Hematomas in dogs

Written by Dr Andrew Miller MRCVSDr Andrew Miller MRCVS is an expert veterinary working in the field for over 10 years after graduating from Bristol University. Andy fact checks and writes for Pure Pet Food while also working as a full time veterinarian. Pure Pet FoodPure Pet Food are the experts in healthy dog food and healthy dogs featured in media outlets such as BBC, Good Housekeeping and The Telegraph. Working with high profile veterinary professionals and nutritionists, Pure Pet Food are changing dog food for the better. - Our editorial process

Although the name might sound a little scary, hematomas are minor and are essentially just what we humans would refer to as a blood blister. Typically forming in the ears, which are referred to as aural or ear hematomas, they’ll cause your dog to experience quite a lot of discomfort.

Hematomas are nothing severe, so don’t worry too much if you spot one, however they do require medical assistance to get rid of.

Keep reading to find out more about what hematomas in dogs are, how they happen, what they look like and how to treat them.

What are hematomas in dogs?

Think of a hematoma as a really bad bruise, they happen when the blood vessels burst from some kind of trauma, causing the blood to pool and accumulate under the skin. This is what forms the blood blister.

You’ll most commonly see a hematoma forming in the flap of your dog’s ear, which is more formally referred to as the pinna of the ear. They usually form here because the vessels in the canine ear are quite delicate, bursting easily. Usually, only one ear will be impacted by a hematoma, but it’s not unheard of for them to occur in both ears at the same time.

What causes hematomas in dogs?

Hematomas normally form following some kind of trauma, most frequently, trauma to the ear. Excessive scratching and head shaking causes these ear injuries. Ear mites and ear infections, such as otitis, are some of the most commonly reported triggers for a hematoma, with a study reporting that 76% of dogs in their study developed an aural hematoma following a case of otitis.

Both mites and infections cause irritation and discomfort, prompting your dog to repeatedly scratch and shake their head to get rid of the itch. When your dog excessively shakes, their ears will slap against their head, which in turn causes the blood vessels to burst. Pooches with the long, floppy ears are therefore the most prone to hematomas, think Cocker Spaniels and Basset Hounds.

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Sometimes, a foreign object could be trapped in your dog’s ear, like a tick or a blade of grass, so your dog has shaken their head in response and the object has fallen out. If so, it might appear like the hematoma has come from nowhere as the source of the scratching has been removed.

Medical conditions, skin irritation and allergies can also be at the root of your dog’s itching, leading to trauma and blood blisters.

Hematomas can occur anywhere, even sometimes forming on the internal organs, however this is quite rare compared to ear hematomas. Male dogs can also form scrotal hematomas, usually following neutering.

What are the signs and symptoms of hematomas in dogs?

The signs and symptoms of hematomas can vary depending on where the blood blister is located, but when it’s located under the skin, somewhere like the ear, they’re pretty easy to spot. Mostly, you’ll notice the swelling, but look out for other symptoms such as:

  • Discolouration

  • Painful to touch

  • The skin feeling hot to touch

  • The hematoma will feel firm

  • Whining and signs of pain

  • Scratching

  • Head shaking

  • If ears were stood up, a hematoma can cause them to droop

External hematomas are relatively simple to spot, but when it comes to internal hematomas it gets a little tricky. Symptoms will differ depending on what internal organ is affected by the hematoma, there might even be nothing to suggest that there’s a problem at all. Although there are various different complications an internal hematoma could cause, here are a few potential signs:

  • Seizures

  • Coughing

  • Difficulty breathing

  • Bloody spit

  • Comas

  • Neurological damage

  • Organ failure

  • Pain

  • Incontinence

The symptoms of an internal hematoma are pretty nonspecific, so diagnosis might be complicated.

How are hematomas in dogs diagnosed?

Usually, hematomas are easy to diagnose, the vet will get a relatively accurate diagnosis based on a physical examination. A sample of the hematoma will be taken to accurately determine whether the fluids are blood.

The most important part of diagnosis is working out what caused the hematoma in the first place, which might require a few different diagnostic tests.

