Abscess
Abscess, collection of pus , a thick, yellowish fluid caused by bacterial, protozoan, or fungal invasion of body tissues. Abscesses can occur in the skin, in the gums, in bone, and in body organs, such as the liver , the lungs , and even the brain. The area of the abscess becomes red and swollen; sensations of pain and localized heat are common. If the inflamed tissue encompassing the infected cavity thins out sufficiently, the abscess may rupture. Treatment may involve surgical incision or use of antibiotics or both.