An abscess is defined as a sac or lump that contains pus. Abscesses are generally caused by bacteria, parasites, or foreign material under the skin. Trauma to the skin or underlying tissues may predispose to infection and abscess formation.
The hallmark signs of an abscess are pain and swelling in the area, as well as redness and an increased temperature of the skin overlying the abscess.
In the initial stages of abscess formation, the body's immune system detects an abnormality under the skin, which could be bacterial or foreign material or the death of cells caused by trauma or parasites. Once the immune system detects an abnormality, it increases the blood flow to that area; the blood vessels dilate, allowing certain white blood cells to gain access to the abnormal area. These white blood cells attempt to rid the area of the bacteria, foreign material or dead cells.
Pus is formed when the white blood cells die and accumulate in the affected area. As a protective mechanism the immune system also works to wall off this area from the rest of the body, by forming a fibrous capsule. This fibrous capsule keeps the pus confined to one area. If the bacteria or foreign material overwhelms the immune system, the pus continues to accumulate and the abscess becomes larger.
As time goes on, the wall surrounding the ever-growing pus pocket becomes thin, and at some point, it ruptures and pus drains out. Typically, the abscess ruptures to the exterior of the body, and you'll see the pus draining from the wound.
Some abscesses heal without treatment if the white blood cells are able to destroy the invading cells. In this case, the active source of continued infection will be eliminated and the body will slowly absorb the pus that was created during the battle to destroy the invading material.
Frequently, though, abscesses do not heal without treatment and veterinary care is recommended.
Most commonly, abscesses are related to a recent cat fight or other penetrating puncture wound. These should be treated by your veterinarian.
What to Watch For Redness, swelling pain and/or discharge coming from the skin
Skin may be warmer at the affected area
Diagnosis is generally based on physical exam findings of an abnormal lump. If the abscess has not ruptured, inserting a needle into the lump and drawing back on the syringe may indicate the presence of pus. If the abscess has ruptured, the diagnosis is made based on the presence of a lump with pus draining from the open wound.
Treatment for an abscess depends of whether the abscess has ruptured. For abscesses that have not ruptured, an area of the skin over the lump is cleaned and the abscess is lanced. Pus will drain from the lump. This procedure may require heavy sedation or general anesthesia for your cat.
At this point, treatment for ruptured and non-ruptured abscesses is the same.
After a majority of the pus has been removed from the abscess, a disinfectant solution such as povidone iodine or chlorhexidine is used to further flush the abscess and remove additional pus. After a thorough cleaning, antibiotics are generally prescribed to hasten healing and eliminate infection.
Home care for an abscess is aimed at helping the body's immune system fight off the infection. This may include the application of warm compresses for about 5-10 minutes 3- 4 times per day to help increase the flow of blood to the area. This in turn will increase the white blood cell population within the abscess, to better fight the infection.
If the abscess has ruptured, thorough cleaning is recommended. Often the wound is left open to drain during the healing process. During healing, it is imperative that your cat does not lick or chew at the abscess. Saliva is contaminated with bacteria and will only prolong and prevent healing. If you cannot keep your cat from licking at the area, an Elizabethan collar may be needed.
Antibiotics should be administed as directed by your veterinarian.
The best way to prevent abscesses is to try to prevent injuries that could result in abscesses. Keeping your cat away from other aggressive animals can reduce the chances of fights.
Also, prompt veterinary care after a fight, trauma or penetrating wound can prevent the formation of an abscess.