Hemophilia A in Dogs

Category: Blood
Inheritance: X-linked recessive
Breeds documented: 2
Published sources: 6

Overview

A shortage of factor VIII, a protein needed for blood to clot, causes this inherited bleeding disorder. Bleeding can occur after an injury or surgery, and more severely affected dogs may bleed without an obvious injury. Blood may collect under the skin, inside muscles or in joints, causing swelling or a limp. The severity varies between dogs with different forms of the disorder.

Signs to watch for

Bleeding gums during teething
Unusually prolonged bleeding after an injury or surgery
Soft swellings under the skin
Limping with a swollen joint

Signs can begin in puppies, including during teething, but severity varies.

Emergency Go to an emergency vet now if your dog is bleeding heavily.

Diagnosis and tests

Vets use a blood clotting test called aPTT to look for a clotting defect. They confirm hemophilia A by measuring factor VIII activity in a specially prepared blood sample. Blood tests may not reliably separate female carriers from unaffected females, so family history can also be important.

Breeds with documented risk

2 breeds

By breed size

1 Medium
1 Large

German ShepherdLarge · Herding Group
Standard SchnauzerMedium · Working Group

Inheritance

X-linked recessive
The variant sits on the X chromosome. Males have one X, so one copy is enough to affect them. Females have two, so they are usually healthy carriers. Most affected dogs are male, and a carrier mother passes the variant to about half of her sons.
As stated by OMIA

We've gathered what published sources say about this condition, so you can talk it through with your vet. It isn't veterinary advice: you and your vet know your dog best.