Gangrene

About gangrene

Gangrene can occur as a result of an injury, infection or a long-term condition that affects blood circulation.

Symptoms of gangrene

The symptoms of gangrene vary depending on the cause. It can affect any part of the body. But it typically starts in the toes, feet, fingers or hands.

General symptoms of gangrene include:

• initial redness and swelling 
• either a loss of sensation or severe pain in the affected area
• sores or blisters that bleed or release a dirty-looking or foul-smelling discharge (if the gangrene is caused by an infection)
• the skin becoming cold and pale

In some cases, the affected limb may feel heavy and pressing the skin may produce a crackling sound. These symptoms are caused by a build-up of gas under the skin.

If the area is infected, you may also have other signs related to the underlying infection, such as:

• a high temperature (fever)
• loss of appetite
• rapid heartbeat and breathing
• dizziness
• shivering

Without treatment the affected tissue will start to die. When this happens, the area changes colour from red to brown to purple or black, before shrivelling up and falling away from the surrounding healthy tissue.

When to get medical advice

The earlier treatment for gangrene begins, the more effective it's likely to be. Contact your GP immediately if you have:

• any of the symptoms of gangrene mentioned above
• a persistent fever
• a wound that's unusually slow to heal

If your GP isn't available, call GP out of hours service for advice.  

When to get emergency help

If bacteria from gangrene pass into your bloodstream, you could go into septic shock. This is a life-threatening condition that occurs when an infection causes your blood pressure to drop to a dangerously low level.

Signs of septic shock include:

• a rapid but weak pulse
• dizziness when you stand up
• a change in your mental state, such as confusion or disorientation
• difficulty breathing
• vomiting
• diarrhoea
• cold, clammy and pale skin

Dial 999 immediately for an ambulance if you think that you or someone you know is in septic shock.

Who's affected

Anyone can develop gangrene, particularly after a serious injury. But there are certain groups of people who are more at risk of developing gangrene.

These include people with long-term conditions that can affect the blood vessels, such as:

• diabetes – a lifelong condition that causes a person's blood sugar level to become too high
• atherosclerosis (arteriosclerosis) – where the arteries become clogged up with a fatty substance called plaque, narrowing them and restricting blood flow 
• peripheral arterial disease – where a build-up of fatty deposits in the arteries restricts blood supply to leg muscles
• Raynaud's phenomenon – where blood vessels in certain parts of the body, usually the fingers or toes, react abnormally to cold temperatures

How gangrene is treated

The earlier treatment for gangrene begins, the more successful it's likely to be. The main treatments include surgery to remove damaged tissue and antibiotics to treat any underlying infection.

In some cases, surgery may be needed to restore blood flow to the affected area.

In more severe cases, it may be necessary to remove an entire body part such as a toe, foot, or lower leg. This is known as amputation.

Preventing gangrene

Many cases of gangrene can be prevented.

If you have a condition that increases your risk of getting gangrene, such as diabetes, it's important you have regular check-ups to assess the state of your feet.

Report any problems to your GP as soon as possible.

Stopping smoking if you smoke and adopting a healthy lifestyle, with a low-fat diet and regular exercise, can also improve your circulation and reduce your risk of developing gangrene.

• Find out more about gangrene on the NHS website

More useful links

• How to use your health services