What is a boil?

A boil, also referred to as a skin abscess, is a localized infection deep in the skin. A boil generally starts as a reddened, tender area. Over time, the area becomes firm and hard. Eventually, the center of the abscess softens and becomes filled with infection-fighting white blood cells that the body sends via the bloodstream to eradicate the infection. This collection of white blood cells, bacteria, and proteins is known as pus. Finally, the pus "forms a head," which can be surgically opened or spontaneously drain out through the surface of the skin.

What are the types of boils?

There are several different types of boils. Among these are

• furuncle or carbuncle,
• cystic acne,
• hidradenitis suppurativa, and
• pilonidal cyst

What is a furuncle or carbuncle?

A furuncle or carbuncle is an abscess in the skin caused by the bacterium Staphylococcus aureus. A furuncle can have one or more openings onto the skin and may be associated with fever or chills.

What is cystic acne?

Cystic acne is a type of abscess that is formed when oil ducts become clogged and infected. Cystic acne affects deeper skin tissue than the more superficial inflammation from common acne. Cystic acne is most common on the face and typically occurs in the teenage years.

What is hidradenitis suppurativa?

Hidradenitis suppurativa is a condition in which there are multiple abscesses that form under the armpits and often in the groin area. These areas are a result of local inflammation of the sweat glands. This form of skin infection is difficult to treat with antibiotics alone and typically requires a surgical procedure to remove the involved sweat glands in order to stop the skin inflammation.

What is a pilonidal cyst?

A pilonidal cyst is a unique kind of abscess that occurs in or above the crease of the buttocks. Pilonidal cysts often begin as tiny areas of infection in the base of the area of skin from which hair grows (the hair follicle). With irritation from direct pressure, over time the inflamed area enlarges to become a firm, painful, tender nodule making it difficult to sit without discomfort. These frequently form after long trips that involve prolonged sitting.

Why do boils occur?

There are many causes of boils. Some boils can be caused by an ingrown hair. Others can form as the result of a splinter or other foreign material that has become lodged in the skin. Others boils, such as those of acne, are caused by plugged sweat glands that become infected.

What are additional causes of boils?

The skin is an essential part of our immune defense against materials and microbes that are foreign to our body. Any break in the skin, such as a cut or scrape, can develop into an abscess (boil) should it then become infected with bacteria.

Who is most likely to develop a boil?

Anyone can develop a boil. However, people with certain illnesses or medications that impair the body's immune system are more likely to develop boils. Among the illnesses that can be associated with impaired immune systems are diabetes and kidney failure. Diseases, such as hypogammaglobulinemia, that are associated with deficiencies in the normal immune system, can increase the tendency to develop boils. Many medications can suppress the normal immune system and increase the risk of developing boils. These medications include cortisone medications (prednisone and prednisolone) and medications used for cancer chemotherapy.

What is the treatment for a boil?

Most simple boils can be treated at home. Ideally, the treatment should begin as soon as a boil is noticed since early treatment may prevent later complications. The primary treatment for most boils is heat application, usually with hot soaks or hot packs. Heat application increases the circulation to the area and allows the body to better fight off the infection by bringing antibodies and white blood cells to the site of infection.

Should boils be drained?

As long as the boil is small and firm, opening the area and draining the boil is not helpful, even if the area is painful. However, once the boil becomes soft or "forms a head" (that is, a small pustule is noted in the boil), it can be ready to drain. Once drained, pain relief can be dramatic. Most small boils, such as those that form around hairs, drain on their own with soaking and/or heat application. On occasion, and especially with larger boils, the larger boil will need to be drained or "lanced" by a health-care practitioner. Frequently, these larger boils contain several pockets of pus that must be opened and drained.

Should boils be treated with antibiotics?

Antibiotics are often used to eliminate the accompanying bacterial infection. Especially if there is an infection of the surrounding skin, the doctor often prescribes antibiotics. However, antibiotics are not needed in every situation. In fact, antibiotics have difficulty penetrating the outer wall of an abscess and often will not cure an abscess without additional surgical drainage.

When should I seek medical attention?

You should call your doctor and seek medical attention if:

• the boil is located on your face, near your spine, or near your anus;
• a boil is getting larger;
• the pain is severe;
• you have a fever;
• the skin around the boil turns red or red streaks appear;
• you have a heart murmur, diabetes, any problem with your immune system, or use immune-suppressing drugs (for example, corticosteroids or chemotherapy) and you develop a boil;
• the boil has not improved after five to seven days of home treatment; or
• you get many boils over several months.

What can be done to prevent boils (abscesses)?

The regular use of antibacterial soaps can help to prevent bacteria from building up on the skin. This can reduce the chance for hair follicles to become infected and prevent the formation of boils. Your health-care practitioner may recommend special cleansers such as pHisoderm to further reduce the bacteria on the skin. When hair follicles on the back of the arms or around the thighs are continually inflamed, regular use of an abrasive brush (loofah brush) in the shower can be used to break up oil plugs and other buildup around hair follicles. Pilonidal cysts can be prevented by avoiding continuous direct pressure or irritation of the buttock area when a local hair follicle becomes inflamed. Regular soap and hot water cleaning and drying can be helpful. For acne and hidradenitis suppurativa, antibiotics may be required on a long-term basis to prevent recurrent abscess formation. Finally, surgery may occasionally be needed, especially for hidradenitis suppurativa or pilonidal cysts that recur.. For pilonidal cysts, surgically removing the outer shell of the cyst is important to clear the boil. For hidradenitis suppurativa, extensive involvement can require plastic surgery.

Related Reading Topics

• Boils
• Acne (Pimples)
• MRSA Infection (Methicillin-Resistant Staphylococcus Aureus)
• Staph Infection (Staphylococcus Aureus)
• Common Skin Rashes