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:
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 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 large, you may need to have it drained or lanced by your doctor.
To help reduce your chance 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 August 26, 2016. Accessed September 29, 2016.
Boils. DermNet NZ website. Available at: http://www.dermnetnz.org/bacterial/boils.html. Updated June 2014. Accessed August 5, 2015.
Hidradenitis suppurativa. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T115217/Hidradenitis-suppurativa. Updated August 9, 2016. Accessed September 29, 2016.
Nodulocystic acne. DermNet NZ website. Available at: http://www.dermnetnz.org/acne/nodulocystic-acne.html. Updated February 2014. Accessed August 5, 2015.
Pilonidal disease. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T114205/Pilonidal-disease. Updated February 18, 2015. Accessed September 29, 2016.
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 August 4, 2015. Accessed September 29, 2016.
Last reviewed September 2016 by Michael Woods, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.