What is the Difference Between Bruising and Necrosis

Bruising and necrosis are two different skin conditions that involve skin discoloration and pain. Understanding the difference between bruising and necrosis is essential for accurate diagnosis and appropriate medical management.

The key difference between bruising and necrosis is their cause. Bruising is a skin injury which occurs due to damaged blood cells accumulating under the skin while necrosis is the death of body tissues due to the tissue not having or receiving enough blood supply.

CONTENTS

1. Overview and Key Difference
2. What is Bruising  
3. What is Necrosis
4. Similarities Between Bruising and Necrosis
5. Bruising vs Necrosis in Tabular Form
6. Summary – Bruising vs Necrosis
7. FAQ – Bruising and Necrosis

What is Bruising?

Bruising is a common skin injury that results in skin discoloration, typically occurring due to the accumulation of damaged blood cells beneath the skin. It often presents as a black or blue mark. Symptoms of this condition may include an initial reddish mark that later turns blue or dark purple, accompanied by pain, and during the healing process, the bruise may transition to yellow or green. Bruising can be caused by tiny tears in the blood vessels under the skin, bleeding disorders, or the use of blood thinners.

Diagnosis of bruising typically involves a medical history review and physical examination. Treatment options may include initially applying a cold compress to the affected area, elevating the limb in the case of larger bruises, using warm compresses after two days, taking painkillers such as acetaminophen, and applying vitamin K and aloe vera to promote healing.

What is Necrosis?

Necrosis is the death of body tissues that occurs when the tissue lacks adequate blood supply. When necrosis affects a larger area, it is referred to as gangrene. Symptoms of necrosis may include severe pain, fever, rapid heartbeat, numbness or pain extending beyond the wound, rapidly spreading redness from the wound, warmth near the wound, skin blisters, a crackling sensation under the skin, grayish, foul-smelling liquid draining from the wound, difficulty thinking clearly, and excessive sweating. Necrosis can be caused by hypoxia (lack of oxygen), physical agents such as trauma, frostbite, radiation, or electric shock, chemical agents like poison, recreational drugs, or occupational exposure, as well as by fungi, bacteria, viruses, or immunologic reactions.

Diagnosis of necrosis typically involves physical examination and imaging tests such as X-rays, MRIs, bone scans, and biopsies. Treatment options for necrosis may include surgery to restore blood flow and remove damaged tissues, antibiotics to prevent infections and management of the initial cause, such as burns or other injuries.

Similarities Between Bruising and Necrosis

1. Bruising and necrosis are two different skin conditions.
2. Both bruising and necrosis involve skin discoloration and pain.
3. Both can be diagnosed through physical evaluation.
4. They can be treated through pain-relieving medications and therapies.

Difference Between Bruising and Necrosis

Definition

a. Bruising is a common skin injury that causes skin discoloration.
b. Necrosis is the death of body tissues, which occurs when the tissue lacks adequate blood supply.

Causes

a. Bruising can be caused by tiny tears in the blood vessels under the skin, bleeding disorders, or the use of blood thinners.
b. Necrosis can be caused by hypoxia (lack of oxygen), physical agents such as trauma, frostbite, radiation, or electric shock, chemical agents like poison, recreational drugs, occupational exposure, fungi, bacteria, viruses, or immunologic reactions.

Symptoms

a. Bruising may present as an initial reddish mark that turns to blue or dark purple later, accompanied by pain, and during healing, it may turn yellow or green.
b. Necrosis symptoms may include severe pain, fever, rapid heartbeat, numbness or pain extending past the wound, rapidly spreading redness from the wound, pain, and warmth near the wound, skin blisters, a crackling sensation under the skin, grayish, foul-smelling liquid draining from the wound, difficulty thinking clearly, and excessive sweating.

Diagnosis

a. Bruising can be diagnosed through a medical history review and physical examination.
b. Necrosis diagnosis typically involves physical examination and imaging tests such as X-rays, MRIs, bone scans, and biopsies.

Treatment

a. Treatment for bruising may include initial application of a cold compress to the affected area, elevation of the limb in the case of larger bruises, warm compresses after two days, taking painkillers such as acetaminophen, and applying vitamin K and aloe vera.
b. Treatment for necrosis may involve surgery to restore blood flow and remove damaged tissues, antibiotics to prevent infections, and management of the initial cause, such as burns or other injuries.

The infographic below presents the differences between bruising and necrosis in tabular form for side-by-side comparison.

Summary – Bruising vs Necrosis

Bruising and necrosis are two different skin conditions that involve skin discoloration and pain. Bruising is a common skin injury that can be seen as skin discoloration while necrosis is the death of body tissues. Fresh bruises normally appear reddish, and they are initially uncomfortable and painful. Later, it turns blue or purple. The symptoms of necrosis are pain, the affected area feeling cool due to lack of blood supply, abnormal sensations such as tingling or burning, numbness, skin discoloration, and blisters filled with clear liquid or blood. Furthermore, bruises get better after a few days, while necrosis has no cure other than removing the necrotic tissue. Thus, this summarizes the difference between bruising and necrosis.

FAQ: Bruising and Necrosis

1. What are the three signs and symptoms of bruises?

• Blood accumulates in areas under the skin, resulting in pain, swelling, and skin discoloration. The main symptoms of a bruise are pain, swelling, and skin discoloration (red, blue, or purple).

2. How to get rid of bruises?

• Elevate the bruised area above heart level, apply an ice pack wrapped in a thin towel and leave it in place for 20 minutes, cover the swollen area, and put an elastic bandage around it tightly. If the bruised area is swelling, apply an elastic bandage, but not too tightly.

3. Does a bruise look like necrosis?

• Bruises and necrosis may have similar skin discoloration. However, skin necrosis specifically appears tan, brown, or black and has a thick, dry, and leathery appearance. A bruise is initially red but may later appear as a black or blue mark.

4. What do you mean by necrosis?

• Necrosis is the death of body tissues due to a lack of blood supply, which cannot be reversed. Large areas of necrosis are known as gangrene. Necrosis can only be treated through specific surgeries that remove the necrotic tissues.

5. What does the start of necrosis look like?

• At the start, necrosis appears as a reddish, swollen area on the skin with skin blisters, abnormal sensations such as tingling, burning, or numbness, and a grayish, foul-smelling clear liquid or blood that drains from the wound.

Reference:

1. “Bruises (Ecchymosis): Symptoms, Causes, Treatment & Prevention.” Cleveland Clinic.
2. Jennifer Whitlock, RN. “Necrosis: What You Should Know.” Verywell Health.

Image Courtesy:

1. “Bruising on back from Cupping” By Amy Selleck from Portland, OR, USA – Bruised Back from CuppingUploaded by SchuminWeb (CC BY 2.0) via Commons Wikimedia
2. “Necrotic leg wound” By derivative work: Chaldor (talk)Rowland_recluse_bite.jpg: Jeffrey Rowland from Easthampton, MA, USA (CC BY 2.0) via Commons Wikimedia