The symptoms of gangrene can vary depending on the underlying cause.
Gangrene caused by a health condition
If the gangrene is caused by an underlying condition such as diabetes disrupting the blood supply to certain parts of the body (dry gangrene – which is the most common type of gangrene), then you will experience the following symptoms:
- the affected body part often first turns red
- it then becomes cold, pale and numb (though some people will experience pain)
- without treatment the body part will begin to die – it changes colour from red to brown to black before the dead tissue then shrivels up and falls away from the surrounding healthy tissue
Gangrene caused by injury
If the gangrene is caused by a wound, burn or area of frostbite becoming infected by bacteria (wet gangrene – which progresses much faster than dry gangrene), symptoms can include:
- swelling and redness of the affected body part
- pain which can often be severe
- foul-smelling discharge of pus from a sore in your skin
- affected area will change colour – from red to brown to black
You may also experience more general symptoms related to the underlying infection, such as:
- a high temperature (fever) of, or above, 38C (100.4F)
- loss of appetite
- rapid heartbeat and breathing
- a drop in blood pressure, which can make you feel dizzy
- shivering
If the gangrene is due to a serious skin infection (necrotising fasciitis) symptoms include:
- redness, swelling and pain; the pain much more severe than usual in a typical skin infection
- the affected skin becomes tense and reddened
- the skin can change colour to purple or black
- extensive blistering can occur and the blisters can bleed or release a dirty-looking fluid (some people have described the fluid as looking like dishwater)
- other symptoms of sepsis such as vomiting and diarrhoea can occur due to production of toxins (poisons) from bacteria inside the body
If the gangrene is due to an infection developing inside your body (gas gangrene or internal gangrene) symptoms include:
- a feeling of heaviness followed by severe pain
- in most cases of gas gangrene, pressing skin near the affected area will produce a crackling sound caused by a build-up of gas; it feels like crushing fine tinfoil
When to seek help
The earlier treatment begins, the more successful it is likely to be. Contact your GP immediately if you notice any of these symptoms:
- skin that is cold, hard, numb and pale
- a persistent, unexplained, severe pain
- a persistent, unexplained fever
- a wound that is unusually slow to heal
- a wound that produces pus or discharge
- a wound that produces a strong, bad smell
If your GP is not available, call NHS Direct on 0845 46 47 or your local out-of-hours service.
When to seek emergency medical advice
If bacteria from gangrene pass into your bloodstream, you could go into septic shock. This is a condition where bacteria multiply in the blood, releasing toxins that damage cells and organs, dramatically lowering your blood pressure.
Signs of septic shock include:
- a rapid but weak pulse
- reduced urine flow
- mental confusion
- pale-looking skin
- breathing difficulties
- cold, clammy skin (in the later stages)
If you suspect that you, or someone you know, has septic shock, dial 999 to request an ambulance immediately.
