Bite Wounds in Dogs

By Krista Williams, BSc, DVM, CCRP; Ryan Llera, BSc, DVM; Cheryl Yuill, DVM, MSc, CVH

Bites wounds are one of the most common reasons dogs are seen for emergency appointments with their veterinarians.

Why do dogs bite?

In puppies, biting is often part of aggressive play. In adult dogs, biting or other aggressive behaviors can have multiple underlying motives or causes. Aggressive behaviors such as growling, lunging, snarling, snapping, or biting are used as a means of communication and to resolve competitive issues or perceived threats. The competition may be over food, territory, attention from an owner, position in a pack or group, or as a protective reaction towards another dog.

How serious are dog bite wounds?

Dog bites can cause significant injury to the skin and soft tissues. The dog's teeth and jaws are very powerful and the wounds they inflict can crush or tear muscles and skin, penetrate through the chest wall and cause lung collapse, or cause serious or fatal damage to intestinal organs. Even a bite that does not break the skin can cause crushing or bruising injuries to the underlying soft tissues.

"Bite wounds are commonly inflicted on the legs or around the head and neck."

Bite wounds are commonly inflicted on the legs or around the head and neck. Vital structures in the neck that could be easily injured include major blood vessels, numerous nerves, the esophagus (tube connecting the throat with the stomach), and the trachea (windpipe). Wounds on the face can cause severe damage to the eyes, ears, or mouth. With bite wounds on the legs, there is a risk that the injury can involve the joints.

Since the dog's mouth is full of bacteria, any bite that does puncture the skin will introduce bacteria or other infectious organisms below the skin surface, where the bacteria can multiply and spread throughout the underlying tissues. All bite wounds are considered to be contaminated and/or infected. Left untreated, the bacteria in an infected bite wound will cause a localized abscess or more generalized cellulitis (a tissue infection) that spreads through the surrounding area. In rare cases, a penetrating bite wound can cause septic arthritis (infection of the joint), osteomyelitis (infection of the bone), pyothorax (pus in the chest cavity), or septic peritonitis (pus in the abdominal cavity).

Does my dog need to be seen by a veterinarian after it has been in a fight?

If your dog has been involved in a fight, it can sometimes be challenging to determine the extent of the injuries, particularly if the wounds are located in heavily furred areas of the body. Small puncture wounds from canine teeth can close over rapidly and can easily be missed. If your dog has been in a fight with another animal, take him to your veterinarian for an examination as soon as possible. If you can see obvious bite wounds, you should seek immediate veterinary attention. Wounds that appear to be minor on the surface can be deceptive and may have the potential to be life-threatening, depending on the location of the injury.

What should I look for to determine how quickly my dog needs to see the veterinarian?

There are certain signs that require immediate emergency treatment. These include uncontrollable bleeding, breathing difficulty, weakness, crying or whining, limping, pale or blue gums, or collapse.

How are bite wounds treated?

Your veterinarian will determine what sort of treatment is necessary, based on the extent of the injuries, your dog's general health, and the location of the wounds. The goal of treatment is to reduce the severity of any infection that develops. This will be accomplished by cleaning the wounds, removing any dead or severely damaged tissue, and potentially surgically closing the wounds.

Antibiotics may be prescribed for wounds that have penetrated the skin depending on the location of the wound and the duration between bite time and presentation to your veterinarian. For minor injuries, or for wounds that must be left open to heal, your veterinarian may prescribe a topical antibiotic. If there is any doubt about skin penetration, your veterinarian may prescribe a broad-spectrum antibiotic such as amoxicillin-clavulanate (Clavamox®) or, for more complicated cases, enrofloxacin (Baytril®), to lessen the chance that a serious infection will develop. The sooner antibiotics are started after a bite injury the quicker the infection will be brought under control. Wounds that are treated within six hours of the injury have the best chance of healing without complications.

"Wounds that are treated within six hours of the injury have the best chance of healing without complications."

Most wounds are painful, and it is more humane for your dog to be given some sort of pain medication, sedative, or anesthetic before attempting to assess the extent of the injuries. Your veterinarian will then shave the fur off of the skin that surrounds the wounds to lessen the potential for further contamination and will flush the wounds to remove any contaminants and debris. For extensive wounds, severely contaminated wounds, or wounds in sensitive areas of the body (such as near the eyes, mouth, or ears), it will be necessary to put your dog under a general anesthetic so that the area can be safely and thoroughly cleaned and treated. Additional pain medications will be sent home, most typically non-steroidal anti-inflammatory drugs (NSAIDs) such as meloxicam (Rheumocam®, Metacam®), deracoxib (Deramaxx®), or carprofen (Rimadyl®).

Small puncture wounds will usually be left open so that any infection can drain out. Lacerations will be sutured up, and temporary drains may be placed if the damage is extensive, or if there is a chance that fluid will build up in the area. Most lacerations will be debrided, meaning any infected or severely damaged skin tissue will be cut away and the edges of the laceration will be trimmed. In many cases, skin wounds will be enlarged to allow the underlying tissues to be thoroughly examined and cleaned.

Experts recommend that bacterial culture and sensitivity tests should be performed to determine the type of bacteria involved and the best antibiotics to treat these bacteria. However, it takes a couple of days for the test results to be ready, so your veterinarian may not perform these tests unless your pet's wounds do not respond appropriately to initial broad-spectrum antibiotic treatment.

How do I care for my dog after being treated for a bite wound?

If your dog's wounds have been closed with sutures, you will need to keep the area clean and dry. He may need to wear an E-collar (Elizabethan collar or cone) or a bandage may be applied to cover the site (see handout “Bandage and Splint Care in Dogs”).

If the wound has been left open to heal, or if a drain was placed in the wound, you will need to clean away any draining material on a regular basis. You can use a clean, soft washcloth or cotton balls with warm water to remove debris. In some cases, your veterinarian will prescribe a mild disinfectant cleanser to assist with keeping the area clean. Only use products that are recommended by your veterinarian. Never use hydrogen peroxide to clean a bite wound unless specifically instructed to do so by your veterinarian, as this can delay healing and can worsen the problem.

"Never use hydrogen peroxide to clean a bite wound unless specifically instructed to do so by your veterinarian..."

If you have been instructed to clean the wounds, use extreme care as they may be painful, and your dog may bite you due to pain or fear. It is advisable to use a muzzle on your dog, even if he is normally extremely gentle.

What can I do to prevent bite wounds?

Do not allow your dog to roam freely, and keep your dog on a tight leash when you are outdoors, especially if you are in a park. Dogs that are well-mannered are less likely to fight, so basic obedience training is strongly recommended starting at a young age. If you are outdoors with your dog and you see a roaming stray dog, do not approach it. Even if your dog is gentle and friendly, you have no way of knowing the temperament of the other dog.

As a preventative measure, you should always make sure your pet's rabies vaccine is always up to date (see handout “Rabies Vaccines in Dogs” for more information).

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