What Is Gangrene?

Gangrene is a serious condition in which a part of the body begins to decay. This process is often described as tissue death or necrosis. Gangrene can occur when an extremity of the body—hands, feet, nose, ears—becomes severely deprived of blood flow or develops an overwhelming infection.

Gangrene can result in sepsis (blood infection) or complete loss of the affected extremity. It can worsen rapidly and is life-threatening if left untreated. Learn more about the symptoms, causes, diagnosis, and treatment of this serious condition.

Causes

Several situations cause gangrene to develop, including a lack of blood flow to the extremities or a severe infection of an extremity. There are a number of risk factors that increase the chances of developing this condition.

A severely infected wound of a susceptible region of the body can cause gangrene as well, particularly when a lack of blood flow interferes with the immune system’s ability to reach the infection.

There are several conditions that increase the risk of developing gangrene:

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Diabetes: Type 1 and type 2 diabetes mellitus can cause or accelerate atherosclerosis, which is a disease of the blood vessels that reduces blood flow in the small blood vessels of the body. Diabetes can also cause impaired wound healing and a weakened ability to fight off infections.

Neuropathy: A condition characterized by decreased sensation of the hands and feet, neuropathy does not directly cause gangrene. However, it substantially increases the chances of developing gangrene because it reduces your ability to adequately feel pain—a sensation that normally protects you from injuries and infections.

Vascular disease: Disease of blood vessels can result in obstruction of blood flow. In addition to diabetes, smoking, hypertension (high blood pressure), high cholesterol, obesity, and genetics can all promote the development of vascular disease.

Pressure sore: A wound can develop on the surface of the skin due to long-term pressure. You may be at risk of developing a pressure sore if you have a condition that prevents you from moving and turning in bed, such as a stroke, spine disease, or obesity.

Sometimes, a person who is debilitated due to dementia, a stroke, or cancer may not be able to communicate the pain of a pressure sore. If you have a loved one who is too ill to move, it is important to try to keep an eye on areas of the skin that are pressed against a hard surface for too long, such as the hips, buttocks, elbows, heels, and shoulders.

Traumatic injury: If you experience a major traumatic injury, it can make you susceptible to an aggressive infection. Severe trauma can also cause compression of injured regions of the body, preventing adequate blood flow. 

Weak immune system: A weak immune system makes it difficult for you to fight infections. 

Constriction: Tight constrictive pressure wrapped around an arm, leg, finger, or toe can suddenly diminish blood supply. 

Frostbite; Exposure to extreme cold can reduce blood flow to your digits (fingers and toes), as well as your ears and nose. These areas, described as the periphery of your body, can lose adequate blood supply in extremely cold temperatures, and may completely lose function due to frostbite. 

Drug use; Intravenous (IV) drug use increases exposure to certain infectious bacteria, which can cause gangrene.

Types

If you have gangrene, you may be diagnosed with a specific type of gangrene, and there are some overlapping characteristics among these different types.

• Dry gangrene. This is one of the most common types of gangrene, and it occurs when there is a lack of blood flow to an extremity due to vascular disease (including vascular disease, diabetes, or frostbite). This type of gangrene is not typically associated with an infection. If left untreated, tissues necrosis can occur.
• Wet gangrene. Wet gangrene is tissue death associated with an infection. This is a more serious condition than dry gangrene and is more likely to cause dangerous complications. The bacterium that most commonly causes wet gangrene is called Staphylococcus aureus.

In addition, there are specific types of wet gangrene which include the following:

• Gas gangrene. An infection of a gangrenous limb can involve bacteria that produce gas bubbles. This is a type of infected wet gangrene, and it is particularly harmful. The bacterium that most commonly causes gas gangrene is called Clostridium perfringens.
• Fournier’s gangrene. This is a rare type of aggressive, infectious wet gangrene characterized by the presence of more than one infectious microbe.

Symptoms

The visible signs of gangrene are usually more noticeable than symptoms of pain or discomfort. While it is not an absolute rule, gangrene is often characterized by a lack of early symptoms. This is because gangrene can cause decreased sensation in the affected extremity and it often occurs in an area of the body that already has impaired sensory function.

In fact, if someone you live with develops gangrene, you may notice visible signs before your loved one even feels any symptoms. Subtle signs or symptoms can last for days, but sometimes, gangrene can progress rapidly—as quickly as within a few hours.

While it often starts in the periphery, gangrene may work its way closer to your core. For example, it can begin at the tip of the toe, spread throughout the whole toe, and then into the foot.

The most common symptoms of gangrene include:

• exceptionally dry skin (possibly peeling skin)
• skin color may change to blue, deep red, or greenish-black
• areas of bleeding underneath the skin
• numbness or tingling in and around the affected area
• swelling or puffiness of the affected area
• pain or throbbing in or near the affected area
• warmth of the affected area
• an open, non-healing wound
• a pus-filled lesion
• a wound that smells bad
• a fever can develop
• the affected area may be cool to the touch
• the affected area may feel cold as if it is "bare," even when covered

While it is far less common, gangrene can affect internal organs as well. The intestines and gallbladder are the organs that are most prone to gangrene.

The symptoms of internal gangrene may be difficult to recognize because they are similar to symptoms of other digestive problems including nausea, vomiting, loss of appetite, severe stomach pain, and fevers.

Complications 

Gangrene typically begins in one or a few areas of the body. It may result in complete necrosis of the affected region, or a severe infection can spread throughout the body. Complications of gangrene may include a variety of conditions.

Tissue Necrosis

Gangrene is often described as dying tissue or dead tissue. A gangrenous area of the body can become completely necrotic, which means that there is no chance of survival. When this occurs, the area must be amputated (surgically removed).

