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Patient Information Leaflets (PILs)


What are the aims of this leaflet?

This leaflet has been written to help you understand more about boils (furuncles). It tells you what they are, what causes them, what can be done about them, and where you can find out more about them. 

What are boils?

A boil, or furuncle, is an abscess (infection) of the skin that starts in the deep part of the hair follicle.  The infection is usually caused by a bacterium called Staphylococcus aureus (S. aureus)Occasionally the infection may spread into the surrounding tissues (cellulitis) and can cause fever and a feeling of being unwell.  When several boils form close together and join beneath the skin, it is known as a carbuncle.  Sometimes rarer strains of S. aureus: Methicillin resistant Staphylococcus aureus (MRSA) and Panton-Valentine leukocidin (PVL), can give rise to boils.  The latter may cause boils which are larger and more painful (see Patient Information Leaflet on PVL Staphylococcus Aureus (PVL-SA) skin infection).

The bacteria causing the boil can occasionally spread from one part of the body to another and from one person to another by skin-to-skin contact and contaminated clothing and towels.  This is especially true when boils are caused by the PVL strain of S. aureus bacteria.  Boils are common in adolescents and can affect boys more often than girls. Sufferers of boils seldom have a problem with their immune system, but boils can be more severe in patients with a suppressed immune system.  Boils are more common in patients with diabetes and those who are overweight. 

What do boils look like?

Boils may be single or multiple.  A boil often starts as an itchy or tender spot that grows over a few days into a large firm red lump that can become increasingly painful and tender. Boils often develop around the neck, trunk and on the buttocks. Boils inside the nose or ear can be particularly uncomfortable.

As the lump continues to grow the centre of the abscess eventually softens and becomes filled with pus (white blood cells sent via the bloodstream to kill the infection). The pus may then burst through the surface of the skin, releasing the pus, or it may settle gradually without bursting.  

A healed boil tends to leave a red mark, which slowly fades but can leave a small scar.

How are boils diagnosed?

Boils are usually easy to diagnose by their appearance. If a boil contains pus, this can be swabbed and sent to the laboratory to check which bacteria is causing the boil and which antibiotics are suitable to treat it.

Can boils be cured?

Yes, infections settle with treatment.

S. aureus survives well in moist areas such as the nostrils, armpits, buttocks and groin. Some people carry S. aureus at these sites on a long-term basis; they are referred to as 'carriers'.  This is not usually a problem, however, if repeated infection of furuncles occur, it is wise to treat these areas (see below).

How can boils be treated?

As soon as the boil appears a hot compress applied to the area for 10-20 minutes several times a day may encourage maturation, drainage and resolution of symptoms.  A single boil usually settles naturally, especially if the pus it contains discharges spontaneously. However, with a larger boil your doctor may release the pus by cutting carefully into the boil (lancing) using sterile instruments.   An antibiotic cream or ointment can be used around the boil to stop others appearing nearby. Often an antibiotic is given by mouth as well, to make sure that the infection clears.

How do I stop the bacteria from spreading?

  • Your doctor may prescribe a topical treatment such as an antibacterial soap to wash with.  Sometimes an antibacterial nasal ointment is recommended to be applied into each nostril for 5-7 days.  Family members may also have to use this treatment if they are found to be asymptomatic carriers.
  • Change towels every day and do not share them with anybody else. Use a hot wash and hot tumble dry if possible to wash towels and bed linen.
  • Change bed sheets daily.
  • Keep the house clean, especially the sink, shower or bath.

You should seek medical advice if you are not sure of the diagnosis or if you feel unwell. You should also see your doctor if the problem persists or if you have recurring boils.

Self care (What can I do?)

  • Follow the measures outlined above to reduce the spread of boils.
  • Bath or shower daily, and keep your hands and nails clean. Avoid picking any sores.
  • Being overweight encourages boils, as the bacteria survive in folds of the skin, therefore weight loss if necessary may help prevent recurrence.
  • Avoid close contact with others and contact sports, such as rugby and judo, until the boils have cleared to reduce the risk of passing the infection onto others. Do not visit a swimming pool or a gym until they have cleared up.

Where can I get more information?

Web links to detailed leaflets:   

For details of source materials used please contact the Clinical Standards Unit (

This leaflet aims to provide accurate information about the subject and is a consensus of the views held by representatives of the British Association of Dermatologists: individual patient circumstances may differ, which might alter both the advice and course of therapy given to you by your doctor.

This leaflet has been assessed for readability by the British Association of Dermatologists’ Patient Information Lay Review Panel


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