abscess
Meaning of abscess: The wall that keeps the infection contained also keeps antibiotics out, which is why most abscesses are settled by drainage rather than by medication alone.
Definition of abscess
An abscess is a pocket of pus walled off within tissue, formed when the body contains an infection it cannot clear. Pus is a mixture of dead white blood cells, bacteria, broken tissue and fluid. The surrounding tissue inflames and builds a fibrous wall around the collection, which stops the infection spreading but also seals it away from the bloodstream.
How does one form?
Organisms reach the tissue through a break in the skin, a blocked gland or hair follicle, a tooth eroded by decay, or from a leak inside the body. The immune system sends neutrophils in numbers, and the enzymes they release to kill bacteria also digest the tissue around them into liquid. That liquid, with dead cells and organisms in it, accumulates under pressure. The body then lays down a barrier of inflamed and later fibrous tissue around it. The result is the familiar picture: a swollen, red, warm and tender area that feels soft or springy in the middle where fluid moves under the finger, painful because the collection presses outward with nowhere to go.
Where do abscesses form?
| Site | What it usually follows |
|---|---|
| Skin and soft tissue | A blocked hair follicle or a break in the skin; a boil is the small version |
| Tooth and jaw | Decay or a crack reaching the pulp at the center of the tooth |
| Abdomen | A perforated bowel, appendicitis, or a leak after surgery |
| Liver and lung | Spread through the bloodstream, or material inhaled into the lung |
| Brain | Spread from the ear, sinuses or bloodstream, uncommon but serious |
How is it different from cellulitis?
Cellulitis is a spreading infection of the skin and the tissue beneath it, with no defined collection of fluid: the area is red, warm and tender, but there is nothing to drain. An abscess is a discrete pocket. The distinction determines what happens next, and the two frequently occur together, with cellulitis surrounding an abscess within it. Ultrasound or a scan settles the question when examination cannot, by showing whether a fluid collection is present. Fever, a rising white cell count and feeling generally unwell suggest that the response has extended beyond the local site.
Also known as
Used in a sentence
Imaging identified a fluid collection consistent with an abdominal abscess.
Good to know
An abscess is a contained collection of pus and is distinct from cellulitis, a spreading infection of the skin and underlying tissue with no defined pocket of fluid.
Word origin
Where “abscess” comes from
From Latin abscessus, meaning a going away, from abscedere, formed from ab-, meaning away, and cedere, meaning to go, reflecting an old belief that diseased matter withdrew from healthy tissue.