This swelling of the ear flap (the “pinna”) is technically called an “aural haematoma”, and it’s a really common problem! Unfortunately, there isn’t necessarily one easy solution. In this blog we’ll look at the underlying causes, management and prevention of these irritating “cauliflower ears”.
Why does it happen?
Ultimately, your dog is shaking their head because they have itchy ears. There are a wide range of possible underlying causes, which we’ll look at in a moment. However, whatever the cause, the itching leads to shaking, and the shaking ruptures little blood vessels inside the ear flap.
A dog’s ear flap is supported by strips of cartilage, a biological substance a bit like stiff rubber (we have it in our ears and noses too!). In some breeds, it’s really quite rigid, giving them upright, pricked ears, and these dogs are less likely to develop aural haematomas. However, if this cartilage is quite soft and flexible, giving them floppy ears, then when they shake their heads the ears go flying, generating significant centrifugal forces*! This force causes blood vessels to rupture, resulting in internal bleeding inside the ear flap.
Now, fortunately, there isn’t a lot of space in between the layers of skin and cartilage, so the dog isn’t going to be put in danger by this. However, enough blood may pool to form a “haematoma” – like a blood blister, a bruise filled with liquid blood. The more they shake their heads, the more blood vessels are damaged, and the bigger it gets.
*(Yes, physicists, I know that technically it is a centripetal acceleration, but here we’re interested in the reaction force, pushing blood into the distal pinna under increased pressure.)
How can it be managed?
There are several different management options available:
- Leave it alone. Eventually, the blood inside the ear will clot and will then be replaced with scar tissue. The bad news is that your dog will be left with a permanently swollen “cauliflower” ear. That’s why we don’t usually recommend this, except in animals where the other options are too high a risk (e.g. dogs with a clotting disorder).
- Drain the fluid out. This is quick and easy, and can usually be done in the consult room. Essentially, we just put a needle into the haematoma (it’s normally quite painless) and drain out the blood. However, while this works brilliantly for an hour or so, in many cases the only thing stopping those ruptured vessels from bleeding is the pressure of blood inside the haematoma – the site is still very, very inflamed. As a result, if we just drain it, there’s a high chance it will just re-fill.
- Drain the fluid and inject an anti-inflammatory medication. A modification to the basic drainage procedure above is to drain the fluid, and then inject an anti-inflammatory steroid into the cavity. This reduces the inflammation, reducing the risk of further bleeding and the cavity re-filling, and is effective in about 50% of cases.
- Surgery is, however, the most effective option. It is a straightforward procedure in which the cavity is drained of fluid (just like above), but is then stitched closed so it cannot refill. In some case, stents (e.g. buttons!) are stitched over the skin to apply pressure while it heals; occasionally, we may put a drain in too so any extra fluid can ooze out on its own. This has the best outcome, but does of course require an anaesthetic.
How do we prevent it happening again?
Easy – stop their ears from itching! In many ways, we can actually see aural haematomas as a symptom of ear disease. In dogs, the most common causes of itchy ears include:
- Foreign bodies – typically, a grass seed in the ear canal. Remove the seed, treat any infection, and the problem goes away!
- Ear mites – these little critters (Otodectes cyanotis) live inside the ear, eating ear wax. However, their tiny feet are really itchy, and they are a common cause of ear-related misery.
- Allergic skin disease – allergies to anything (pollen, mites, food) and some diseases such as Atopic Dermatitis tend to affect the ears before they affect other parts of the skin.
- Ear infections – most ear infections in dogs are secondary to something else (e.g. mites, or allergies). However, occasionally dogs do develop primary infections, especially if they have very droopy ears (so air can’t get into the ear canal) or if they swim a lot (having stagnant water in your ear canal isn’t conducive to good ear hygiene!).
Whatever the cause, we’ll need to find out what it is and treat it, or else those itchy ears will just keep getting worse!
If your dog has itchy ears, make an appointment to get them checked out by one of our vets.