What is a boil?

A boil, sometimes also referred to as a furuncle, is an infection involving a hair follicle on the skin. Boils are typically caused by Staphylococcus aureus bacteria, although they may be caused by other bacteria or fungi present on the skin surface. In addition to affecting the hair follicle, infections that cause boils will also typically involve the surrounding skin.

Boils form when bacteria from the skin surface infiltrate a hair follicle. This intrusion of bacteria triggers an immune response that includes drawing white blood cells into the infected follicle to fight the infection. If the infection in the follicle is not cleared quickly, pockets of bacteria, dead cells, and fluids can develop, resulting in the formation of a boil.

Boils may form individually or be grouped together. When multiple boils fuse together to become one lump, the resulting lump is called a carbuncle. Boils may occur anywhere on the body, although they are most commonly located in the armpits or on the buttocks, face, neck or thighs. Although there is no specific cause for the formation of boils, poor hygiene or conditions that weaken the immune system can lead to increased susceptibility.

Before boils can heal completely, they must open and drain. Boils typically resolve on their own within two weeks of onset.

Seek prompt medical care if a boil lasts for longer than two weeks, is recurrent, is located in the middle of the face or on the spine, or is accompanied by other symptoms, including a fever, an excessive amount of fluid around the boil, or the presence of red streaks coming from the boil.


What are the symptoms of a boil?

Boils exhibit multiple symptoms, including the formation of rigid, sensitive, swollen, bright red areas in the skin. Boils become more painful and less rigid as they develop. Typically, a boil should clear up in two weeks or less. If you have a boil that lasts for more than two weeks, contact your health care professional.

Common symptoms of boils

You may notice symptom... Read more about boilsymptoms


What causes a boil?

A boil develops when a hair follicle becomes infected by bacteria or fungus from the skin. The presence of infection draws in white blood cells from the body’s immune system to combat the infection. However, if the infection does not resolve quickly enough, pockets of bacteria, dead cells, and fluids can develop, resulting in the formation of a boil. Boils are very common and may be caused, in ... Read more about boilcauses


How is a boil treated?

Boils should heal on their own after several weeks, but will only do so after they are opened and drained. You should never attempt to force a boil to open or drain, since doing so could spread the infection. A boil that is especially deep or large may need to be treated by a health care professional.

Although a boil typically heals on its own within two weeks, the healing process... Read more about boiltreatments

Medical Reviewer: William C. Lloyd III, MD, FACS Last Annual Review Date: Aug 23, 2013 Copyright: © Copyright 2014 Health Grades, Inc. All rights reserved. May not be reproduced or reprinted without permission from Health Grades, Inc. Use of this information is governed by the HealthGrades User Agreement.

This Article is Filed Under: Skin, Hair and Nails

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