A boil is an infection of a hair follicle, caused by the bacterium Staphylococcus aureus. A boil on the eyelid is a stye. Severe or recurring cases may require medical treatment. Regular outbreaks may indicate other illnesses, including diabetes.
A boil, or furuncle, is an infection of a hair follicle caused by the bacterium Staphylococcus aureus (S. aureus). This common bacterium inhabits the skin, and approximately one third of the population carry the germ in their noses. S. aureus is usually harmless, but it can cause a range of mild to severe infections, if it gains access to deeper tissues. Certain areas of the body are more susceptible to boils, including the face, throat, armpits, groin and buttocks. A boil on the eyelid is known as a stye. A carbuncle is an aggregate of connected furuncles and has several pustular openings. Boils usually resolve by themselves, but severe or recurring cases require medical treatment. Options include lancing and draining the boil, and antibiotics.
Symptoms of boils
The evolution of a boil includes:
- A small area of skin becomes inflamed and tender
- A painful lump appears
- After a few days, a white or yellow head forms
- The boil bursts
- The pus drains out
- The site heals
- A scar may form, depending on the severity of the boil.
Risk factors for boils
Cuts, abrasions or scratches allow the bacteria to gain access to deeper tissues. Certain factors make a person more susceptible to outbreaks of boils, including:
- Diabetes – recurring boils may be symptomatic of uncontrolled diabetes, especially for people aged over 40 years.
- Poor hygiene – sweat and dead skin cells in natural creases and crevices, such as the armpit, provide a hospitable home for bacteria.
- Nutrition – inadequate nutrition may reduce a person’s natural immunity.
- Broken skin – other skin conditions, such as eczema, can break the skin surface.
Staphylococcus bacteria can cause a range of infections, from relatively mild to severe and life threatening. There is a small risk that bacteria may spread from the boil to other areas of the body. Infection can cause inflammation of many organs and tissues, including:
- Bone (osteomyelitis)
- Heart (endocarditis)
- Lung (pneumonia)
- Meninges, the membranes lining the central nervous system (meningitis)
- Skin (impetigo)
- Vein (septic phlebitis).
Suggestions for treating a boil include:
- Resist the temptation to squeeze the boil.
- Wash the boil with antiseptic soap.
- Apply a hot compress for 10 minutes or so, three times daily, to encourage the boil to come to a head.
- Cover a burst boil with a bandaid.
- Wash your hands thoroughly to prevent the spread of infection.
- Use fresh towels every time you wash and dry the infected areas.
- See your doctor if the boil isn’t improving after a few days.
Treatment for boils
Medical treatment for a severe boil may include antibiotics and lancing. Boils around the eyes and nose should always be treated by a doctor, because the infection may access the bloodstream and reach the brain. Furunculosis refers to recurring outbreaks of boils. Treatment includes:
- Checking for underlying disorders, such as diabetes.
- Long term use of antibiotics to rid the body of infection.
- Use of antiseptic shampoos and soaps.
- Antibiotic creams applied to the nasal membranes, because S. aureus commonly inhabits the nose.
- Strict attention to personal hygiene.
- Frequent laundering of all bedding and towels.
- In some cases, other members of the household will need similar treatment, since S. aureus is contagious.
Where to get help
- Your doctor
Things to remember
- A boil is an infection of a hair follicle, caused by the bacterium Staphylococcus aureus.
- Boils usually resolve by themselves, but severe or recurring cases require medical attention.
- Medical treatment may include antibiotics and lancing.
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North East Valley Division of General Practice
Last reviewed: October 2012
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