Ask the Expert: Boils and Carbuncles

Ask The Expert 

What is it?

Boils and carbuncles are skin infections usually caused by staph aureus bacteria (staph).  These staph infections form pockets in the skin that are filled with pus, a fluid that includes bacteria, dead skin cells and infection-fighting white blood cells.  Whether the pocket of pus is called a boil or a carbuncle depends on its location and size:

• A boil, also called a furuncle, begins as a painful infection of a single hair follicle.  Boils can grow to be larger than a golf ball, and may commonly occur on the buttocks, face, neck, armpits and groin. 

• A carbuncle is a deeper skin infection that involves a group of infected hair follicles in one skin location.  They are often found on the back of the neck, shoulders, hips and thighs, and they are especially common in middle-aged or elderly men.  People with diabetes are more likely to develop them.

What are the symptoms?

A boil looks like a red, swollen, painful bump under the skin.  As the infection gets worse, a whitish tip, also called a point or head, can appear at the center of the boil.  This tip is usually the area from which the boil's pus will drain.  A carbuncle looks like a cluster of boils that are side-by-side and touching.

Whenever you have a boil or a carbuncle, you also can have a fever and feel generally sick.  A fever is more likely with a carbuncle than with a single boil.

How are they diagnosed?

Your health care provider can diagnose a boil or carbuncle by examining your skin.  If you get several boils within a short period of time, your health care provider may do blood tests to check for diabetes or other medical conditions that can increase your risk of repeated infections.

How long do they last?

In healthy people, a small boil will form a white tip (come to a head) and drain within 5 to 7 days.  However, very large boils or carbuncles can last longer and may not drain on their own.  These may need to be drained by a physician, and you may need to take antibiotics.

How do I prevent them?

If you have an area of skin that keeps getting them, keep the area clean and dry, and avoid wearing tight clothing that doesn't allow the skin to breathe.  Washing daily with antibacterial soap also can help.  At the 1st sign of irritation or a bump at a hair follicle, use warm soaks to open up the blocked pore and drain any early infection.  If you get signs of infection or redness with pain at a hair follicle as a result of shaving, you should avoid shaving in that area to prevent bacteria from being spread to other parts of the skin.

What is the treatment?

Small boils can be treated with moist heat (usually a warm, wet washcloth) applied for 20 to 30 minutes, 3 or 4 times a day.  This will help the boil drain on its own.  Once the boil drains, cover it with a clean bandage to protect the skin and absorb draining pus.  Wash the area daily with antibacterial soap to prevent the infection from spreading.  Anyone who helps care for the area should also wash his or her hands thoroughly with antibacterial soap.

Large boils and carbuncles may be treated with antibiotics.  Sometimes, the health care provider will drain the area through a small incision.  This will relieve pain, speed recovery and limit scarring.  If the infection is completely drained, antibiotics may not be necessary.  If the infection is deep, your health care provider may fill the empty pocket that contained the pus with a strip or piece of sterile gauze.  The gauze can keep the incision open, which will allow pus to continue to drain.  The pocket can then heal slowly, becoming more shallow over time until it is a on top of the skin.  You may need to return to your health care provider a few times to have the gauze and dressing changed.

When should I call my health care provider?

Call whenever you have a carbuncle, a large boil or a boil that doesn't improve after a week of home treatment as mentioned above.  If you have diabetes, you should call even if you develop a small boil because you are more prone to getting serious infections.  Ask to been seen right away if a boil of any size:

• Develops in an infant

• Is located on the face, rectum, groin or spine

• Produces fever or severe pain

• Interferes with movement

• Causes swelling, red streaks or other discoloration in nearby skin

If you have been treated with antibiotics and your infection does not appear to be getting better within 1 or 2 days, call your health care provider right away.  Your infection may be caused by a type of bacteria the antibiotic doesn't work on (resistant bacteria).  This bacteria is called MRSA.  To treat this type of infection, your health care provider needs to know that your 1st antibiotic didn't help.  You may need to take a different kind of antibiotic.

If you have had several episodes of boils within a short period of time, visit your health care provider.  He or she can check whether you have a medical illness you are unaware of that may be affecting your body's ability to fight infections.

What is the prognosis?

Most small boils heal without leaving a scar.  Generally, the larger the boil or carbuncle, the greater the chance it will leave a scar.  Because of this, you should see a health care provider if you have a boil on your face.  Antibiotic treatment and surgical drainage can help limit scar formation.

Diana Jones, is a OB/GYN and Women’s Health Nurse Practitioner at the BSU Women’s Center, managed by Cardinal Health System. For more information contact info@chsmail.org.  

Ask the Expert

Diana Jones, RNC, MSN, WHNP

Women's Health Nurse Practitioner

BSU Women's Center