A bite from another animal is never just a hole in the skin

Three different forces act at the moment of the bite. The canine teeth puncture and carry the oral bacteria of the other animal inside. The closing jaws crush muscle, vessels and nerves against the deeper structures. If the bitten animal twists away, a tearing component is added that separates skin from the underlying tissue and creates dead space where blood and serum collect.

Crushed tissue does not die immediately: it loses viability progressively over the following twenty four to forty eight hours. That is why a wound that looked minor at the first check can look far worse the next day, and why vets often schedule a review one or two days later. This is not an unexpected deterioration, it is the expected evolution of the injury.

The same wound means something different depending on where it is. Some sites carry an immediate risk to life and should be treated as emergencies even without significant bleeding.

A particularly high risk situation is a large dog grabbing and shaking a much smaller animal. The force transmitted to the chest and spine can produce rib fractures, lung contusions and internal injuries even when only two or three holes are visible on the skin. For these patients imaging is the rule rather than the exception.

The mouths of dogs and cats host a rich bacterial population that includes both aerobes and anaerobes. Among them Pasteurella multocida is a constant presence, known for causing infections that progress quickly. When these bacteria end up in poorly oxygenated, enclosed tissue, they find ideal conditions to multiply.

The decision about antibiotics, the need for drainage and whether to close the wound belongs to the vet and depends on site, depth, elapsed time and general condition. There is no home rule, and using leftovers from previous prescriptions is harmful: wrong doses and durations select for resistance and can mask a picture that was getting worse.

The priority in the first hour is twofold: stop anyone getting hurt while the animals are separated, and get the patient to the clinic in stable condition. The useful actions are few and simple.

1. 1

   Separate safely without putting your hands in

   Use a rigid barrier, a jet of water, a heavy blanket thrown over the animals, or the hind leg lift if there are two of you and you know how. Reaching between two biting animals is the most common cause of bites to people.

2. 2

   Put the animal somewhere enclosed and assess it

   Check breathing, gum colour, consciousness and ability to walk. Noisy or laboured breathing after a bite to the neck or chest is a reason to leave immediately without further checks.

3. 3

   Control bleeding with direct pressure

   Gauze or a clean cloth pressed exactly on the spot for at least three minutes without lifting. If the material soaks through, add more on top instead of replacing it.

4. 4

   Look for every hole, not just the first

   Run your hands over the whole body against the lie of the coat, especially neck, armpits, groin and back. The holes are small and become invisible in long coats. Note how many you find and where.

5. 5

   Flush only if the wound is superficial and not bleeding

   Plenty of sterile saline, or clean water. No hydrogen peroxide, no alcohol, no ointments: they make assessment harder and damage tissue.

6. 6

   Call the clinic and set off

   Tell them the species and size of the biting animal, the sites of the holes, the elapsed time and the general condition. If the other animal is known, ask its owner for vaccination status and contact details.

In cats the sequence is so regular that it works almost like a clock. Thin teeth leave tiny holes that close within hours. Over the next two to five days a warm, painful swelling appears, often at the tail base, on the back, the head or a limb, together with fever, dullness and reduced appetite. Many owners arrive at the clinic at that stage without knowing there had been a fight.

• A cat that sleeps more than usual, stops jumping and reacts when touched on one particular spot should be checked even without visible wounds.
• Cat fights are a recognised route for blood borne viruses, including feline immunodeficiency and feline leukaemia viruses: after a bite the vet may advise testing, often repeated some weeks later.
• Cats with outdoor access have a far higher risk of repeated episodes, especially if unneutered.
• Neutering reduces territorial conflict behaviour and with it the frequency of bites.
• If your cat has an area leaking foul smelling fluid, the collection has already opened: an examination is still needed, because the cavity has to be cleaned.

A bite creates consequences that do not end with the dressing. Information is needed for clinical follow up, for any insurance matter and, when a person is involved, for the public health steps required by local law.

• Exact date, time and place of the episode, with a short description of what happened.
• Species, size and, if known, identification of the biting animal, with its owner's contact details.
• Photographs of the wounds before clipping, useful for comparison over the following days.
• Number and location of the holes found, recorded even when they look irrelevant.
• Your own animal's vaccination status, with particular attention to rabies vaccination where it applies.
• The clinic name, prescribed treatments and the date of the scheduled review.
• In many European countries, including Italy, a bite to a person triggers a period of official observation of the biting animal by the public veterinary service: find out about local procedures instead of ignoring them.

Over the following days keep an eye on three things: body temperature if you can take it without stressing the animal, appetite, and behaviour around the wounds. An animal that stops eating, hides, or reacts to touch on an area it tolerated yesterday is signalling deterioration and should be seen before the planned date.