(Carbuncle; Furuncle; Cutaneous Abscess; Skin Abscess; Abscess, Cutaneous; Abscess, Skin)
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. Eventually, 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:
- Furuncle or carbuncle—an abscess caused by the bacteria Staphylococcus aureus or Streptococcus pyogenes, sometimes occurs as several boils in a group
- Pilonidal cyst—an abscess that occurs in the crease of the buttocks almost always require medical intervention
- Cystic acne—an abscess that occurs when oil ducts become clogged and infected, more common in the teenage years
- Hidradenitis suppurativa—an uncommon disorder where multiple abscesses occur in the armpit and groin area
Causes of boils may include:
- Bacteria, including Staphylococcus aureus
- Ingrown hair
- Splinter or foreign objected lodged in the skin
- Plugged sweat gland or oil duct
Factors that increase your chance of developing a boil include:
- Poor nutrition
- Poor hygiene
- Weakened immune system
- Exposure to harsh chemicals
Symptoms may include:
- Skin lump or bump that is red, swollen, and tender
- Lump becomes larger, more painful, and softer over time
- Pocket of pus may form on top of the boil (called "coming to a head")
The doctor will ask about your symptoms and medical history. A physical exam will be performed. 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 associated with boils that may require medical attention include:
- The boil worsens, persists, or becomes large or severe
- You have a fever
- The skin around the boil turns red or red streaks appear
- The boil does not drain
- An additional boil or boils appear
- The boil limits your normal activities
- The boil is on your face, near your spine, or in the anal area
- You have diabetes
- You develop many boils over several months
Your doctor can drain the boil if necessary 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. Once the boil comes to a head, repeated soakings will help the boil begin to drain.
Lancing the Boil
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.
Cleaning and Bandaging
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.
The College of Family Physicians of Canada
Public Health Agency of Canada
American Academy of Dermatology website. Available at: http://www.aad.org . Accessed October 13, 2005.
Hidradenitis Suppurativa. National Institute of Health Library website. Available at:
Last reviewed November 2008 by
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.
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