abscess, localized inflamation associated with tissue necrosis. Abscesses are characterized by inflamation, which is due to the accumulation of pus in the local tissues, and often painful swelling. They occur in the skin, at the root of a tooth, in the middle ear, on the eyelid (see sty), in the mammary glands, in the recto-anal area, and elsewhere in the body. Abscesses may develop in lung tissue, in the lymph nodes, and in bone. A sinus abscess may result in a fistula, and abscess of the appendix in appendicitis. Unless an abscess discharges spontaneously, surgical incision and drainage is required. See boil; carbuncle.

Localized collection of pus in a cavity in the deeper layers of the skin or within the body, formed from tissues broken down by white blood cells (leukocytes) in response to inflammation caused by bacteria. A wall develops, separating the thick yellowish pus from the extracellular fluid of nearby healthy tissues. Rupture of the abscess allows the pus to escape and relieves swelling and pain. Treatment consists of cutting into the wall to drain the pus and giving antibiotics. If infective contents enter the bloodstream, they may be carried to remote tissues, seeding new abscesses.

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