A boil is a red, swollen, painful bump under the skin that is usually 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 chance of a boil include:
A boil may cause:
You will be asked 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:
The boil can be drained if needed. The infection can be treated 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 may 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 large, you may need to have it drained or lanced by your doctor. This is all most boils need to get better.
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 area heals completely. Try and keep the wound open by soaking or ointment to avoid it filling up with pus again.
Antibiotics may be needed if you have:
To help reduce your chances of a boil:
American Academy of Dermatology
Family Doctor—American Academy of Family Physicians
Public Health Agency of Canada
The College of Family Physicians of Canada
Acne. EBSCO DynaMed Plus website. Available at:http://www.dynamed.com/topics/dmp~AN~T115279/Acne. Updated June 27, 2017. Accessed August 17, 2017.
Boils. DermNet New Zealand website. Available at: https://www.dermnetnz.org/topics/boils. Updated January 2016. Accessed August 17, 2017.
Hidradenitis suppurativa. EBSCO DynaMed Plus website. Available at:http://www.dynamed.com/topics/dmp~AN~T115217/Hidradenitis-suppurativa. Updated August 9, 2016. Accessed August 17, 2017.
Nodulocystic acne. DermNet New Zealand website. Available at: https://www.dermnetnz.org/topics/nodulocystic-acne. Updated February 2014. Accessed August 17, 2017.
Pilonidal disease. EBSCO DynaMed Plus website. Available at:http://www.dynamed.com/topics/dmp~AN~T114205/Pilonidal-disease. Updated January 30, 2017. Accessed August 17, 2017.
Skin abscesses, furuncles, and carbuncles. EBSCO DynaMed Plus website. Available at:http://www.dynamed.com/topics/dmp~AN~T116747/Skin-abscesses-furuncles-and-carbuncles. Updated July 31, 2017. Accessed August 17, 2017.
Last reviewed September 2018 by EBSCO Medical Review Board Michael Woods, MD, FAAP Last Updated: 9/3/2014