A boil is a red, swollen, painful bump under the skin that is caused by an infection. Boils often start in an infected hair follicle. Bacteria form an abscess or pocket of pus. With time, the pus may come to a head and drain out through the skin. Boils can occur anywhere, but common sites include the face, neck, armpits, buttocks, groin, and thighs.
There are several types of boils:
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Causes of boils may include:
Factors that increase your risk of getting a boil include:
Boils may cause:
The doctor will ask about your symptoms and medical history. A physical exam will be done. A bacterial culture of the boil may be taken.
Some boils do not need medical attention and may drain on their own. More serious symptoms from boils may require treatment. These include:
Your doctor can drain the boil if needed and treat the infection with antibiotics.
Home treatment may include:
Apply warm compresses to the boil for 20 minutes, 3-4 times a day. Depending on the area of the body affected, you may be able to soak the boil in warm water. These measures can ease the pain and help bring the pus to the surface. Repeated soaking will help the boil begin to drain.
Do not pop or lance the boil yourself. This can spread the infection and make it worse. If the boil does not drain on its own or it is very large, you may need to have it drained or lanced by your doctor.
Whether the boil drains on its own or was lanced by a doctor, you must keep it clean. Wash it with antibacterial soap and apply a medicated ointment and bandage. Clean the affected area 2-3 times a day until the wound heals completely.
To help prevent boils:
American Academy of Dermatology
American Academy of Family Physicians
The College of Family Physicians of Canada
Public Health Agency of Canada
Boils. DermNet NZ website. Available at: http://www.dermnetnz.org/bacterial/boils.html . Accessed September 11, 2013.
Skin abscess. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed.ebscohost.com/about/about-us . Updated May 20, 2013. Accessed September 11, 2013.
Last reviewed September 2013 by Michael Woods, MD
Last Updated: 9/30/2013