What are the warning signs of gangrene?

Gangrene is a serious condition that occurs when body tissue dies due to a lack of blood supply or a serious bacterial infection. It usually affects the extremities, such as the toes, fingers, hands and feet. However, it can also occur in internal organs. Gangrene requires prompt medical attention to stop its spread and prevent serious complications, including amputation of the affected area. Knowing the early signs and symptoms of gangrene allows for quick diagnosis and treatment. This article will cover the common warning signs and symptoms that signal gangrene may be developing.

What is Gangrene?

Gangrene refers to the death of body tissue due to either a lack of blood flow or a bacterial infection. When blood flow is restricted or blocked, the deprived tissue begins to die. This is known as ischemic gangrene. An infection can also directly destroy tissue and cause gangrene, known as infectious gangrene.

Certain health conditions increase the risk of developing gangrene. These include:

– Diabetes – poor circulation and nerve damage make diabetics susceptible
– Atherosclerosis – hardening and narrowing of arteries restricts blood flow
– Injuries – trauma can damage blood vessels and introduce bacteria
– Frostbite – icy temperatures constrict vessels
– Burns – damaged skin is prone to infections

Gangrene often starts in the extremities, such as the fingers, hands, toes and feet as these areas are farthest from the heart. However, it can occur in any part of the body with compromised circulation or infection. Internal organs like the gallbladder, intestines, and appendix may also become gangrenous.

Prompt treatment is vital to stop the spread of gangrene. Without treatment, it spreads quickly and can be fatal.

Warning Signs and Symptoms

Recognizing the early signs and symptoms of gangrene allows for prompt treatment. The following are warning signs to watch out for:

Changes in Skin Color

One of the earliest signs of gangrene is changes to the color of the skin in the affected area. This occurs as the tissue begins to die due to lack of blood flow. The skin may first become reddened before turning purplish-black as the tissue dies. The discoloration may appear in patches or cover a whole extremity.


Numbness and tingling of the skin often accompanies the changes in skin color. This is due to the nerve damage caused by the lack of circulation to the tissues. The area loses sensation as the nerve cells begin to die off.

Blisters or Ulcers

As the skin and soft tissue dies, blisters or open sores may begin to develop. These blisters contain serous fluid and can rupture to form ulcers or open wounds on the skin’s surface.

Pain and Tenderness

Moderate to severe pain and tenderness is common as gangrene sets in. This occurs even with light touch due to the nerve damage. The pain often precedes the changes in skin color and sensation.


The affected extremity or area may become swollen as inflammation and edema sets in. The swelling can range from mild to severe.


A fever often accompanies infectious gangrene as the body attempts to fight the tissue infection. A high fever indicates a fast progression of the gangrene.

Weak Pulse

The dying tissue lacks adequate blood flow and nutrients. This may cause the pulse in the affected limb or area to weaken.

Foul Odor

As the gangrenous tissue decays, it emits a foul odor. This is due to the rotting tissue and presence of anaerobic bacteria.

Peeling or Shedding Skin

In late stages, the dead skin begins to peel away and shed off the area in sheets. The underlying tissue appears blackened.


An infected gangrenous wound produces a discharge, which may be thin and watery, bloody or purulent. Bacterial infection causes pus formation.

Locations Where Gangrene Occurs

While gangrene can occur anywhere in the body, certain locations are more commonly affected. These include:

Toes and Feet

The toes and feet are frequent sites as they are farthest from the heart. In diabetics, gangrene of the feet is known as diabetic foot and often leads to amputation. The heels and soles are often first affected.

Fingers and Hands

The fingers and hands also regularly develop gangrene due to their distance from the heart and frequent injuries. Raynaud’s disease is a circulatory disorder that can cause finger gangrene.


Lower limbs like the legs are more prone than upper limbs. Gangrene may start in the feet and spread upwards in the leg. Arm gangrene is less common but can occur from injury.

Organs and Tissue

Internal organs can also develop gangrene, often due to infections spreading from elsewhere in the body. Bowel, intestinal and gallbladder gangrene may result from abdominal infections. Gangrene can also affect body tissue like fat and muscle.

Patches on Skin

Small, patchy areas of gangrene may occur on the skin surface due to minor infections or blood vessel damage from injury.

Causes and Risk Factors

Gangrene results from either impaired blood circulation or serious bacterial infections. Understanding the causes and risk factors helps identify those most vulnerable.


Diabetes is a major risk factor. High blood sugar damages nerves and blood vessels, impairing circulation, particularly in the extremities. Diabetic foot gangrene is a severe complication.


Hardening and narrowing of the arteries restricts blood flow and can lead to tissue death. Peripheral arterial disease increases gangrene risk.


Trauma can damage blood vessels or introduce bacteria resulting in gangrene. Crush injuries, fractures, burns and wounds can directly cause gangrene.


Exposure to freezing temperatures constricts blood flow. Frostbitten areas like the fingers, ears, cheeks and toes are at risk of gangrene.

Immune Impairment

Individuals with weakened immune systems due to medications, HIV/AIDS or cancer are vulnerable to infections causing gangrene.

Blood Disorders

Blood diseases like leukemia and sickle cell anemia impair circulation increasing gangrene risk. Clots can also cut off blood supply.


Smoking causes arterial damage leading to poor circulation and higher gangrene risk, especially in diabetics.

Alcohol Abuse

Excess alcohol weakens immunity, damages nerves and constricts blood vessels. All increase susceptibility to gangrene.

