Gangrene is a serious medical condition where body tissue dies because it stops receiving enough blood. It can affect the skin, muscles, and internal organs. Without prompt treatment, gangrene can become life-threatening. Understanding the types, causes, and warning signs can help you act quickly and get the right care.
What Is Gangrene?
Gangrene occurs when blood supply to a part of the body is cut off or severely reduced. Without blood, tissue cannot survive. The affected tissue begins to die and break down.
The word “gangrene” comes from ancient Greek, where it described rotting or decaying tissue. Today, doctors use the term for any tissue death caused by poor blood supply — whether or not a bacterial infection is involved. In fact, a person can be diagnosed with gangrene without having any infection at all.
Gangrene most often affects the fingers, toes, hands, feet, and limbs. However, it can also develop in internal organs such as the appendix, colon, and lungs. Mayo Clinic provides a thorough overview of gangrene and its complications.
Types of Gangrene
There are several types of gangrene. Each type differs in how it develops, how serious it is, and how quickly it needs treatment.
Dry Gangrene
Dry gangrene happens when blood flow to an area is slowly reduced over time. The tissue dries out, shrivels, and turns dark — sometimes black or dark brown. It progresses slowly, over days or even months. Infection is usually not present with dry gangrene, which makes it somewhat less immediately dangerous than the wet type.
However, dry gangrene can still cause permanent tissue loss. Risk factors include diabetes, arteriosclerosis (hardening of the arteries), smoking, and Raynaud’s disease. If a sudden arterial blockage occurs — for example, a blood clot blocking a small artery in a finger — dry gangrene can develop within hours.
Wet Gangrene
Wet gangrene involves a bacterial infection on top of poor blood supply. It is far more dangerous than the dry type. The tissue becomes swollen, blistered, and may ooze a foul-smelling discharge. Without urgent treatment, wet gangrene can lead to sepsis (a life-threatening blood infection) within hours or days.
Common causes include severe burns, knife wounds, or other injuries that damage blood vessels and allow bacteria to enter. Wet gangrene can develop quickly, so immediate medical attention is critical.
Gas Gangrene
Gas gangrene is rare but extremely severe. It occurs when deep tissue or muscle is injured — often during trauma or surgery. A type of bacteria called Clostridium infects the wound and produces toxins and gas beneath the skin.
The skin may appear pale at first, then turn a greyish colour. When you press the skin, you may hear or feel a crackling sound from the gas trapped underneath. Gas gangrene can be fatal within 48 hours if not treated as a medical emergency.
Internal Gangrene
Internal gangrene affects organs inside the body, most commonly the appendix or colon. It can also involve the gallbladder. When blood flow to these organs is blocked, the tissue begins to die. This type of gangrene causes fever, severe abdominal pain, and a general feeling of being very unwell.
Fournier’s Gangrene
Fournier’s gangrene is a rare but serious infection that affects the genital area. It is more common in men. The infection spreads rapidly and destroys tissue. Left untreated, it can lead to sepsis and death. It requires emergency surgery and is considered a medical crisis.
Meleney’s Gangrene
Meleney’s gangrene is another rare type. It causes painful skin lesions that appear one to two weeks after surgery or a minor injury. It progresses slowly but causes significant tissue damage and requires specialist care.
Causes and Risk Factors of Gangrene
Gangrene develops when blood supply to tissue is interrupted. This can happen due to injury, infection, or underlying health conditions. Several factors increase your risk.
Common causes and risk factors include:
Diabetes: High blood sugar damages blood vessels and nerves, especially in the feet. This is often called diabetic foot.
Peripheral artery disease (arteriosclerosis): The arteries harden and narrow, reducing blood flow to the limbs.
Atherosclerosis: Fatty deposits (cholesterol) build up inside artery walls and block blood flow.
Smoking: Nicotine narrows blood vessels and reduces circulation.
Raynaud’s disease: A condition where blood vessels in the fingers and toes spasm in response to cold or stress.
Serious open wounds: Deep cuts, burns, or traumatic injuries can disrupt blood supply and allow bacteria to enter.
Weakened immune system: Conditions such as HIV infection or treatments like chemotherapy reduce the body’s ability to fight infection.
Healthline explains how underlying conditions like diabetes significantly raise gangrene risk.
Symptoms of Gangrene to Watch For
Symptoms of gangrene depend on the type and location. Catching them early can make a major difference in your outcome.
Skin and External Symptoms
When gangrene affects the skin or areas just beneath it, you may notice:
Colour changes in the skin — blue or black if the skin itself is affected; red or yellowish if the tissue beneath the skin is involved
A foul-smelling discharge from the affected area
Loss of feeling (numbness) in the area
Severe pain in or around the affected tissue
Skin that looks dry, shrunken, or shrivelled (in dry gangrene)
Swelling and blistering (in wet gangrene)
Internal Symptoms
When gangrene develops inside the body — for example, in an organ — the symptoms are different. You may experience:
Persistent or severe pain in the affected area
Fever and chills
A general feeling of being very unwell
Confusion or disorientation
Low blood pressure
Gas trapped under the skin (a crackling feeling when the skin is pressed)
Signs of Septic Shock — Call 911 Immediately
Wet gangrene can spread infection throughout the body, leading to a dangerous condition called septic shock. This is a life-threatening emergency. Call 911 or go to your nearest emergency department right away if you notice:
A rapid, weak pulse
Dizziness or lightheadedness when standing up
Sudden confusion or loss of awareness
Difficulty breathing, vomiting, or diarrhoea
Cold, pale, or clammy skin
How Is Gangrene Diagnosed?
