What is a skin abscess?
A skin abscess, also called a boil, is a bump that appears within or below the skin’s surface. This bump is usually full of pus or translucent fluid. It’s typically due to a bacterial infection.
A skin abscess may appear on any part of the body. However, abscesses most commonly develop on the back, face, chest, or buttocks. Skin abscesses can also appear in areas of hair growth, such as the underarms or groin.
Most skin abscesses are harmless and may go away without treatment. Over-the-counter creams and medications may be all that’s needed to help speed the healing process of a minor abscess. Sometimes, skin abscesses are more difficult to treat and may require laceration or drainage.
There are cases in which an abscess can lead to serious, potentially life-threatening complications if left untreated.
Common causes of a skin abscess
Staphylococcus is the most common bacterial cause of skin abscesses. A skin abscess can be the result of a bacterial infection that occurs when Staphylococcus aureus bacteria enter the body through a hair follicle or through a wound or injury that has punctured or broken the skin.
You’re at increased risk for this bacterial infection if you have:
- close contact with an infected individual (which is why staph infections are more common in hospitals)
- a chronic skin disease, like acne or eczema
- a weakened immune system, which can be caused by infections such as HIV
- poor hygiene habits
Infected hair follicles
Infected hair follicles, or folliculitis, may cause abscesses to form in the follicle. Follicles can become infected if the hair within the follicle is trapped and unable to break through the skin, as can happen after shaving. Trapped hair follicles are commonly known as ingrown hairs. Ingrown hairs can set the stage for an infection. Abscesses that are on or in a hair follicle will often contain this ingrown hair.
Folliculitis may also occur after spending time in an inadequately chlorinated pool or hot tub.
Identifying a skin abscess
An abscess often appears as a bump on the skin, similar to a pimple. However, it can grow over time and resemble a cyst filled with fluid. Depending on the cause of the abscess, other symptoms may also be present. These symptoms may include:
- lesions on the skin
- inflamed skin
- fluid drainage from the abscess
The area around the abscess may also feel painful and warm to the touch.
Diagnosing an abscess
One small boil isn’t usually a cause for concern. You can often treat it at home. However, if you have a boil and any of the following apply to you, see your doctor as soon as possible:
- You’re a child.
- You’re over the age of 65.
- You have a weakened immune system or you were recently hospitalized.
- You have received an organ transplant.
- You’re currently on chemotherapy or you recently received chemotherapy.
- Your skin abscess is on your face or spine. (If left untreated, the abscess may spread to your brain or spinal cord.)
- The abscess is large, hasn’t healed within two weeks, and you also have a fever.
- The abscess appears to be spreading to other parts of your body.
- The abscess is becoming more painful or is throbbing.
- Your limbs are swollen.
- Your skin around the abscess is swollen or extremely red.
Your doctor will review your medical history and perform a physical examination to visually inspect the abscess. A complete physical examination allows your doctor to tell if an injury or ingrown hair is the cause of the abscess.
Your doctor may also take a culture or a small amount of fluid from the abscess to test for the presence of bacteria. No other testing methods are necessary to diagnose an abscess. However, if you’ve had reoccurring skin abscesses and your doctor feels that an underlying medical condition may be the cause, they may take a blood or urine sample.
Complications of a skin abscess
In some cases, an abscess may cause serious complications. These may include:
- the spread of the infection, potentially to the brain or spinal cord
- blood poisoning, or sepsis
- endocarditis, which is an infection of the inner lining of the heart
- the development of new abscesses
- tissue death in the area of the abscess, such as gangrene
- an acute bone infection, or osteomyelitis
Methicillin-resistant Staphylococcus aureus (MRSA) is another potential complication. MRSA is a drug-resistant strain of the bacteria that commonly cause skin abscesses. While there are alternative antibiotics to treat this strain, they don’t always work.
How to treat a skin abscess
Home treatment options
You can usually treat a skin abscess at home. Applying heat to the abscess can help it shrink and drain. The most useful way of applying heat is to put a warm compress on the abscess. You can make a warm compress by running warm water on a face towel and folding it before placing it on the abscess.
See your doctor if the abscess is stubborn and doesn’t heal using home methods. They may want to drain it. To drain the abscess, your doctor will apply numbing medications and will then cut the abscess open to allow the fluid to come out. After the abscess drains, your doctor will pack the wound with surgical material. This helps it to heal and prevents the abscess from reoccurring.
After the procedure is over, your doctor will likely prescribe antibiotics to prevent the wound from becoming infected.
Severe cases of skin abscesses are generally also treated with antibiotics. Your doctor may prescribe an antibiotic such as dicloxacillin or cephalexin if you have any of the following:
- an abscess on the face, which has a higher risk of causing complications
- more than one abscess
- a compromised immune system
If your doctor thinks MRSA is the cause of the abscess, they may prescribe clindamycin or doxycycline to fight the infection.
After treatment, the abscess shouldn’t return.
How to prevent a skin abscess
You may not always be able to prevent a skin abscess. However, there are ways to minimize your chance of acquiring the staph infection that commonly leads to an abscess. To minimize your risk of a staph infection:
- Wash your hands regularly.
- Clean all cuts and scrapes, even small ones, with soap and water and apply an over-the-counter antibacterial ointment.
- Keep your cuts and wounds bandaged.
It’s also best not to share personal items, such as towels, sheets, razors, athletic equipment, makeup, and clothing. If you do have a cut or sore, wash your bedding and towels in hot water, detergent, and bleach regularly and dry them on the hot setting.