Suppuration

Suppuration is the process by which pus forms and is discharged as a result of inflammation, typically due to bacterial infection. Pus is a viscous mixture of dead neutrophils, bacteria, necrotic tissue, and inflammatory exudate.

Pus formation occurs when the immune system recruits neutrophils to a site of infection. These white blood cells release enzymes to combat microbes, which also causes tissue destruction and liquefactive necrosis. This can lead to the development of a localized collection of pus known as an abscess, or to diffuse purulent inflammation in surrounding tissues, sometimes termed phlegmon.

Sites and terminology: Suppurative infections can affect many tissues, including skin and soft tissue (abscesses, cellulitis with purulence), dental infections, otitis media with discharge, throat abscesses, pneumonia with purulent sputum, and intra-abdominal or pelvic abscesses. An abscess is a discrete cavity filled with pus; phlegmon refers to a more diffuse, nonlocalized purulent inflammation.

Clinical features: Local signs include redness, warmth, swelling, tenderness, and sometimes a purulent discharge. Systemic symptoms such as fever, malaise, and tachycardia may occur, especially with more extensive infections or sepsis.

Diagnosis and management: Diagnosis is clinical and supported by imaging when needed (ultrasound or CT to locate abscesses) and laboratory tests showing leukocytosis and elevated inflammatory markers. Pus cultures guide antibiotic choice. Treatment often requires drainage or incision of abscesses, plus antibiotics to cover common pathogens (such as Staphylococcus aureus and anaerobes) and supportive wound care. Severe or spreading infections may require broader antimicrobial therapy and surgical intervention.

Prognosis: With timely drainage and appropriate antibiotics, many suppurative infections resolve well; inadequate treatment can lead to chronic infection, fistula formation, or sepsis. Etymology: from Latin suppuratio, to form pus.