Doctors usually diagnose gangrene based on a physical examination and your symptoms. However, additional tests are often needed to confirm the diagnosis and find out how far it has spread.
Common diagnostic tools include:
Blood tests: To check for signs of infection or inflammation.
Imaging tests: X-rays, CT scans, or MRI scans help doctors see how much tissue is affected and detect gas in the tissue.
Arteriography: A contrast dye is injected into an artery, and X-ray images are taken to assess blood flow. This helps identify blockages.
Tissue or fluid cultures: Samples are taken from the wound to identify which bacteria are causing the infection. This guides antibiotic treatment.
Surgery exploration: In some cases, surgeons need to look directly at the tissue to understand how serious the gangrene is.
In Canada, your family doctor or emergency physician will coordinate these tests. Many of these are covered under your provincial health plan. Health Canada outlines coverage and access to medically necessary services across provinces.
Treatment Options for Gangrene
Treatment depends on the type of gangrene, its location, and how advanced it is. The main goals are to remove dead tissue, restore blood flow, and treat any underlying infection.
Common treatments include:
Surgery (debridement): Doctors remove dead or infected tissue to prevent the gangrene from spreading. In severe cases, amputation of a limb or digit may be necessary.
Antibiotics: Used to treat or prevent bacterial infection, especially in wet gangrene. They are given intravenously (through an IV) in a hospital setting.
Vascular surgery: To restore blood flow to the affected area. This may involve bypassing a blocked artery or removing a clot.
Hyperbaric oxygen therapy: The patient breathes pure oxygen in a pressurised chamber. This helps increase oxygen in the blood and can support healing in certain types of gangrene, including gas gangrene.
Skin grafting: Once the infection is controlled, surgeons may use healthy skin to cover areas where tissue was removed.
Recovery from gangrene can be long and complex. Many patients require rehabilitation and follow-up care through their provincial health system. Always follow your care team’s instructions closely.
When to See a Doctor
Do not wait if you suspect gangrene. This condition can worsen very quickly. If you notice unusual colour changes, unexplained pain, numbness, or a foul smell from any area of your body, contact your family doctor right away.
If you cannot reach your family doctor, visit a walk-in clinic as soon as possible. Many provinces have nurse practitioner-led clinics that can assess urgent concerns quickly. However, if you have signs of septic shock — rapid pulse, confusion, difficulty breathing, or cold, pale skin — call 911 or go to your nearest emergency department immediately. Do not drive yourself.
Canadians with diabetes or circulation problems should have their feet checked regularly by a healthcare provider. Catching problems early is the best way to prevent gangrene from developing in the first place. As always, speak with your family doctor or a qualified healthcare professional before making any decisions about your health.
Frequently Asked Questions About Gangrene
What does gangrene look like in its early stages?
In its early stages, gangrene may cause the skin to look red, pale, or slightly discoloured. The affected area might feel numb or unusually painful. As gangrene progresses, the skin can turn blue, grey, or black, and a foul smell may develop.
Can gangrene be cured without amputation?
In some cases, yes — especially if gangrene is caught early. Doctors may use antibiotics, surgery to remove dead tissue, and procedures to restore blood flow. However, in severe cases, amputation may be the only way to stop gangrene from spreading and save a person’s life.
Is gangrene contagious?
Gangrene itself is not contagious — you cannot catch it from another person. However, the bacteria that cause wet gangrene or gas gangrene can spread within the same person’s body if the infection is not treated promptly. Always seek medical care quickly if you suspect gangrene.
What is the connection between diabetes and gangrene?
People with diabetes are at higher risk of developing gangrene, particularly in the feet. High blood sugar damages both blood vessels and nerves, reducing circulation and sensation. This means injuries may go unnoticed and heal poorly, creating conditions where gangrene can develop.
How quickly does gangrene spread?
The speed depends on the type of gangrene. Dry gangrene progresses slowly — over days or months. Wet gangrene and gas gangrene, however, can spread within hours and become life-threatening very quickly. This is why gangrene always requires urgent medical assessment.
What are the early warning signs of gangrene in the foot?
Early signs of gangrene in the foot include persistent pain, numbness, or a cold feeling in the toes or foot. Skin colour changes — such as redness, paleness, or darkening — are also warning signs. Anyone with diabetes or poor circulation should check their feet daily and report any changes to their family doctor right away.
Key Takeaways
Gangrene is the death of body tissue caused by a loss of blood supply, with or without infection. The main types are dry gangrene, wet gangrene, gas gangrene, internal gangrene, Fournier’s gangrene, and Meleney’s gangrene. Wet gangrene and gas gangrene are the most dangerous types and can become fatal within hours without treatment. Major risk factors include diabetes, poor circulation, smoking, and a weakened immune system. Early symptoms include skin colour changes, numbness, severe pain, and foul-smelling discharge. Signs of septic shock — confusion, rapid pulse, difficulty breathing, cold skin — require an immediate call to 911.
