A boil is a skin infection that is usually caused by the bacteria Staphylococcus aureus (staph). A carbuncle is a group of boils located in one area of the body. If left alone, a boil will break and drain on its own over time. In certain cases, a doctor may need to cut into your skin to drain the pus.
A boil (or furuncle) is a pus-filled bump that develops in your skin. Carbuncles are clusters of several boils. Boils usually begin as red bumps, which quickly increase in size and fill with pus. Boils are usually caused by the bacteria Staphylococcus aureus (staph infection).
These painful skin abscesses result from bacteria infecting a hair follicle. They commonly occur on the face, neck, armpits, buttocks, and thighs, but can appear anywhere on your body.
Many boils get better with at-home treatments such as warm compresses. Larger boils may require treatment by a healthcare professional.
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A boil develops over a few hours or days. It usually starts out as a tender, swollen red bump. It may feel warm to the touch. As the boil develops, it:
Carbuncles are formed when multiple boils cluster together and form an area of infection. In addition to the symptoms seen with boils, carbuncles may also be associated with fever, chills and fatigue.
Boils are usually caused by the bacteria Staphylococcus aureus (staph infection), but other bacteria and fungi can cause them too. Bacteria enter your skin through a cut or a hair follicle (the opening in your skin where hair grows out). Your body’s immune system responds by sending infection-fighting white blood cells to the area. The white blood cells build up, along with damaged skin, to form pus. Carbuncles develop when more than one hair follicle gets infected. The infection is deeper and more severe than one boil.
Anyone can develop a boil, but certain factors can increase your risk. These risk factors include:
A boil or carbuncle should never be squeezed or pricked with a pin or sharp object to release the pus and fluid. This can spread the infection to other parts of your skin.
If left alone, a boil will break and drain on its own over time. In certain cases, a doctor may need to cut into your skin to drain the pus. Once the fluid and pus drain from the boil or carbuncle, it will heal. The doctor may also prescribe antibiotics if there is a serious infection.
If you have a boil, you can do the following:
If you have a fever or other serious symptoms with the boil, see your doctor. Patients who have diabetes or who have a condition that affects the immune system should see a doctor for the treatment of the boil.
A boil or carbuncle can happen despite the best hygiene. However, you can prevent boils if you:
Most boils heal and clear up in about two to three weeks. Boils don’t usually cause serious or long-term health problems. If your provider drained the pus, you may have a small scar. Severe carbuncles can leave scars after they heal.
For some people (especially people with a weakened immune system), boils and carbuncles come back in the same area or never completely go away. Recurrent boils can be a sign of a life-threatening infection called methicillin-resistant staphylococcus aureus (MRSA). Rarely, bacteria from a boil can:
If you have a carbuncle:
A note from Cleveland Clinic
Boils are painful and unsightly, but they rarely cause serious health problems. Many boils heal with home treatments like warm compresses and over-the-counter pain relievers. But it’s a good idea to call your provider if you have signs of a boil, especially if it’s painful. Your provider will monitor you to ensure the infection doesn’t spread or worsen, and will provide treatment if necessary. To reduce your risk of developing a boil, keep your hands clean, bathe regularly and maintain good overall health.
Last reviewed by a Cleveland Clinic medical professional on 10/11/2021.
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