Necrosis is the general term for tissue dying, anywhere in the body and from any cause. Gangrene is a specific kind of necrosis: a substantial mass of tissue dying, usually from lost blood supply, and typically in a limb or extremity. All gangrene is necrosis; most necrosis is not gangrene.
The core difference
- necrosis — the death of cells or tissue from injury, infection, toxin or loss of blood supply. A general pathological term.
- gangrene — necrosis of a sizeable volume of tissue, most often caused by interrupted blood supply, commonly affecting toes, feet, fingers or bowel.
Scale and setting
Necrosis describes what is happening at tissue level and can be microscopic — a small patch inside an organ found only under a microscope. Gangrene is a clinical picture: enough tissue has died to be visible and to require treatment.
The types of gangrene
- Dry gangrene — from gradual loss of arterial supply. The tissue dries, darkens and shrinks, with a clear line between living and dead. Slow, and associated with diabetes and peripheral arterial disease.
- Wet gangrene — bacterial infection is present. Swelling, blistering and rapid spread. A medical emergency.
- Gas gangrene — caused by Clostridium bacteria producing gas within the tissue. Rapid and life-threatening.
Apoptosis, the orderly opposite
Worth knowing because it is often contrasted: apoptosis is programmed cell death, a controlled process the body uses deliberately during development and maintenance. Necrosis is uncontrolled and triggers inflammation; apoptosis is tidy and does not. Cells dying is not always pathological.
Where the words come from
Necrosis is Greek nekros, a corpse — the same root as necropolis, a city of the dead. Gangrene comes through Latin from Greek gangraina, meaning a spreading sore. Despite the spelling it has nothing to do with green; the resemblance is coincidence.
This page explains the words, not your symptoms. Anything of concern is a matter for a doctor.
Frequently asked questions
Is gangrene the same as necrosis?
No. Necrosis is the general term for tissue dying. Gangrene is a specific kind — a large mass of tissue dying, usually from lost blood supply.
What is the difference between dry and wet gangrene?
Dry gangrene follows gradual loss of blood supply and progresses slowly. Wet gangrene involves bacterial infection, spreads rapidly and is a medical emergency.
Is gangrene named after the colour green?
No. It comes from Greek gangraina, a spreading sore. The similarity to green is coincidental.