Boils are infected, pus-filled swellings in the skin that are often located in or near hair follicles. They are most often found on the back of the neck and in other moist areas of the body like the armpits and groin, but may be anywhere on the body. Sometimes several boils form close together in a cluster. A carbuncle is formed when several boils merge to form a single deep abscess with several heads or drainage points. An abscess may be so deep that it may not surface for a long time. Boils and carbuncles are firm reddish swellings about 5-10 mm across that are slightly raised above the skin surface. They are sore to the touch. A boil usually has a visible central core of pus; a carbuncle is larger and has several visible heads. Boils occur most commonly on the face, back of the neck, buttocks, upper legs and groin area, armpits, and upper torso.

Carbuncles are less common than single boils; they are most likely to form at the back of the neck and with Males. Carbuncles can form in the same areas as boils, and may also form on the scalp, face, and buttocks. Furunculosis is a word that is sometimes used to refer to recurrent boils. Many patients have repeated episodes of furunculosis that are difficult to treat because their nasal passages carry colonies of Staphylococcus aureus. These bacterial colonies make it easy for the patient's skin to be reinfected.

A milder version of boils is folliculitis. This is an infection of hair follicles, usually with Staph bacteria. These often itch more than hurt. The appearance is similar to acne pustules.

A boil starts out suddenly as an itchy, red, painful lump. Usually within 24 hours, the lump fills with pus and takes on a round appearance with a yellow-white tip. There may be swelling around the boil as well as swelling of any lymph nodes near the boil. Lymph nodes are located in the neck, armpit, and groin area.

Boils and carbuncles are more likely to develop in those with:

• Diabetes, especially when treated by injected insulin
• Alcoholism or drug abuse
• Poor personal hygiene
• Crowded living arrangements
• Jobs or hobbies that expose them to greasy or oily substances, especially petroleum products
• Allergies or immune system disorders, including HIV infection
• Family members with recurrent skin infections

Boils may take from 10 to 25 days to heal. In most cases, a boil will not heal until it bursts and drains. This can take as long as 5 to 7 days. A single boil can usually be cared for at home and does not require a trip to the doctor. Since releasing the pus in a boil can lead to more infection, puncturing it at home is not usually advised. If you do lance it, make sure to sterilize the surrounding area carefully before and after, washing the hands after touching the area.

If the boil bursts, apply an antibiotic ointment (like Bacitracin or Neosporin) or use Betadine to reduce the chance of infection. Keep the skin around it clean, and wash the hands carefully after touching the area.

You should see a doctor if:

a boil develops in a child or a sick or elderly person

a boil develops on the face near the eyes or nose

a boil becomes extremely large or painful

a cluster of boils form or you have an abscess

boils become increasingly common

red lines spread out from the center of the boil

the boil is extremely tender

fever and chills develop

lymph nodes begin to swell that are located in other areas of the body from where the original lymph node swelling occurred.

Medical treatment by a healthcare provider may include lancing or puncturing the boil to release the pressure and allow for drainage. Antibiotics may be prescribed to stop the infection.

Practicing good hygiene habits minimizes the frequency of recurring boils and prevents the spread of infection. This includes not picking at boils, using clean towels after each bath or shower, and cleaning the skin with an antiseptic soap like Betadine.

Hidradenitis Suppurativa is an uncommon disorder of unknown cause in which boil-like lumps develop in the groin and some times under the arms and under the breasts.