Bowel Diseases

Chronic bowel diseases like Crohn’s or diverticulitis can infect the intestinal wall and surrounding tissue leading to gangrene.


Certain medications like chemotherapy drugs and anti-rejection drugs for transplants can increase the risk by damaging nerves or blood vessels.

When to See a Doctor

It is important to seek prompt medical attention if gangrene is suspected. Waiting allows it to quickly progress and worsen outcome. Seek emergency care for:

– Severe or worsening pain
– Changes in skin color or temperature
– Numerous blisters or sores
– Signs of infection like fever or pus
– Blue or black skin discoloration
– Loss of sensation
– Skin peeling off in sheets
– Foul odor from wound

Call a doctor for milder symptoms like:

– Moderate pain or tenderness
– Skin redness or purplish color
– Mild fever
– Swelling or inflammation
– Small skin blisters or ulcers

Early assessment allows doctors to diagnose and treat gangrene before extensive tissue death and serious complications occur. When in doubt, seek medical advice.


Gangrene results in death of tissue. Prompt treatment is vital to stop its spread and prevent the following serious complications:


Bacterial infection can spread from the gangrene throughout the body causing sepsis, a life-threatening reaction. Sepsis can lead to shock, organ failure and death.


If gangrene is severe or spreads quickly, amputation of the dead tissue may be necessary. This may include removal of fingers, toes, hands, feet or limbs to prevent it advancing further.


Collections of pus called abscesses often form within or under the gangrenous tissue. Abscesses require drainage.

Blood Clots

Gangrene raises the risk of dangerous blood clots that can travel to the lungs (pulmonary embolism), heart or brain causing severe organ damage.


Gangrene in the abdomen and internal organs can lead to inflammation of the peritoneum, the membrane lining the cavity.

Toxic Shock Syndrome

Widespread bacterial infection from gangrene may cause toxic shock syndrome – a hazardous drop in blood pressure.

Necrotizing Fasciitis

Also called flesh-eating disease, this rare infection destroys muscle tissue and can occur if gangrene spreads from the skin deeper into the body.


Doctors diagnose gangrene based on the patient’s symptoms, medical history and the findings of certain diagnostic tests:

Physical Exam

The affected area is visually examined for signs like skin discoloration or open wounds. The doctor also checks for sensations, warmth and capillary refill.

Medical History

Current medical conditions and past illnesses that increase the risk for gangrene are identified. Family history may indicate a genetic risk.

Blood Tests

Blood tests check for elevated white cell count indicating infections, diabetes markers, and kidney function. Blood cultures may reveal bacteria.

Imaging Tests

Tests like CT scans, X-rays, MRI scans and ultrasound allow internal visualization of tissue damage and check for internal abscesses.

Tissue Biopsy

A small sample of tissue may be taken to test for bacteria and determine how far gangrene has spread into healthy tissue.


Treatment focuses on halting the spread of gangrene and preventing serious complications. Amputation of dead tissue may be required. Treatment options include:


Intravenous antibiotics are administered to treat bacterial infections causing infectious gangrene. Broad-spectrum antibiotics may be tried initially.

Wound Care

Gangrenous wounds require regular cleaning and debridement to remove dead tissue. Wet to dry dressings help remove slough. Oxygen therapy may promote healing.


Surgery is needed to remove gangrenous tissue and prevent spread. Amputation may be required for larger areas like digits or limbs. Damaged blood vessels may need repaired.

Hyperbaric Oxygen

Increasing oxygen levels to tissues with a specialized chamber can help treat stubborn gangrene wounds, especially in diabetics.

Intravenous Fluids

Fluids and electrolytes are given through IV to treat dehydration from infections and support circulation. Nutritional support may be needed.


In addition to antibiotics, medications to improve blood flow and treat pain may be prescribed. Blood thinners help avoid clots.


The following lifestyle measures and medical management can help prevent the onset of gangrene:

– Control diabetes through diet, exercise, medication, and regular screening

– Quit smoking and avoid secondhand smoke

– Exercise regularly and maintain healthy circulation

– Promptly treat foot and skin infections, ulcers or wounds

– Manage chronic health conditions like atherosclerosis

– Follow up regularly and control illnesses that weaken immunity

– Obtain preventative care like immunizations and cancer screenings

– Have prompt treatment for any bite wounds or animal bites

– Seek treatment for possible frostbite and avoid extreme cold

– Get blood flow restored quickly after injuries and trauma

– Take protective steps to avoid hand and foot injuries

– Request physician review of any medications that may increase gangrene risk


The outlook for gangrene depends on various factors like the location, size, presence of infection and speed of spread. Early diagnosis and prompt treatment are key. Mild cases treated quickly may lead to full recovery. However, extensive tissue death often leads to amputation. Even with treatment, gangrene can proven fatal in up to 15% to 20% of cases due to severe infections and complications. Strict follow up is necessary to monitor for recurrence.


Gangrene is a serious condition arising from interrupted blood flow or bacterial infections. It leads to decay and death of body tissue. Knowing how to identify the early warning signs like skin changes, numbness, blisters and pain enables prompt diagnosis and treatment. Left untreated, gangrene spreads rapidly leading to serious complications such as sepsis, amputations and even death. However, quick medical attention can often halt its progression and restore circulation to salvage the affected area. Lifestyle measures and proactive health management are key for prevention, especially in high-risk groups. Increased awareness of gangrene leads to better outcomes. Patients should educate themselves on its causes, symptoms and risk factors to allow for the earliest possible intervention.

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