A boil (furuncle) is an infection of a hair follicle. A carbuncle occurs when a group of hair follicles next to each other become infected. It is like a multiple boil. Chronic furunculosis is a condition where you have crops of boils that occur over a longer period of time.
Small boils are very common and often go away without any treatment. But they can be irritating and can also cause distress if they are in a prominent position such as on your face. Larger boils usually need treatment. If you get lots of boils that keep coming or don't go away then you may need some tests to check if there is any underlying cause.
Who gets them?
A boil looks like a small red lump on the skin that is tender. The surrounding skin may be swollen and inflamed. Thick, infected fluid called pus fills the centre of the boil. Boils can develop in any hairy area of skin. In particular, in sites where there is friction, or where the skin is sweaty. For example, they can appear on the neck, face, armpits, arms, buttocks and around the back passage (anus). A boil in the ear canal may be very painful. Carbuncles most commonly develop on the back of the neck or on the thighs.
A boil or carbuncle can occur in anyone at any age. However, they are uncommon in children and most common in teenagers and young adults. You have a higher risk of developing a boil or carbuncle if you:
- Have other skin conditions that may cause you to scratch and damage the skin - for example, eczema or scabies.
- Are very overweight (obese).
- Have a poor defence against infections (immune system).
- Have an illness making you frail or generally unwell.
- Are a carrier of staphylococcal germs (bacteria).
Did you find this information useful?
- Boils, carbuncles, and staphylococcal carriage; NICE CKS, July 2015 (UK access only)
- Bernard P; Management of common bacterial infections of the skin. Curr Opin Infect Dis. 2008 Apr 21(2):122-8. doi: 10.1097/QCO.0b013e3282f44c63.
- Shallcross LJ, Hayward AC, Johnson AM, et al; Incidence and recurrence of boils and abscesses within the first year: a cohort study in UK primary care. Br J Gen Pract. 2015 Oct 65(639):e668-76. doi: 10.3399/bjgp15X686929.
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