Boils
Painful, pus-filled bumps from an infected hair follicle
Quick Facts
- Type: Bacterial skin infection
- Common cause: Staph bacteria infecting a hair follicle
- Common sites: Face, neck, armpits, buttocks, thighs
- See a doctor if: Fever, spreading redness, or no improvement
Overview
A boil is a painful, pus-filled lump that forms under the skin when a hair follicle or oil gland becomes infected, usually by bacteria such as Staphylococcus aureus (staph). It starts as a tender red bump and gradually fills with pus, becoming larger and more painful before it often comes to a head and drains.
Boils are very common and most are minor, clearing up on their own or with simple home care. A cluster of boils that join together under the skin is called a carbuncle, which is larger and more serious. While most boils heal without problems, some need medical treatment, especially if they are large, recur, or are accompanied by fever or spreading redness.
Symptoms
A boil typically develops in stages, with these features:
- A red, tender, firm lump that starts small and grows over days
- Increasing pain as it fills with pus
- A white or yellow center (head) as it comes to a point
- Swelling and redness of the surrounding skin
- Drainage of pus when it bursts or is drained
Larger boils or carbuncles can cause fever, tiredness, and a general feeling of being unwell. Spreading redness, red streaks running from the boil, increasing pain, or fever can signal a more serious or spreading infection that needs medical attention.
Causes
Boils are caused by bacteria, most often staph, that enter the skin and infect a hair follicle or oil gland. The bacteria commonly live harmlessly on the skin and in the nose, and cause a boil when they get into the skin through:
- A small cut, scratch, or insect bite
- Friction or irritation, such as from tight clothing or shaving
- Blocked or inflamed hair follicles
The body sends infection-fighting cells to the area, and the resulting mix of bacteria, dead cells, and tissue forms pus. Anyone can get a boil, but certain conditions and habits make them more likely.
Risk Factors
- Close contact with someone who has a boil or carries staph bacteria
- Diabetes or a weakened immune system
- Skin conditions such as eczema that break the skin barrier
- Poor hygiene or shared items like razors and towels
- Friction from clothing, shaving, or sweating
- Obesity
Diagnosis
Boils are usually diagnosed simply by examining the skin. Additional steps may be taken in certain situations:
- Examination: A doctor recognizes a boil by its appearance, tenderness, and pus.
- Pus culture: If a boil is severe, recurs, or does not respond to treatment, a sample of pus may be tested to identify the bacteria and which antibiotics will work.
- Underlying checks: Recurrent boils may prompt testing for conditions such as diabetes.
Treatment
Many small boils improve with simple home care, while larger ones need medical treatment.
- Warm compresses: Applying a warm, moist cloth several times a day helps a boil come to a head, drain, and relieve pain.
- Keeping it clean: Wash gently, cover with a clean dressing, and wash hands after contact.
- Do not squeeze: Squeezing or pricking a boil yourself can push the infection deeper and spread it.
- Medical drainage: A doctor can safely lance and drain a large or stubborn boil.
- Antibiotics: Prescribed for large or recurrent boils, carbuncles, or when there is surrounding infection or fever.
Most boils heal within a couple of weeks once they drain. Recurring boils may need a treatment plan to reduce bacteria on the skin.
Prevention
You can lower the chance of boils with good skin hygiene and care:
- Wash regularly and keep cuts and scrapes clean and covered
- Do not share towels, razors, or clothing
- Wash hands often, especially after touching a boil
- Avoid tight clothing that causes friction and sweating
- Manage conditions such as diabetes that raise the risk
When to See a Doctor
See a doctor if a boil:
- Is on the face, spine, or in a sensitive area
- Is very large, very painful, or does not improve after a week or two
- Comes back repeatedly or appears in clusters (a carbuncle)
- Is accompanied by fever, spreading redness, or red streaks
Spreading redness, red streaks, fever, or feeling very unwell can indicate a more serious infection. Seek prompt medical care, and urgent care if you feel very ill, as a spreading skin infection sometimes needs immediate treatment.
Frequently Asked Questions
Should I pop a boil at home?
No. Squeezing or pricking a boil yourself can push the infection deeper and spread it. Instead, apply warm compresses to help it drain on its own, and see a doctor if it is large, very painful, or does not improve.
How long does a boil take to heal?
Most boils come to a head and drain within about a week or two, then heal over the following days. Warm compresses speed this along. A boil that is not improving, is very large, or keeps recurring should be checked by a doctor.
Are boils contagious?
The bacteria that cause boils, often staph, can spread to other people and to other areas of your own skin through contact, shared towels, or razors. Washing hands, keeping the boil covered, and not sharing personal items help prevent spread.
When is a boil an emergency?
Seek prompt medical care if a boil is accompanied by fever, spreading redness, red streaks running from it, or if you feel very unwell, as these can indicate a serious spreading infection. Boils on the face or spine also warrant a doctor's attention.
Why do I keep getting boils?
Recurrent boils can result from carrying staph bacteria on the skin or in the nose, friction, or conditions such as diabetes or a weakened immune system. A doctor can suggest a plan to reduce bacteria and check for any underlying cause.
References
- Mayo Clinic. Boils and carbuncles.
- MedlinePlus, U.S. National Library of Medicine. Boils.
- Centers for Disease Control and Prevention (CDC). Staphylococcus aureus.
- American Academy of Dermatology Association. Boils: Diagnosis and treatment.