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 spreading infection.

What is the cause?

Boils commonly develop because bacteria have infected hair follicles, which are the small openings that hair grows from.

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, such as the nose, mouth, genitals, and rectum. The bacteria cause an infection only if they enter the skin through a scrape, irritation, or injury of some kind. Sometimes friction on the skin--from clothing, for example--will cause a hair follicle to swell up. This can make the opening close up, 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 as a red lump. Then, after a time, the lump fills with pus and develops a yellow-white tip. Pus or other fluid may drain from the boil. There may be swelling around the boil. The boil may hurt only when you touch it or it may be quite painful all of the time.

Lymph nodes near the boil may also swell. You are most likely to notice swollen lymph nodes in the neck, armpit, or groin area, depending on where the boil is.

Symptoms of carbuncles are similar but more severe than the symptoms caused by boils.

How are they diagnosed?

Your healthcare 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 make you more likely to have the sores, such as diabetes or kidney or liver disease.

How are they treated?

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

For treatment at home you can:

  • Wash your hands and then put a warm, moist cloth on the boil or carbuncle for 10 to 15 minutes at least 3 times a day. This helps the boil come to a head and drain on its own—the safe way to drain. Once the boil begins to drain, you will have less pressure and pain.
  • If the boil or carbuncle is in your groin or on your buttock you can soak in a tub of warm water for 10 to 15 minutes. Be sure to clean the tub well before and after soaking so that bacteria cannot be passed to others.
  • After soaking or using the moist cloth, clean the skin around the sore with water and antibacterial soap. Put a sterile gauze bandage over the area until it is healed. If drainage soaks through the bandage or the bandage gets wet or dirty, change it as soon as possible.
  • Take a pain reliever, such as acetaminophen.

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

Your healthcare 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. Opening a boil at home may cause spread of the infection into the bloodstream and cause serious medical problems.

Often draining the boil is the only treatment needed. However, if there is any sign that the bacteria may be spreading to other parts of your body, your provider will prescribe antibiotics.

If the boil is deep, your healthcare provider may need to keep the skin open after draining the boil. A small amount of slim gauze is usually used as loose packing in the wound. This ensures that the wound heals from the bottom up, preventing the skin from closing over the healing wound too early. Sometimes another boil will form in the same place right away if the skin is allowed to close before all the bacteria have been killed. You will need follow-up visits for gradual removal of the gauze as the wound heals.

If a boil doesn’t yet have a point or head on it, your provider may recommend taking an antibiotic to see if it will get rid of the boil without draining or opening of the boil.

If you have an underlying illness, such as diabetes, your healthcare provider will want you to schedule follow-up 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 healthcare provider. Depending on the severity of the problem and its treatment, the carbuncle should heal in 2 to 3 weeks after treatment.

Your healthcare 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 healthcare 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 coming back:

  • Do not open or squeeze the boil or carbuncle yourself. This can spread the infection.
  • If the boil opens or drains, clean it with an antiseptic soap. Cover it with a loose, gauze bandage. Change the bandage at least every day until the boil stops draining.
  • Wash your hands often with soap for at least 15 seconds. Always wash your hands 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.) You can also carry an alcohol-based hand cleaner to clean your hands when soap and water aren’t available.
  • Wash clothes that touch the infected area in hot, soapy water. Dry clothes on the hot setting if you use an automatic dryer.
  • Practice good personal hygiene. Bathe or shower daily.
  • Don’t share washcloths, towels, clothing, bath water, or razors. Sharing these items could spread the infection to others. Wash your hands well after caring for the boil.
  • Get treatment for any underlying illness or skin problem.

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