Necrotizing Fasciitis

Necrotic tissue can become severely infected, usually due to bacteria from the skin’s surface. This condition is often associated with warmth, pain, and swelling of the affected region. 

Sepsis and Shock

A gangrenous infection can spread throughout the body, resulting in sepsis. Early symptoms of sepsis include a general feeling of fatigue, fever, headache, loss of appetite, nausea, or vomiting. Sepsis can rapidly worsen, resulting in septic shock—this is the inability of the body to cope with the infection.

Symptoms of shock include low blood pressure, a fast heart rate, rapid, shallow breathing, and fainting or loss of consciousness. 

Diagnosis

Gangrene is typically a clinical diagnosis, which usually relies only on the appearance of the affected area. Your healthcare provider may also send a few tests to help identify whether you have an infectious organism and determine the best way to treat it.

Wound Culture

This is a quick and painless procedure in which your healthcare provider may swab an open lesion on the affected area to send a sample to a lab for a culture. With a culture, the sample is placed in a substance that allows the bacteria to grow so that it can be identified.

Growth and identification can take a few days, but it helps your practitioners select the most targeted and powerful treatment if you have a gangrenous infection.

Internal gangrene is usually diagnosed using imaging tests, such as an X-ray, a computerized topography (CT) scan, an ultrasound, or a magnetic resonance imaging (MRI) test.

Treatment

If you develop signs of gangrene, you need to seek urgent medical attention to minimize the effects. There are several medical and surgical treatment strategies for gangrene. 

A primary goal of treating wet gangrene (caused by infection) is to attempt to cure the infection with antibiotics. A main goal in treating dry gangrene (where blood flow is the main problem) is to attempt to improve blood flow.

Furthermore, with either type of gangrene, removing dead tissue is important—debridement or amputation is often necessary.

Antibiotics

You may need treatment with oral (by mouth) antibiotics or with IV antibiotics to control your infection if you have wet gangrene. Your healthcare providers may begin antibiotics immediately with a broad-spectrum antibiotic that kills most bacterial infections.

If your cultures come back showing that you are infected by a type of bacteria that does not respond to the antibiotic you are taking, then your practitioners may switch to another antibiotic. 

Other Treatment Types

Sometimes, small areas of tissue can be removed from the gangrenous area, saving as much healthy tissue as possible. The process of removing this tissue is called debridement.

Hyperbaric oxygen is also a potential treatment. This involves sitting in a chamber to breathe air that contains more concentrated oxygen than the air around us. The purpose of this therapy is to optimize healing.

In addition, if you have gangrene, a blood vessel bypass may prevent additional gangrene from developing in susceptible nearby tissue—though it cannot revive tissue that is already dead.

Interestingly, the use of sterile maggots is making a comeback in treating gangrene. Maggots are excellent at eating away dead tissue while leaving viable tissue alone. Of course, this treatment type would also be under the close monitoring of a person's healthcare provider or healthcare professional.

Amputation

In some situations, a digit, or even a hand or a foot, cannot be saved. In these situations, amputation is necessary to prevent a life-threatening infection from spreading throughout the whole body.

If you develop systemic effects of gangrene, such as sepsis or shock, you will need more extensive treatment, including IV antibiotics and fluids and support for your heart, kidney, and lung function as you recover.

Prevention

If you have risk factors for developing gangrene, there are steps you can take to prevent it. Being aware of the possibility of gangrene is an important aspect of prevention, particularly because gangrene doesn’t always cause pain.

Taking Care of Skin

Strategies for preventing gangrene include inspecting your skin. If you have diabetes, be sure to carefully look at your fingers, elbows, heels, and toes on a daily basis so that you can detect small wounds or mild skin discoloration before gangrene develops.

If you have a wound, be sure to cover it with a bandage so that it won’t become infected. Change your bandage regularly. Clean wounds with warm water or a gentle antiseptic before covering with a bandage to prevent infections.

Take care of your skin, especially if you have neuropathy. Be mindful that you might not feel pain from stubbing your toe, wearing tight shoes, or a hangnail. Make sure you prevent these events by wearing shoes that are not too tight and by keeping your fingernails and toenails clean and trimmed.

If you or a loved one is immobilized, be sure to schedule consistent turning in bed (or in a chair) so that pressure sores won’t develop.

Tips for Cold Weather

Wear gloves and warm socks when you are out in the cold so you won’t get frostbite. If you feel your fingers, toes, ears or nose becoming numb or losing sensation, get indoors and warm these extremities gradually with fabric or warm water, not with hot water. Seek urgent medical attention if you don’t feel better within a few minutes.

Overall Health

If you smoke, it is best to stop. Smoking contributes to vascular disease which can, in some cases, contribute to gangrene.

In addition, poorly controlled blood sugar leads to vascular disease, increasing your chances of developing gangrene. You can manage your blood sugar with diet and medication if you have diabetes or pre-diabetes.

Hypertension is one of the causes of vascular disease, and the prevention of vascular disease reduces your risk of gangrene. Anti-hypertensive meditation, exercise, and diet are all ways of controlling hypertension.

In some instances, an extremity is in danger of developing gangrene due to severe vascular disease. If this is your situation, you may need to have a surgical vascular bypass, which is repair of a diseased blood vessel to allow better blood flow to a region of the body that is at risk of gangrene.

A Word From Verywell

If you or a loved one is at risk of developing gangrene, it is important to focus on prevention. If you have already experienced complications of gangrene, particularly an amputation, you will have to adjust to your new limitation. The loss of a finger, toe, or a whole limb requires substantial physical therapy so that you can function as well as possible. Be persistent with checking your skin for signs of infection, especially if you don't have sensation in certain areas. Discuss your options with your healthcare provider. Though you can't revive dead tissue, you can often prevent gangrene from spreading.