Dogs can develop abscesses from a wound, inappropriate chewing, a bad tooth, or on their anal glands. If you notice that your dog has developed a soft swelling, a sore that's draining pus, or an area that's hot and/or painful when touched, it's time to call the vet. Although there are home treatments that can reduce your pup's pain, if left untreated, the infection has the potential to severely damage your dog's health.
Why Do Dogs Develop Abscesses?
An abscess results from the body's attempt to wall off an infection. The fight against infection results in an accumulation of white blood cells and other blood components commonly called pus. This liquid collects in a fleshy pocket in the tissue that swells and becomes very painful. This swelling is called an abscess.
Almost anything, such as a bite wound, splinter, or even an insect sting, can result in an abscess if the surface of the skin is penetrated. When the skin surface heals over the wound, bacteria become sealed inside, the body’s immune system is activated, and a pocket of infection may form.
More rarely, a “sterile abscess” can develop without any visible break in the skin. For instance, a bruise that causes tissue swelling and inflammation may develop a pocket of infection.
Some abscesses can also occur internally from bacteria or foreign material that gets in through the digestive tract, urinary tract, respiratory tract, or other ports of entry into the body.
The signs of an abscess include a soft swelling, often with drainage of green, yellow, or even bloody pus from the infected site. Abscesses are usually painful, very tender, and feel hot to the touch. It's common for a dog with an abscess to also develop a fever, act lethargic, lose its appetite, or become reluctant to move or have the area touched.
Bite wounds that plant infectious organisms deep into the tissue are the prime cause of abscesses in dogs. Dogs may also develop abscesses from being bitten or scratched by a miffed cat. These are commonly found in the head and neck region or near that tail but may appear anywhere on the body. Head and neck abscesses typically cause one side of the neck to swell.
Abscesses may result from chewing an inappropriate object that splinters. In these cases, the abscess may develop on the tongue, gums, cheek, or behind the eye.
Dogs may suffer from tooth abscesses, or pockets of pus that form in teeth due to infection, especially in teeth that are broken while chewing or that suffer from periodontal disease. An abscessed tooth may cause your dog to drool or refuse to eat and could turn into a life-threatening condition if not treated.
Dogs also commonly suffer from anal gland abscesses, in which the area around the rectum becomes red, swollen, and tender. Once the abscess bursts, you may notice smelly, wet hair at the infection site.
Your veterinarian generally makes the diagnosis of an abscess from the signs. At other times, they may insert a needle into the swelling and draw off material to see if an infection is present.
If your dog has a heavy coat, the injury may be hidden from view. You might not notice the problem until your dog is in pain and flinches when you touch it or the abscess begins to drain. As the injury swells with pus, the skin stretches and becomes thin until it ultimately ruptures, possibly soaking the surrounding hair.
An abscess should be treated as soon as possible to prevent further damage to the surrounding area. Otherwise, the infection can spread until nearby tissue dies, muscles or nerves are damaged, and/or the resulting wound is difficult to heal.
In most cases, an abscess is so painful that your dog must be anesthetized before the vet can treat it. First, the hair around the swelling is clipped, and the area is disinfected with a surgical scrub solution like povidone-iodine. Then the wound is lanced, the pus is drained, and the abscess is flushed with a solution to clean out the inside of the infected pocket.
When the abscess is very deep or intrusive, a drain or “wick” may be surgically stitched in place to keep the area draining as the surface skin heals. This can help prevent the abscess from recurring. Oral antibiotics are often prescribed as well. When the surgical site is within reach of your dog's teeth, an Elizabethan collar or e-collar prevents your dog from bothering the wound while it heals.
If you notice swelling and suspect an abscess, your veterinarian may recommend warm, wet compresses to help the sore come to a head. If your dog allows you to do this, do it several times a day for five minutes on, five minutes off, until the compress cools.
Drainage makes the hair wet and smelly, and the hair can hold bacteria in place and slow healing, which means you'll need to clip long hair away from the infected area. Your veterinarian will still need to evaluate the abscess site and possibly prescribe medication to fight further infection.
Help prevent abscesses by reducing the probability of injury. For example, neuter or spay your dog to greatly diminish aggression that could result in bite wounds. Also, supervise your pet when it's gnawing on dog chews and only offer safe alternatives. Good dental hygiene and routine care of anal glands will help reduce the risk of abscesses in these areas as well.
Abscesses In Dogs. VCA Animal Hospitals, 2020.
Borkowski, Emma A. Retropharyngeal Abscess With Carotid Involvement Presenting as Fever of Undetermined Origin in a Dog. The Canadian Veterinary Journal, 2014.