What are boils?

Boils (also called furuncles) are a deep infection of hair follicles.

Boils present as one or more tender red spots, lumps or pustules. Careful inspection reveals that the boil is centred on a hair follicle. A boil is a deep form of bacterial folliculitis; superficial folliculitis is sometimes present at the same time. Staphylococcus aureus can be cultured from the skin lesions.

If there are multiple heads, the lesion is called a 'carbuncle'. Large boils form abscesses, defined as an accumulation of pus within a cavity. Cellulitis may also occur, ie. infection of the surrounding tissues, and this may cause fever and illness.

Boils - Images copyright DermNet (NZ)

Why do boils occur?

Most people with boils are otherwise healthy and have good personal hygiene. They do, however, carry Staph. aureus on the surface of their skins (Staph. carrier state). Why this occurs is usually not known, but it is estimated that 10-20% of the population are Staph. carriers.

Staph. aureus is most commonly carried in the nostrils, armpits, between the legs and in the cleft between the buttocks. It may be transferred to other sites from the nostrils via the finger nails.

Tiny nicks or grazes or something rubbing against the skin can inoculate the Staph. germ into the wall of a hair follicle which is a 'weak point' in the skin's defences. Once inoculated, the bacteria cause a boil which goes on to run its usual course of about 10 days.

Although most people with boils are otherwise healthy, boils are sometimes related to immune deficiency, anaemia, diabetes or iron deficiency.

Treatment

General measures:

• Consult your doctor about your general health.
• If you are overweight, try to reduce your weight; take regular exercise.
• Follow a balanced healthy diet with meat, plenty of fruit and vegetables.
• Wash your whole body once a day with soap and water. Wash your hands several times daily.
• Don't share your flannel or towel with other family members.
• Maintain a clean handkerchief and don't pick your nose!
• Change your underclothes and night attire regularly.
• Avoid leisure activities which cause sweating and friction from clothing, such as squash and jogging.
• If you are iron deficient, a course of iron tablets may help reduce infection.
• 1000mg of vitamin C each day has also been advocated.

Skin cleansing regime - ask your doctor for specific advice.

Some suggestions:

• Use an antiseptic cleanser in your daily bath or shower for a week then twice weekly for several weeks. The cleanser may cause a little dryness.
• Your doctor may recommend an antiseptic or antibiotic ointment or gel to apply to the inside of the nostrils.
• Wipe the entire skin surface daily for a week with 70% isopropyl alcohol in water (this will make the skin dry).
• Apply a topical antiseptic such as povidone iodine or chlorhexidine cream to the boils and cover with a square of gauze.
• Your doctor may prescribe an oral antibiotic (usually the pencillin antibiotic flucloxacillin), sometimes for several weeks.
• Other members of the family with boils should also follow a skin cleansing regime. Your doctor may also advise the family to apply topical antibiotic to their nostrils in case they are Staph. aureus carriers as well.
• If the boils fail to clear up, a swab should be taken for microbiological culture, in case of methicillin resistant staphylococci.
• Sometimes, special antibiotics may be prescribed on the recommendation of a specialist, including fucidin, clindamycin, rifampicin and cephalosporins.

Original material provided by the New Zealand Dermatological Society Inc. (DermNet NZ), and reviewed by everybody, August 2005.