Abscess

An abscess is a localized collection of pus within tissue, organ, or a potential space, resulting from infection and inflammation. The pus consists of neutrophils, dead cells, and bacteria. Over time, the body may form a fibrous capsule around the collection, separating it from surrounding tissue.

Most abscesses are bacterial. Skin abscesses are common and often caused by Staphylococcus aureus; dental abscesses arise from infected teeth; abscesses can occur in the liver, lung, brain, abdomen, or pelvis. Risk factors include diabetes, immune suppression, poor hygiene, and penetrating injuries. Noninfectious abscess-like collections can occur with foreign material or inflammatory disease.

Clinically, an abscess presents with localized pain, swelling, redness, warmth, and tenderness. Fluctuance—a soft, compressible area—may be felt. Fever and malaise can accompany the infection. Diagnosis is usually clinical; imaging such as ultrasound or CT helps identify deep or inaccessible abscesses and guides drainage. Blood tests may show leukocytosis or elevated inflammatory markers.

The primary treatment for most superficial abscesses is incision and drainage. Antibiotics are used when there is surrounding cellulitis, systemic signs, immunosuppression, extensive disease, or involvement of critical spaces; they are not always needed after drainage of a simple cutaneous abscess. Wound care, analgesia, and monitoring for recurrence are important. Dental abscesses require source control (drainage) and dental treatment such as root canal therapy or extraction, with antibiotics as an adjunct.

Prognosis is generally favorable after adequate drainage. Complications can include spread to adjacent spaces, sepsis, osteomyelitis, or septic arthritis, though these are uncommon with prompt treatment. Prevention focuses on good hygiene, prompt treatment of infections, and routine dental care.