Definition An abscess is a collection of pus in or on the skin. An abscess usually forms in response to a bacteria infection, with Staphylococcus aureus organisms being the most common causes. However, abscesses can also be a response to a foreign body under the skin. The body responds to either the bacteria or the foreign body by sending white blood cells to the area, which forms pus.
Abscesses usually cause tender, red, swollen skin with an overlying pus head.
They can also appear as a very tender, soft lump in which the pus may not be visible. Abscesses are generally caused by an infection with Staphylococcus aureus organisms. People with AIDS, for example, have a significant risk of skin abscess. Prevention of a skin abscess starts with good hygiene. Any breaks in the skin, such as cuts, bites, or scratches, should be cleaned with soap and water before applying a bandage.