Symptoms and Signs of Boils

Medical Author:
Medically Reviewed on 3/11/2019

Doctor's Notes on Boils

A boil is a skin abscess, which is a collection of pus within the skin. Furuncles, carbuncles, cystic acne, hidradenitis suppurativa, and pilonidal cyst are all among the different types of boils. Bacterial infection is the most common cause of boils.  Boils can occur anywhere on the body, including the trunk, armpit, extremities, groin, buttocks, or other areas.

A boil begins as a reddened, tender bump or lump. The lump becomes harder with time and increasingly tender. Eventually, the center of the boil softens and becomes filled with pus. The boil may spontaneously drain out through the surface of the skin, leading to symptoms such as draining or oozing pus. If the infection spreads beyond the site of the boil, associated symptoms can include redness, swelling, and warmth over the affected area of skin or soft tissue.

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Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.