Why Dog Bite Wounds Are Like Icebergs

When it comes to dog bites — even small ones — what lies beneath is often a lot more dangerous than you’d think.

Dog bites may seem minor, but they do need to be checked out by a vet. By:
Any full-thickness dog bite that penetrates through the skin requires veterinary attention. By: tjc

Has your dog been in a fight?

As a veterinarian, I’ve seen and treated far too many dog fight injuries. As well as the physical wounds, there’s also the emotional trauma that affects them for months afterward.

When presented with a dog bite wound, I’m constantly surprised by how much damage is lurking beneath the surface. When I clip away the fur, the most obvious things are the puncture wounds left by the attacker’s teeth.

But invisible under the skin, there’s usually a big pocket of “dead space” where the dog shook his victim and ripped the attachment between skin and the underlying tissue.

Dog Bites Are Common

It is not unusual to see innocuous-looking bites go bad.

In these cases, immediately after the attack the person did the right thing and bathed the dog’s puncture wounds with disinfectant. Thinking they can see all the damage and happy that nothing needs stitching, they adopt the “wait and see” attitude.

However, the attacking dog’s dirty teeth injected bacteria deep into the subcutaneous tissue. Although the superficial wound heals over, those bacteria multiply. A few days later, an abscess develops. The dog becomes unwell and stops eating, and the abscess ruptures — leaving a nasty hole behind.

Larry the Retriever

A case I saw that did just that was Larry, a Golden Retriever. He was brought in to see me one Friday evening because he’d stopped eating and had a lump on his flank. Checking Larry over, I saw that the lump was full of fluid, and Larry had a high fever. I popped a needle into the swelling and got pus out.

The client recalled a small dog attacking Larry in the park a few days earlier. Larry had sustained a couple of puncture wounds, which were cleaned and then forgotten about.

However, Larry now had a football-sized abscess on his flank. The swelling had interfered with the blood supply to the skin. Despite treatment, an area the size of a dinner plate died off.

Happily, this story ended well, but only after major surgery and a skin graft to repair the large hole.

The moral of this story: Seek veterinary attention, no matter how small the puncture wound appears.

Why Is a Dog Bite Like an Iceberg?

Because the damage on the surface is a fraction of what lies beneath.

When a dog bites, he shakes his head. This shearing action pulls the skin away from the underlying tissues and forms a large pocket. The bite also pushes bacteria beneath the skin, so cleaning the surface is all very well, but the deeper bugs remain untouched.

While the skin wound heals, over the next few days those bacteria multiply and breed in that subcutaneous pocket without giving any hint of trouble brewing beneath the surface.

The first a person knows something is wrong is when the area swells up, and the dog becomes unwell. But an abscess isn’t all that happens. Damaged or swollen tissue becomes devitalized and dies off to form a large scab, which often peels away to leave a considerable hole behind.

If the dog is lucky, we can clean up and stitch together this deficit. But for the unlucky, like Larry, the hole is so big that it requires the canine equivalent of plastic surgery to fix it.

Tobique suffered a small bite at the dog park, and the wound was cleaned by an emergency vet. By: greencolander
Even though Tobique suffered “a small bite” at the dog park, an emergency vet evaluated the wound and cleaned it up. By: greencolander

What Should You Do?

Any full-thickness dog bite that penetrates through the skin requires veterinary attention.

These wounds need to be flushed out with sterile saline in order to wash out contaminating bacteria and debris (such as hair) that get pushed beneath the surface.

Many veterinarians — myself included — prefer to sedate the patient in order to fully evaluate the damage. Again, it’s amazing just how much hair and other debris get pushed beneath the surface, which needs removing if the area is to heal uneventfully.

This also allows me to check how deep the puncture wounds go. Again, I can think of a sweet cavalier who was bitten on the chest, and she was brought in because she was “a little quiet.” The dog’s breathing was rapid and lung sounds were muffled.

The X-ray showed air around the lungs. The attacking dog’s teeth had penetrated deep into the chest cavity and air had leaked in, which can be very serious. She improved after emergency surgery.

It was another case of a dog bite being like an iceberg because the damage could not be determined from the external marks alone.


This pet health content was written by a veterinarian, Dr. Pippa Elliott, BVMS, MRCVS. It was last reviewed Dec. 17, 2018.