Von Willebrand Disease
von Willebrand disease
Also known as: vWD, von Willebrand syndrome, vWS
von Willebrand disease
Also known as: vWD, von Willebrand syndrome, vWS
In short
Von Willebrand disease is the most common inherited bleeding disorder in dogs, caused by a deficiency or dysfunction of a crucial clotting protein called von Willebrand factor. While many affected pets show no spontaneous signs, they face a high risk of life-threatening bleeding during surgery, injury, or teething. Learn how vets diagnose, treat, and manage this genetic condition.

TL;DR. Von Willebrand disease is an inherited bleeding disorder that impairs a pet's ability to form blood clots, making them highly vulnerable to excessive bleeding during surgery, injury, or teething.

Doberman Pinschers are genetically predisposed to von Willebrand disease.
To understand von Willebrand disease (vWD), it helps to understand how a healthy body stops bleeding. When a blood vessel is damaged, the body initiates a complex process called hemostasis. The very first step, known as primary hemostasis, involves platelets, which are tiny, specialized cell fragments circulating in the blood. These platelets must quickly rush to the injury site, stick to the damaged vessel wall, and clump together to form a temporary plug.
However, platelets cannot stick to the blood vessel wall on their own. They require a specific molecular glue to bind them to the exposed tissue. This molecular glue is a large protein called von Willebrand factor (vWF). In pets with von Willebrand disease, this crucial protein is either deficient or structurally abnormal. As a leading veterinary internal medicine reference explains:
"The vWF molecule circulates coiled; it uncoils at the site of endothelial damage, binds to the subendothelium and then to the platelet receptors, and the platelets are reeled in to the site of injury. As a consequence, vWD is usually characterized by primary hemostatic defects (e. g. , petechiae, ecchymoses, mucosal bleeding). However, most dogs with vWD do not bleed spontaneously but bleed excess"
— Veterinary Internal Medicine, p. 1289
Without functional vWF, the platelets cannot be reeled in effectively. The temporary plug fails to form, leading to prolonged, uncontrolled bleeding. Veterinary medicine classifies vWD into three distinct types based on the nature of the protein deficiency:
While vWD is widely recognized as the most common inherited bleeding disorder in dogs, it can occasionally affect cats. Because feline cases are exceedingly rare, much of the diagnostic and treatment guidance for cats is extrapolated from established canine protocols.
Von Willebrand disease is an inherited genetic condition. It is caused by mutations in the gene responsible for producing the von Willebrand factor protein. Because it is a congenital defect, pets are born with the condition, and it persists throughout their entire lives.
The mode of inheritance varies depending on the breed and the specific type of vWD. In many common breeds, the disease is inherited as an autosomal dominant trait with incomplete penetrance. Incomplete penetrance means that not every dog carrying the mutated gene will show the same severity of symptoms. Some may have very low vWF levels and bleed severely, while others with the same mutation may have near-normal clotting ability. In other breeds, the disease is inherited as an autosomal recessive trait, meaning a puppy must inherit two copies of the mutated gene (one from each parent) to be affected. Recessive forms typically result in the more severe Type 2 or Type 3 vWD.
According to a leading veterinary critical care textbook:
"Inheritance is autosomal dominant or recessive in type I but autosomal recessive in types II and III. No sex predilection has been found. Animals with vWD typically show mucosal bleeding..."
— Small Animal Critical Care Medicine, p. 636
Because there is no sex predilection, male and female pets are affected at equal rates.
Many pets with von Willebrand disease show no outward signs of illness. They can run, play, and live for years without their owners ever suspecting a clotting disorder. The first indication of a problem often occurs during a routine surgical procedure, such as a spay, neuter, or dental extraction, where the pet bleeds excessively and fails to form normal clots. When clinical signs do appear, they typically involve bleeding from the body's mucous membranes (mucosal bleeding) rather than deep tissue bleeding or joint swelling.
Common Signs
Occasional Signs
Rare Signs

