A skin abscess or boil is a bump on or below the surface of the skin. Abscesses usually contain pus or clear fluid and can appear anywhere on the body.

Most skin abscesses are harmless and heal on their own. In some cases, however, they require medical intervention.

In this article, we outline the symptoms, causes, and treatments for skin abscesses. We also cover potential complications and when to seek medical care.

A skin abscess looks much like a pimple, but it is larger. It is also usually deeper under the skin.

Abscesses contain pus or clear fluid and typically do not pose a threat to a person’s health. Larger abscesses may require medical intervention, but they are not necessarily dangerous.

However, in some cases, leaving a skin abscess untreated can lead to severe complications.

Skin abscesses can occur all over the body but are common in the following areas on the body:

  • under the arms
  • on the lower back
  • around the genitals and anus

A bump on the skin may be an abscess if it:

  • is firm yet squishy
  • is round
  • contains pus
  • is painful, swollen, and red
  • is hot to the touch, which means it is likely infected
  • features a punctum, a pinpoint opening at the center

People with an infected abscess may also have a fever and swollen lymph nodes.

Abscesses that do not contain bacteria are typically painless and do not show signs of infection.

People can develop skin abscesses for a variety of reasons, but the most common cause is bacterial infection.

The bacteria typically enter the skin through a hair follicle, puncture wound, or cut to the skin. Sometimes abscesses form around a foreign object, such as a splinter or piece of glass stuck in the skin.

Bacteria that can cause abscess infections include:

Other less common causes of skin abscesses are:

Some people have a higher risk of developing infected skin abscesses, including:

  • those with obesity
  • those who smoke
  • people with diabetes
  • people with compromised immune systems
  • those who use drugs intravenously

If a person has an infected or painful abscess, a healthcare professional will usually drain it of fluid by making an incision. They may administer local anesthetic to numb the skin for this procedure.

They will then flush the cavity with a saline solution. Healthcare professionals typically leave abscesses open to allow any remaining pus to drain out. If an abscess is very deep, a healthcare professional may pack the wound and insert a wick to aid with drainage.

Depending on the type of infection, doctors may prescribe antibiotics. However, the American College of Emergency Physicians recommend avoiding antibiotics in most cases.

At-home care after medical drainage involves slowly removing packed gauze from inside the wound. Sometimes people will need to have a healthcare professional pack the wound multiple times during the healing process.

People should use moist, warm compresses to encourage wound drainage and prevent the abscess from forming again.

It is also possible to treat boils at home using:

  • a heat pack to increase blood flow and help fight infection
  • over-the-counter (OTC) medications, such as antibiotic ointments, to soothe the skin, speed healing, and prevent infection
  • other OTC medications, such as nonsteroidal anti-inflammatory drugs, to help with pain and swelling

People should not try to drain an abscess at home. If a person does this, they risk introducing bacteria into the wound, which can lead to complications.

An infected abscess that a person leaves untreated can spread to the bloodstream and lymph nodes, which can be life threatening. An untreated infection may also lead to gangrene.

Treatment may be difficult in cases where MRSA causes the infection.

If an abscess is due to an infection, a person can take the following steps to help prevent more abscesses from forming in the future:

  • practicing good personal hygiene, including washing the hands
  • avoiding using shared equipment and items such as towels to limit transmission of the infection
  • disposing of bandages and tissues properly
  • shaving carefully to prevent nicks and cuts on the skin
  • following a healthful diet
  • quitting smoking
  • maintaining a healthful weight

Often, a skin abscess is nothing serious. However, sometimes medical attention is necessary.

People should seek immediate medical attention if they:

  • have signs of a serious infection, such as fever
  • experience recurring abscesses
  • are immunocompromised
  • have a chronic condition or illness, such as diabetes

While most skin abscesses are nothing to worry about, some may require a healthcare professional’s attention. It is possible to treat a small abscess at home by applying heat to shrink and drain it.

If an abscess is large or infected, a doctor will cut it open to drain the fluid buildup.

If a person suspects they have an infected abscess, they should seek medical attention. Untreated infected abscesses are potentially life threatening, especially if the infection is the result of MRSA.