Abscesses in Dogs

What are Abscesses in Dogs?

An abscess is a pocket of inflammation that typically has a “wall” of tissue surrounding it. The center is filled with either thick liquid or solid material consisting of white blood cells, dead tissue, and sometimes bacteria.  

There are four common locations for abscesses in dogs. 

Teeth: In a dental abscess, there is infection involving the root of a tooth. The bony socket surrounding the affected root is usually eaten away by the infection, and the surrounding gum is inflamed. 

Skin: Trauma from a bite, a splinter, or something sharp your dog has stepped on can insert bacteria and other foreign debris under the skin. As the wound heals, it may seal up quickly, trapping bacteria and/or debris and leading to the formation of a fluid-filled, inflamed, painful lump.  

A hot spot (acute moist dermatitis) is a type of abscess that forms on the surface of the skin, commonly because of skin allergies. The area becomes itchy, and the dog traumatizes it by chewing or licking excessively. The skin can become infected with bacteria and/or yeast. 

Anal sac: There are internal sacs on either side of the anus that normally contain a fluid that is emptied when a dog has a bowel movement. If the liquid substance becomes too thick to drain properly, the anal sac is never emptied. The fluid continues to accumulate, and the sac becomes inflamed. 

Infected neoplastic mass: A cancerous mass can become abscessed if it outgrows its blood supply. Sometimes the mass will be unchanged for an extended period, then suddenly become painful and inflamed. 

Symptoms of Abscesses in Dogs

Depending on the site of the abscess, a dog may exhibit different signs: 

• Dental abscesses are painful and may also be associated with an odor or drool (sometimes blood-tinged). A dog with a dental abscess may not be eating normally and may prefer soft food over hard food or treats. Avid chewers may stop chewing toys and bones they once enjoyed. There may also be facial swelling in the region of the affected tooth.   

• Skin abscesses are painful, warm, soft, or firm lumps. If the abscess is on a paw or leg, you may notice your dog limping. Your dog may cry out or wince if you touch the abscess site. 

• Anal sac abscess pain may result in a dog licking excessively under the tail, scooting on the floor, or straining to have a bowel movement. If the anal sac has ruptured through the skin, you may notice drainage from the site. 

Causes of Abscesses in Dogs

Dental abscesses 

• Dental disease—tartar accumulation and gingival inflammation 

• Fractured (broken) tooth, with bacteria invading the pulp cavity 

• Foreign material stuck in the mouth, such as bone pieces, sticks, metal, plant material, hair 

Skin abscesses  

• Any type of penetrating trauma, such as bite wounds or stepping on a foreign object 

• Excessive licking or chewing due to skin allergies 

Anal sac abscesses 

• Thick anal sac material blocking the duct (tube) through which the anal sac empties 

How Veterinarians Diagnose Abscesses in Dogs

Abscesses are typically identified during a physical exam. If a firm lump is found, your vet may perform a fine needle aspirate, which involves inserting a needle into the mass to collect cells. The sample is then evaluated under a microscope to determine what type of cells are present. Abscess samples contain a lot of white blood cells, and bacteria or fungal organisms may be seen.  

If an abscess does not respond to initial treatment, fluid or material from the site can be put in the incubator to culture (grow) the bacteria involved. Then, antibiotics are tested to see which will be most effective. Bacteria that are resistant to antibiotics can be found in dogs, just as in humans. 

Treatment of Abscesses in Dogs

There are multiple treatment options a veterinarian may recommend depending on the dog’s diagnosis. One option includes opening and draining the site and removing the source of infection. This may involve extraction of an abscessed tooth, removal of foreign material stuck under the skin, or flushing the anal sac duct to re-open it.  

Simple skin abscesses may be addressed under local anesthesia, depending on the location. Complicated sites (especially the face) or involved cases (such as dental or large abscesses) will be addressed under general anesthesia. For cleaning hot spots, trimming away the hair can often be done without any form of anesthesia. There are some hot spots, however, that are very painful, and the dog may benefit from sedation for clipping/cleaning of the site. 

Often, oral antibiotics are administered to a dog with an abscess. Pain medication, including an anti-inflammatory medication, is also important. Also, warm compresses applied to a painful, inflamed site help to enhance blood flow and clean the area. This is frequently recommended for the pet parent to do at home for several days. 

Recovery and Management of Abscesses in Dogs

Usually, once the cause of the abscess is addressed and the dog is on appropriate treatment, an abscess starts to resolve quickly, within 2-3 days. The dog should start feeling better quickly as well.

Your vet will likely want to recheck your dog a week or two into treatment to see how the abscess site looks. For long-term management, your vet will make recommendations regarding future dental care (for a dental abscess), routine anal sac expression (for an anal sac abscess), and skin allergy management (for hot spots).