An abscess is a localized collection of pus that builds up within the tissues of the body. It is essentially your immune system’s way of “walling off” an infection to prevent it from spreading to the rest of your body.

While most people encounter skin abscesses (often called boils), they can actually form anywhere—including on your teeth, inside your organs, or even in your brain.

Types:-

• Pyogenic abscess.
• Pyaemic abscess.
• Metastatic abscess.
• Cold abscess due to chronic infection like tuber­ culosis.

• Pyogenic Abscess :-

• It is a localised collection of pus in a cavity lined by granula-tion tissue, covered by pyogenic membrane. It contains pus in loculi. Pus contains dead WBC’s, multiplying bacteria, toxins and necrotic material.
  Protein exudation causes fibrin deposition and formation of pyogenic membrane.
  Macrophages and polymorphs release lysosomal enzymes which cause liquefaction of tissues leading into pus formation.
  Toxins and enzymes released causes tissue destruction and pus formation.

Mode of infection:-