in a safe range and to watch for progression of whatever underlying disease triggered the problem in the first place.