Boils and Carbuncles

What are boils and carbuncles?

A boil is a type of infected sore on the skin. The sore is raised, red, painful, and filled with pus. A carbuncle is a large severe boil or group of boils that develop close together due to the spread of the infection.

How do they occur?

Boils commonly develop because bacteria have infected hair follicles (the small openings out of which hair grows).

Staphylococcus aureus ("staph") is the name of the bacteria that usually infect hair follicles. The bacteria normally live on the skin, particularly on certain parts of the body (rectum, nose, mouth, and genitals). The bacteria cause an infection only if they penetrate the skin through a scrape, irritation, or injury of some kind. Sometimes friction (from clothing, for example) will cause a hair follicle to swell up. The opening becomes closed, trapping the bacteria inside and starting an infection.

Boils and carbuncles often form in moist areas of the body such as the back of the neck, buttocks, thighs, groin, and armpits.

If you have a chronic illness, such as diabetes or kidney or liver disease, you may be more likely to have boils and carbuncles.

What are the symptoms?

A boil starts out suddenly as a 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. (You are most likely to notice swollen lymph nodes in the neck, armpit, or groin area.) The boil may be tender to touch or quite painful.

Symptoms of carbuncles are similar but more severe than those of boils.

How are they diagnosed?

Your health care provider will examine the infected area. Tell your provider if you have had a boil or carbuncle longer than 2 weeks or if you have boils often.

If you have boils often, you may have lab tests of your blood or urine. These tests can check for conditions that might cause the sores, such as diabetes mellitus or kidney or liver disease.

How is it treated?

A boil can sometimes be treated at home, but a carbuncle often needs medical treatment.

For treatment at home you can:

• Put a warm, moist cloth on the boil or carbuncle for 10 to 15 minutes at least 3 times a day.
• Clean the sore with antiseptic soap and protect it with a loose gauze dressing until it has healed.
• Take acetaminophen or another pain reliever.

These steps will help relieve the pain, reduce the risk of spreading the infection, and help boils to heal.

See your health care provider if:

• A boil does not drain and heal with treatment at home.
• The boil lasts longer than 1 week.
• The boil becomes very large or painful.
• You are an adult over the age of 65 or you have diabetes.
• You have a boil on your face or near your eyes or nose.
• You have a cluster of boils or they become increasingly more common.

Your health care provider may recommend that you take antibiotic drugs to heal the infection. Your provider may drain the boil or carbuncle by opening it with a sterile needle or scalpel. After the sore has been opened, it should be covered with a loose, gauze dressing until it heals. (Do not try to open a boil at home. This may cause harmful spread of the infection.)

If you have an underlying illness, such as diabetes, your health care provider will want you to schedule regular appointments so your condition can be monitored. If your boil or carbuncle does not heal properly or if new symptoms develop, contact your provider.

How long will the effects last?

Boils may take from 1 to 3 weeks to heal. In most cases, a boil will not heal until it opens and drains. This can take up to a week.

A carbuncle often requires treatment by your health care provider. Depending on the severity of the problem and its treatment, the carbuncle should heal in 2 to 3 weeks after treatment.

Your health care provider may want to see you for a follow-up visit if he or she prescribes medicine to treat the infection, such as antibiotics, or treats it by opening the boil.

How can I take care of myself?

Be sure to follow the instructions your health care provider gives you. Take any prescribed medicine as directed.

What can I do to help prevent boils and carbuncles?

To help prevent boils and carbuncles from spreading and recurring:

• Do not open or squeeze the boil yourself. This can cause the infection to spread.
• If the boil does open or drain, clean it with an antiseptic soap. Cover it with a loose, gauze dressing. Change the dressing at least every day until the boil stops draining.
• Wash clothes that touch the infected area in hot, soapy water on a daily basis. Dry clothes on the hot setting if you use an automatic dryer.
• Practice good personal hygiene. Bathe or shower daily.
• Wash your hands often. Always wash them after caring for the boil, after using the bathroom, and especially before touching any food. (The bacteria that cause boils can also cause food poisoning.)
• Get treatment for any underlying illness.