Bleeding gums during teething can be an early sign of von Willebrand disease.
Diagnosing von Willebrand disease requires a systematic, step-by-step approach. Because the symptoms of vWD mimic other bleeding disorders, your vet must rule out other potential causes before confirming a diagnosis. The diagnostic process typically begins with a physical examination and a review of your pet's breed and family history. If your vet suspects a bleeding disorder, they will recommend the following tests:
Platelet Count: This is always the first step. Your vet must rule out thrombocytopenia (a low number of platelets) before investigating functional platelet defects. As a leading critical care reference notes:
"The typical physical examination finding in a known breed affected with vWD leads the clinician to measure a manual and automated platelet count. Thrombocytopenia must be ruled out before continuation through the ensuing coagulation work-up."
— Small Animal Critical Care Medicine, p. 637
If the platelet count is normal, but the pet is still bleeding excessively, the vet will proceed to functional testing.
Buccal Mucosal Bleeding Time (BMBT): This is a practical, in-clinic test that measures how well your pet's platelets and vWF work together to form a clot in real-time. Your vet will gently elevate your dog's upper lip and make a tiny, standardized incision on the inner surface of the lip using a spring-loaded device. They will then time how long it takes for the bleeding to stop completely. While a prolonged BMBT indicates a primary clotting defect, it is not specific to vWD alone, and a normal result does not completely rule out the disease.
PFA-100 Test: This is an advanced, automated screening tool used preoperatively in high-risk breeds. The PFA-100 system simulates high-shear blood flow through a microscopic aperture, measuring the time it takes for a platelet plug to block the opening. This test is highly sensitive for detecting platelet dysfunction and vWD prior to surgery.
vWF:Antigen Concentration Measurement (vWF:Ag): This is the gold standard test for confirming von Willebrand disease. A blood sample is collected and sent to a specialized veterinary coagulation laboratory. The lab measures the exact concentration of von Willebrand factor antigen in the plasma. Results are reported as a percentage compared to a pool of normal canine plasma. A level under 50% is diagnostic for von Willebrand disease, and pets with levels below 35% are at high risk for clinical bleeding.
Genetic Testing: DNA tests are available for several specific breeds. These tests can identify whether a dog is clear, a carrier, or affected by the specific genetic mutation responsible for vWD in their breed. Genetic testing is highly recommended for breeding dogs and can be performed at any age, even in young puppies.

Specialized laboratory tests are required to measure von Willebrand factor levels.
There is no permanent cure for von Willebrand disease, as the genetic defect cannot be corrected. However, the condition can be managed highly effectively, particularly when planning for surgical procedures or managing acute bleeding episodes.
Desmopressin is a synthetic hormonal agent and a vasopressin analogue. It is the primary medical treatment used to manage Type 1 vWD. When administered (typically via an injection under the skin or intranasally), desmopressin stimulates the cells lining the blood vessels (endothelial cells) to release their stored reserves of von Willebrand factor into the bloodstream. This temporary boost in circulating vWF levels improves clotting function for several hours. Your vet will often administer desmopressin approximately 30 minutes before a scheduled surgery to minimize the risk of excessive bleeding. It is important to note that desmopressin is only effective in pets that have stored reserves of vWF (primarily Type 1). It is generally ineffective for pets with Type 2 or Type 3 vWD, as they lack functional reserves of the protein.
For pets with severe forms of the disease (Type 2 or Type 3), or for any vWD-affected pet experiencing an active, life-threatening hemorrhage, transfusion therapy is the treatment of choice.
Managing a pet with vWD requires strict avoidance of medications that can impair platelet function. You must never give your pet aspirin, non-steroidal anti-inflammatory drugs (NSAIDs) like carprofen or meloxicam, or certain antibiotics (such as high-dose penicillins) unless specifically instructed by your vet. These medications can further compromise your pet's already weakened clotting system, triggering severe bleeding.
The long-term outlook for a pet with von Willebrand disease depends heavily on the specific genetic type they carry and how well the condition is managed.
Because von Willebrand disease is an inherited genetic disorder, it cannot be prevented through lifestyle changes, vaccines, or diet. The only way to prevent the disease is through responsible breeding practices.
If you own a breed predisposed to von Willebrand disease, or if your pet has been diagnosed with the condition, you must monitor them closely for any signs of bleeding. Contact your veterinarian if you notice:
Emergency Red Flags
Seek immediate emergency veterinary care if your pet exhibits any of the following signs of severe internal bleeding or acute blood loss:
Von Willebrand disease has been documented in over 50 breeds of dogs, but certain breeds carry a significantly higher genetic risk. The mode of inheritance and severity of the disease vary by breed:
Treatment must be prescribed by a licensed veterinarian based on your pet. Specific drug doses are intentionally not shown here.
Von Willebrand disease is the most common inherited bleeding disorder in dogs, caused by a deficiency or dysfunction of a crucial clotting protein called von Willebrand factor. While many affected pets show no spontaneous signs, they face a high risk of life-threatening bleeding during surgery, injury, or teething. Learn how vets diagnose, treat, and manage this genetic condition.
Excessive bleeding during or after surgery、Mucosal bleeding、Perinatal death, abortions, or stillbirths、Diffuse oropharyngeal or vaginal bleeding、Epistaxis、Excessive bleeding during teething or estrus、Excessive cavity bleeding after surgery、Gingival hemorrhage
vWF:antigen concentration measurement、Buccal mucosal bleeding time (BMBT)、PFA-100 test、Platelet count、genetic testing
Treatment must be prescribed by a licensed veterinarian based on your pet. Specific drug doses are intentionally not shown here.
This article is for general education and is not a substitute for professional veterinary advice. If your pet is unwell, please consult a veterinarian.
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