Aural Hematoma

An aural hematoma is one of the more startling things an owner can discover: seemingly overnight, a cat's normally thin, flexible ear flap balloons into a thick, fluid-filled cushion. Despite its dramatic appearance, the underlying mechanism is simple. The ear flap (pinna) is a sandwich of skin over a thin sheet of cartilage, supplied by delicate blood vessels. When a cat shakes its head violently or scratches repeatedly at its ear, the shearing forces can rupture one of these vessels. Blood then leaks out and pools in the space between skin and cartilage, creating the characteristic soft, warm, sometimes squishy swelling.

The crucial point — and the part owners often miss — is that the hematoma is a consequence, not the root problem. A cat does not shake and scratch at a healthy, comfortable ear. Almost always there is an underlying irritation driving the behaviour: ear mites (especially common in younger cats and a frequent culprit), a bacterial or yeast infection, allergic skin disease, or occasionally a grass seed or other foreign body in the ear canal. Treating the swelling without addressing this cause simply invites the hematoma to return.

Left untreated, a hematoma will eventually be reabsorbed by the body, but rarely in a tidy way. As the blood clot organises and contracts, it pulls and scars the ear into a shrivelled, thickened shape — the so-called 'cauliflower ear' — which, while largely cosmetic, can also narrow the ear canal. For this reason vets usually recommend active treatment. Options range from simple needle drainage (quick but prone to refilling) to placement of a small drain, up to surgery in which the fluid is removed and rows of sutures are placed through the ear to press the skin and cartilage back together while they heal. Whichever route is chosen, simultaneously diagnosing and treating the underlying ear disease is what ultimately resolves the problem and stops it coming back.