Hematomas in Dogs
When a dog becomes injured they can occasionally rupture some blood vessels causing minor internal bleeding. Blood collected in a pocket inside the body it is called a hematoma. While hematomas can occur in any part of the dog’s body, most develop just under the skin because that is the area most likely to incur injury. A hematoma looks like a swollen lump under the skin.
Most hematomas are caused by trauma, but some dogs may develop them due to a clotting disorder. Hematomas on organs or in the brain can lead to more serious medical conditions, but most subdermal hematomas are not serious. Your veterinarian can assess how serious the hematoma is and determine if treatment is needed. Some smaller hematomas will go away on their own, while larger ones may need to be drained.
The most common place for a hematoma on a dog is their ears. Ears have lots of blood vessels, so when wounded they bleed profusely. Due to the closed shape of ear flaps, it is an area that is easy for fluid (blood) to accumulate because it has no place to go. If a dog’s ear is itchy they often will scratch at their ears and shake their head in discomfort, which can rupture a blood vessel and cause the ear flap to fill with blood. If the ear feels, swollen, warm and soft to the touch your dog probably has an ear hematoma. Your vet can drain the blood out and the ear will usually require a few stitches to prevent it from filling up until it is healed.
Studies
Spontaneous aortic dissecting hematoma in two dogs.
Traumatic intracerebral hematoma in a dog: MR images and clinical findings.
Thymic hematoma in juvenile dogs associated with anticoagulant rodenticide toxicosis.
Experimental study on the evolution of chronic subdural hematoma.