Boils and carbuncles are painful lumps on the skin. They are usually caused by a bacterial infection.
Symptoms of boils
A boil is a lump that can develop anywhere on your skin.
Boils can look:
- red on white skin
- brown, purple or grey on black or brown skin
You're most likely to get a boil in an area where you have hair, sweat and friction. Common areas to get boils include the neck, face and thighs.
When pus forms inside the boil, it becomes bigger and more painful. Most boils burst and heal within a few weeks. They do not usually leave a scar.
You may be more likely to get boils if you have a condition that affects your immune system, such as diabetes or HIV. Boils are also more common in males.
It can sometimes be difficult to tell the difference between a boil and a spot. Boils tend to grow bigger and become more painful. Your GP can diagnose a boil from its appearance.
Symptoms of carbuncles
A carbuncle is a cluster of boils that usually develops over a few days.
Common areas to get carbuncles include the back, thighs or back of the neck.
You may also:
- have a high temperature of 38 degrees Celsius or above
- feel generally unwell
- feel weak and exhausted
Carbuncles are less common than boils.
Carbuncles happen most in:
- middle-aged and older men
- people with a weak immune system
Causes of boils and carbuncles
Boils and carbuncles are often caused by bacteria called Staphylococcus aureus (staph bacteria). The bacteria infect hair follicles. Staph bacteria can live on the surface of the skin or in the lining of the nose without causing harm.
You can get a boil when bacteria enter the skin through cuts and grazes. Your immune system sends white blood cells to kill the bacteria.
Over time, pus forms inside the boil. Pus is a build-up of dead white blood cells, skin cells and bacteria.
A carbuncle develops when the infection spreads further beneath the skin.
Preventing boils and carbuncles
You cannot always avoid getting a boil or carbuncle. There are things you can do to reduce your risk.
Do
-
wash your skin regularly using a mild antibacterial soap
-
clean any cuts, wounds or grazes - even small ones
-
cover cuts, wounds and grazes with a sterile bandage until they heal
-
eat well and exercise regularly to boost your immune system
How boils and carbuncles spread
Boils and carbuncles can spread to another part of the body or to another person. There are things you can do to stop them spreading.
Do
-
wash your hands after touching affected areas
-
use a separate face cloth and towel
-
wash underwear, bed linen and towels at a high temperature
-
cover wounds with a dressing until they heal
-
put used dressings in the bin straight away
When to see your GP
Most boils burst and heal by themselves. Your GP can diagnose a boil or carbuncle by looking at it.
Non-urgent advice: Contact a GP if
you have a:
- carbuncle
- boil on your face or spine
- boil that keeps getting bigger and feels soft and spongy to touch
- boil that does not heal in 2 weeks
- boil and a high temperature
- boil or carbuncle and you have diabetes
Further tests
You may need further tests if you have:
- a boil or carbuncle that does not respond to treatment or comes back
- many boils or carbuncles
- a boil or carbuncle and a weak immune system - for example, if you are having chemotherapy
Further tests can include a blood test or skin swab.
Content supplied by the NHS and adapted for Ireland by the HSE
