An aural hematoma is a swelling of the ear flap (pinna) filled with blood-tinged fluid. It forms when tiny blood vessels inside the ear flap break and fluid leaks into the space there [2]. Dogs get them more often than cats, and dogs with floppy ears are more at risk, but cats can get them too [2]. In dogs it is the injury of the ear flap that vets see most often [3].
If your pet’s ear flap is suddenly puffy or swollen, see your vet. A hematoma usually points to another problem, such as an ear infection, that needs treatment as well [2].
Do not try to drain or pop the swelling at home.
Signs of an aural hematoma
- A swollen ear flap: part or all of the flap puffs up with fluid [2][6].
- A soft feel: the swelling is a pocket of fluid, so it usually feels soft and squashy rather than hard [2].
- Pain and discomfort: the swelling, the inflammation and the extra weight of the flap can make the ear sore [2]. Your pet may shake its head or scratch at the ear.
Why it happens
A small blood vessel in the ear flap breaks, and fluid builds up inside the flap [2].
The vessel usually breaks because of something else. Vets have long linked hematomas to heavy head shaking [1]. Ear infections (otitis), ear parasites such as mites, and immune problems are among the main causes listed, along with plain excessive ear shaking [2]. Otitis externa means inflammation or infection of the outer ear canal.
- Dogs: a very large study of dog health records in England, summarised by Harvey, found the risk went up with age and body weight, and was higher in some breeds, such as Golden Retrievers, St Bernards, French Bulldogs and English and Staffordshire Bull Terriers [1]. Dogs with folded or half-upright ears were also more at risk [1].
- Cats: cats can get hematomas too, often for the same reasons, so your vet will look for an ear infection or mites [2].
The exact way the swelling forms is still not fully known [2]. One idea is that the ear cartilage loses some of its stretch with age, and repeated bending at the fold of the flap, for example in a dog with an itchy ear, may crack it [1]. In one study of 10 dogs, the fluid looked more like clear tissue fluid than blood, and it sat in a split within the cartilage [5].
For the common causes of ear itching, see ear infections in dogs and cat ear mites and ear problems.
Other causes of a swollen ear flap
Not every swelling is a hematoma. In one white cat, a lump that looked like a hematoma turned out to be a cancer of the blood vessels (hemangiosarcoma). The authors suggest vets keep this cancer in mind when a white cat has an ear swelling that looks unusual [4]. Your vet can check what the swelling is. For more on this cancer, see skin hemangioma and hemangiosarcoma in dogs and cats.
How vets treat an aural hematoma
Treatment has two parts: the swelling and the cause.
The cause. Finding and treating what started the problem, such as an ear infection, is key to success [2].
The swelling. Vets have several options [2][3]:
- draining the fluid, sometimes together with medicine injected into the ear flap [2];
- surgery under sedation or anesthesia, which opens and drains the swelling and uses stitches to hold the skin against the cartilage while it heals [1][2];
- other methods, such as a drain that gently draws fluid out over time [5] or a splint stitched onto the ear flap [6];
- medicine alone, without surgery, which some vets now use more often [3].
A bandage may be part of the care [2]. Your vet chooses the method that suits your pet and can explain the choices.
At home, as directed by a vet:
- give all medicines exactly as prescribed, including any ear medicine;
- keep any bandage clean and dry, and do not remove it unless your vet tells you to;
- stop your pet from scratching or shaking at the ear in the way your vet advises;
- do not drain, press or pop the swelling;
- go back for every recheck, including stitch removal.
Outlook
Outcomes vary between studies:
- A long-standing hematoma can turn into scar tissue inside the flap. This can leave the ear thickened and badly misshapen (“cauliflower ear”) and may make later ear infections more likely [2].
- Surgery does not always go smoothly. Reported problems include slow healing, infection, thickening and wrinkling of the ear flap, and the swelling can come back [2].
