Aural hematomas are warm, painful swellings under the skin of a dog’s ear flap from accumulation of blood. They are common, and usually happen when dogs shake their heads and scratch at their ears to relieve itching associated with ear infections. Other things that can lead to head-shaking and ear-scratching are skin allergies, food allergies, infestation by fleas, mites, ticks or lice and twigs, grass awns, foxtails or other foreign things getting stuck inside the ear. Puncture wounds from fights with other animals can also cause hematomas. Dogs with long, heavy ears are most likely to develop aural hematomas, as are those living in hot, humid climates and those that go swimming a lot. Diagnosis isn’t difficult and surgical treatment fortunately is usually successful.