What is a skin abscess?
A skin abscess is a pocket of pus that forms beneath the skin. (Pus contains white blood cells, dead skin cells, bacteria, and liquid.) Skin abscesses are usually caused by infections from the bacteria, Staphylococcus aureus (also called staph).
In some cases, abscesses can be caused by other bacteria such as the drug-resistant form of staph, called MRSA (methicillin-resistant Staphylococcus aureus). Sometimes skin abscesses are referred to as staph infections or boils.
You can get skin abscesses anywhere on your body. However, they are more likely to form in damp, closed-off areas like the armpits and groin. Skin abscesses are usually treated by draining the pocket of pus. Sometimes, antibiotics are required to get rid of the infection.
Most common symptoms
Abscesses can be very painful—hot and throbbing—but usually resolve quickly with treatment. Though sometimes they start small but progress rapidly. Left untreated, there is a potential to develop a larger, more severe soft tissue infection that could spread to other parts of the body. —Dr. Mollie MacCormack
A skin abscess feels like a swollen pocket of fluid in or beneath the skin. It may feel firm or squishy. The skin around the abscess will likely be red and hot. You might also have pain when you touch the abscess and surrounding area.
Some abscesses form a head. This means that you can see yellow pus on part of it (similar to a pimple). They might open on their own and drain yellow pus or bloody fluid.
- A firm, yet squishy lump in under the skin
- Redness around the abscess
- Hot to the touch
- Pain around the abscess
- It may have a white or yellow “head”
- May drain yellow pus or red, bloody fluid
Other symptoms you may have
In severe cases, you may develop a body-wide infection. You may have fevers, chills, a fast heart rate, and generally feel bad.
An abscess can be confused with more serious skin infections that need to be treated right away to prevent rapid progression and tissue damage. Watch out for any of these signs that indicate a medical emergency:
- Crackling sensation felt under the affected skin
- Dark brown discharge from a wound in the area
- Extreme pain
- Numbness by the lump
- Skin looks purplish-grey or black
What to do next
Skin abscesses don’t usually go away on their own. They can get worse and become larger, progress to cellulitis (infection of the surrounding soft tissue) or become body-wide infections, such as a bloodstream infection. If you think that you have a skin abscess, you should see your doctor or go to urgent care.
If you have any of the following symptoms, see a doctor immediately or go to the ER. It’s possible that you have a more serious and possibly dangerous infection.
- The abscess and surrounding skin becomes hot and red
- It spreads quickly
- It becomes very painful
- The skin becomes gray or black
- You develop a fever
Skin abscess causes
A skin abscess typically occurs when bacteria gets underneath the top layer of the skin. This can happen because you have a cut, a bite from an insect or animal, a puncture from a needle, or from a surgical wound. Sometimes an abscess occurs without any noticeable trauma.
Your immune system responds by sending in white blood cells (immune cells) and walling off the infection beneath the surface of the skin. Pus then collects in this pocket causing the abscess.
It is typically caused by Staphylococcus aureus bacteria, or in some cases, MRSA. In rare cases, abscesses may be caused by other types of bacteria or fungi.
Very rarely, abscesses may form as a part of an auto-immune syndrome (without any infection at all). These syndromes will generally cause many abscesses that come back frequently throughout life.
What increases your risk of a skin abscess?
Certain circumstances or conditions can make you more susceptible to skin abscesses:
- Having any trauma to the skin: This includes cuts, insect or animal bites, punctures of the skin for IV or medical device placement, or incisions during surgery.
- Individuals with weakened immune systems: This includes people on immunosuppressive medications and those with immunosuppressive diseases.
- Certain individuals or families are more likely to keep getting abscesses because they are prone to bacterial colonization. Staph and other types of bacteria can live on the body in places like the nose and under the fingernails.
How do you treat a skin abscess?
Ultrasound is increasingly used to identify depth, location and efficacy of drainage of complicated abscesses. This has allowed for smaller skin incisions to be used, which ultimately results in less scarring. —Dr. MacCormack
Your doctor will probably drain the pus in a procedure called “incision and drainage.” Ultrasound may be used to help identify the location and size of the abscess. The area will be numbed using a local anesthetic. Then, a surgical knife is used to open the abscess and drain the pus. The abscess is then cleaned out with a sterile saline solution.
You may need to take oral antibiotics. This is more likely if you have a fever, the abscess could not be completely drained, or you have surrounding cellulitis. If there is no drainable pocket of fluid, you may only need antibiotics. This typically happens if an abscess is detected and treated early.
If you were treated with incision and drainage with wound packing, follow up with your doctor as directed. This ensures that the wound packing is replaced regularly and removed at the appropriate time.
If abscesses do not go away, or if they come back frequently, you should discuss this with your doctor.
Oral antibiotics require a prescription. Your doctor will choose one based on your background and the severity of your infection. Sometimes a culture will be performed to confirm the correct antibiotic has been prescribed. If you are prescribed antibiotics, be sure to complete the full course, even if symptoms have improved.
If you repeatedly get abscesses, there are extra steps you can take to help prevent them. Discuss these strategies with your doctor before trying them.
- Antibacterial soap: Special soaps, like chlorhexidine wash (Hibiclens), can reduce staph and other bacteria on the skin.
- Bleach baths: Bathing in diluted bleach (as directed by your physician) can help to reduce bacterial populations on your skin.
- Decolonization: Reduce staph populations in your nose by applying a prescription antibiotic ointment to the inside of your nostrils. Your housemates or family members may also need to do this to prevent spreading the bacteria back and forth to each other.