- In 10 dogs treated with a drain, 9 had no return of the swelling 6 months after surgery. One dog’s ear got infected and ended up wrinkled [5].
- Among 7 dogs and 3 cats given a splint, 8 of the 10 ears healed after the first treatment. In 2 dogs the swelling came back, probably because the splint came off too early, and healed after a second splint. One dog was left with a small wrinkled area [6].
- In 24 dogs given medicine by mouth instead of surgery, 21 improved a lot, but this study had no comparison group [3].
These are figures and statements about groups of animals in particular studies. They do not prove that a treatment caused an outcome, and they cannot predict how one pet will do. Your vet can explain what this means for your pet.
When to see your vet
See your vet if your dog or cat has:
- a puffy, soft or swollen ear flap [2];
- an ear flap that is sore to touch [2];
- a lot of head shaking or ear scratching [1][2];
- discharge, smell or redness in the ear canal.
See your vet again if the swelling comes back, the ear looks red or hot, or a bandage gets wet, dirty or slips.
FAQ
What does an aural hematoma feel like?
Usually soft and puffy, because it is a pocket of fluid inside the ear flap [2].
Can I drain my dog’s ear hematoma at home?
No. Do not drain, press or pop it. See your vet, who will also look for the cause of the head shaking or scratching [2].
Will it go away on its own?
Do not wait to find out. A hematoma left for a long time can scar and leave the ear misshapen [2]. Your vet can explain the choices.
Will my pet’s ear look normal again?
It varies, and no one can promise it. Wrinkling or thickening can happen even with treatment [2][5][6]. See the Outlook section above.
Can it come back?
It can [2][6]. Treating the cause of the scratching or head shaking is key [2]. See the Outlook section above.
The bottom line
An aural hematoma is a pocket of blood-tinged fluid in the ear flap, most often linked to head shaking or scratching because of an itchy or infected ear. It is more common in dogs than cats. The ear feels soft and puffy. Do not drain it at home. Your vet treats both the swelling and the cause, often with surgery, and the ear may still end up scarred or crinkled.
This article is for general information only and does not replace advice from your veterinarian. If your pet’s ear flap is swollen, see your vet.
Sources
- Harvey R. A Review of Recent Developments in Veterinary Otology. Vet Sci. 2022;9(4):161. CC BY 4.0. https://pmc.ncbi.nlm.nih.gov/articles/PMC9032795/
- Palagiano P, Graziano L, Scarabello W, Berni P, Andreoli V, Grolli S. Platelet-Rich Plasma Treatment Supported by Ultrasound Detection of Septa in Recurrent Canine Aural Hematoma: A Case Series. Animals (Basel). 2023;13(15):2456. CC BY 4.0. https://pmc.ncbi.nlm.nih.gov/articles/PMC10417061/
- Rüfenacht S, Schellenberg S, Borio S, Summerfield A, Ricklin ME. Non-blinded treatment of aural hematoma with oral prednisolone as a monotherapy in privately-owned dogs. Schweiz Arch Tierheilkd. 2022;164(6):447-455. https://pubmed.ncbi.nlm.nih.gov/35652255/
- Borges OMM, Noronha de Toledo G, Carneiro RS, et al. Aural Hematoma Secondary to Hemangiosarcoma in a Domestic Cat: Case Report. Top Companion Anim Med. 2020;41:100462. https://pubmed.ncbi.nlm.nih.gov/32823161/
- Lahiani J, Niebauer GW. On the nature of canine aural haematoma and its treatment with continuous vacuum drainage. J Small Anim Pract. 2020;61(3):195-201. https://pubmed.ncbi.nlm.nih.gov/31975442/
- Xie Y, Deng Y, Teng X, et al. Successful surgical management of aural hematoma with the application of polycaprolactone splint in 7 dogs and 3 cats. J Am Vet Med Assoc. 2025;263(5):1-6. https://pubmed.ncbi.nlm.nih.gov/39892399/