Boils and Carbuncles

What are Boils and Carbuncles?

A boil is an infected bump on your skin that is usually caused by friction in the hairy areas of your body, such as your armpits, thighs or buttocks. Sometimes boils can occur on the face or neck as well. A carbuncle is a group of boils that becomes interconnected and form a deeper infection.

Boils and carbuncles are often infected with the bacteria Staphylococcus aureus, which can enter the body through a cut or abrasion. However, other bacteria and fungi can infect the skin and cause a boil. Boils often form over hair follicles and cause infection throughout the follicle and deep into the skin.

People who come in contact with others who have a Staphylococcus aureus infection may be more likely to develop their own infection. People with skin conditions that cause wounds to the skin, like eczema or acne, are also at risk. Diabetics and others with compromised immunity may have more trouble fighting off bacteria and thus may be more likely to develop boils or carbuncles.

What are the Symptoms of Boils and Carbuncles?

You can identify a boil compared to any other lump or bump because it is swollen and painful. The lump extends deep into the skin and may have a “head” at the top that releases pus. A boil may also continuously weep clear or pus-like fluid. Boils that build up pus can swell to the size of a golf ball.

If a boil is untreated, it can spread infection to the surrounding skin and form a carbuncle. The symptoms are similar for a carbuncle, but you’ll see multiple lumps instead of just one. A carbuncle may also extend more deeply into the skin than a single boil.

Boils and Carbuncles Causes

Boils and carbuncles are usually caused by Staphylococcus aureus bacteria. Although this bacteria usually lives harmlessly on the skin, if it manages to get beneath the surface of the skin it can create an infection. In the case of boils, it is usually hair follicles which become infected, and this may occur when you sustain a cut or graze to the surface of the skin.

In an attempt to deal with the infection, the body sends increased white blood cells to the area in order to kill off the bacteria. However, eventually the boil will fill up with dead bacteria, skin cells and white blood cells to create pus. This buildup creates a great deal of pressure in the area, which is what causes pain.

Carbuncles occur as a result of having a cluster of boils. Multiple boils usually occur when the infection spreads underneath the skin.

How are Boils and Carbuncles Treated?

Small boils can be treated at home with clean, warm compresses several times a day to draw out the pus. Do not puncture the boil as that can spread infection to the surrounding skin. Larger boils should be treated by a doctor.

If you have a fever or your boil or carbuncle is in a particularly uncomfortable place, such as your spine or your buttocks, you should see a medical professional. You may be prescribed an antibacterial ointment or gel to apply to the boil.

Be careful to wash your hands frequently, and do not share clothing, bedding or towels with other people until the boil or carbuncle is fully healed. This prevents spreading the infection to others.

Boils and Carbuncles Prevention

To prevent boils and carbuncles, it’s important to minimize the risk of developing an infection beneath the skin. Washing skin regularly is vital, and a mild antibacterial soap may be particularly helpful to those who have had many boils in the past.

Any cuts, wounds or grazes to the skin should be carefully cleaned, no matter how small they are. Sterile bandages should then be used to reduce the risk of bacteria entering the wound before it heals over.

Boils and carbuncles can spread from one part of the body to another and from person to person via the bacteria in the pus. To avoid this, wash hands thoroughly after touching a boil or carbuncle and avoid sharing towels with an individual who has a boil.

To prevent a boil developing into a carbuncle, do not try squeezing it. Although it may be tempting to try to drain the pus yourself, you will risk bursting the boil underneath the skin which could spread the infection over a wider area and create multiple boils. If a boil is incredibly uncomfortable and doesn’t seem to be healing on its own, visit a doctor for professional treatment.

Last Reviewed:
September 13, 2016
Last Updated:
November 17, 2017