It’s likely that your dog will need medical care for a health condition at least once in its life—especially if it’s a breed that’s predisposed to health issues like pugs. One health issue that’s common in dogs is an ear hematoma, often referred to as a blood blister. Thankfully, there’s an effective surgery that can resolve it.

When a pup’s ear is irritated—either by an ear infection, allergy or something else—it will usually shake its head. Sometimes this violent motion causes the blood vessels in a dog’s ear flap to break, leading to internal bleeding. This blood accumulation in the dog’s ear flap is known as an ear hematoma.

An ear hematoma is primarily the result of underlying ear conditions such as an ear infection, allergies, a wound, a blood-clotting disorder or something else.

“Ear hematoma can be associated with allergies and ear infections or just from trauma…[which can result from] dogs running around or [bumping] into something,” explains Dr. Boaz Man, D.V.M., medical director and owner of Boca Midtowne Animal Hospital in Boca Raton, Florida.

Man says dogs with long floppy ears and those prone to ear infections are more likely to get ear hematoma. Dogs with cocked ears are also more predisposed. According to a 2021 study in Scientific Reports, the breeds most likely to develop the condition are bull terriers, Saint Bernards and French bulldogs.