What condition is associated with a collection of pus?

An abscess is a localized collection of pus that typically forms within the tissue in response to infection. This condition arises when the body’s immune system responds to bacteria or other pathogens, leading to the accumulation of pus, which consists of dead immune cells, bacteria, and tissue debris. The formation of an abscess is usually characterized by swelling, pain, and sometimes redness in the affected area. Understanding that an abscess is fundamentally about this accumulation of pus is important for recognizing how it differs from other skin or tissue conditions.

In contrast, an ulcer is a sore that develops on the skin or mucous membrane due to the loss of surface tissue, which does not specifically involve pus accumulation. A cyst is a closed sac-like structure filled with fluid or semi-solid material, which does not necessarily relate to pus. A fistula is an abnormal connection between two hollow spaces or organs, which may or may not involve pus depending on the underlying condition but is not defined by the presence of pus itself. Thus, the association of pus with an abscess distinctly identifies it as the condition described in the question.