For example, if it’s an aural hematoma, an examination of the ear canal will be necessary to determine whether an ear infection or parasites are present, which could have caused scratching and head shaking. Alongside this, skin tests may be performed to work out if hematomas were triggered by allergies and skin sensitivities.

How will hematomas in dogs be treated?

Firstly, the cause of the hematoma needs to be identified. Getting rid of parasites, treating other medical conditions or detecting any allergies is the first step to prevent the chance of any hematomas occurring again. All of these things can cause irritation, leading to scratching and head shaking which can trigger the blood vessels to burst, resulting in a self-inflicted hematoma.

The tiniest hematomas may disappear totally on their own, but your pooch will more than likely need veterinary intervention. Although hematomas don’t usually cause too many complications, you will still need the help of a vet to eradicate the blister.

You might think that because it’s simply just a blood blister, the hematoma can be left and then it will eventually vanish, however, left untreated your dog will suffer from subsequent problems. The hematoma will gradually reabsorb and disappear, but the inflammation caused by the hematoma will continue to damage the surrounding tissue.

This will lead to further pain, resulting in even more continuous scratching and head shaking which could create even more hematomas. Also, the inflammation and damaged ear tissue can potentially distort the shape of the ear forever, something that is commonly dubbed as a ‘cauliflower ear’.

One option for treatment may be to drain the blood with a syringe, which all depends on both the size and whereabouts of the hematoma. Draining isn’t always the best option however, working only as a temporary solution because this leaves ‘dead space’ where the fluid was removed, allowing a space for the blood to accumulate once again and become open to infection.

Typically, draining is performed when the hematoma is super small or if the dog is unfit for the more permanent treatment method of full surgery. If draining is the route you take, expect your dog to need to undergo this procedure multiple times to totally eliminate the issue. It goes without saying, but never try to drain the hematoma on your own.

Alternatively, surgery is a permanent solution to the hematomas. Your dog will be placed under general anaesthetic and the skin covering the hematoma will be cut to drain the blood and get rid of clots. The skin covering the hematoma will be incised, the fluid will be drained out and then multiple sutures will be placed over the area to prevent the area from refilling with blood again.

These stitches may need to be kept in for multiple weeks to allow scar tissue to form, re-connect the cartilage to the skin so future recurrence can be avoided.

Follow up treatment

Following surgery, the pinna (ear flap) will likely need to be supported with bandages against the head, stopping your dog from itching or shaking their head to relieve any irritation and as a result causing further damage to the wound and possibly even subsequent hematomas. Both the bandages and stitches will be removed after a couple of weeks.

Stick to your vet’s guidance and continue to monitor the surgery site, clean off any discharge produced from the area and watch out for any signs of infection. If an infection does occur, your vet will provide your pooch with the necessary medication.

Full recovery shouldn’t take more than 2 weeks, but this might vary depending on what caused the problem in the first place. For example, if your dog was scratching because of an allergy which lead to the blood blister, you’ll need to find out what the allergy is to reduce the risk of a hematoma happening once more.

Can hematomas in dogs be prevented?

In short, no, hematomas in dogs can’t really be prevented, as you can’t stop your dog from scratching their ears or shaking their head. However, having a general awareness of what hematomas are and what causes them is the main step you can take to preventing the problem.

Keeping up with good hygiene, regular vet check-ups and constantly checking for parasites, ear issues and skin problems are the best things you can do.


All in all, hematomas aren’t severe and can be resolved pretty easily without any complications. If your dog has a hematoma, the main thing is that you work out why they got it in the first place, as although it could have been from some minor injury, it could have stemmed from something much more serious.

  1. Epidemiological and Etiological Studies on 59 Aural Hematomas of 49 Dogs Japanese Journal of Veterinary Anaesthesia & Surgery 36, (4), Jan 2005, 87-91, doi:10.2327/jvas.36.87
  2. Aural hematoma and its treatment: A review The Canadian Veterinary Journal, 61, (3), March 2020, 313-315, PMID: 32165757