Bruises occur when something damages small blood vessels in the skin. Bruises typically change color as they heal, at first appearing red, purple, or darker than the surrounding skin. They may progress to blue, black, or green before fading.
Bruising typically occurs when a person receives an injury to an area of their skin, such as from falling or bumping into something.
The blood vessels between the skin and other tissues in the body burst. The blood pools under the surface of the skin, causing a bruise. It is natural for a bruise to change color during the healing process.
This article explains the usual bruising cycle and when a person should contact a doctor about a bruise.
Bruise colors depend on factors such as the intensity of an injury, the location on the body, and a person’s skin tone.
A person may be able to estimate how old a bruise is from its color. As the body heals and breaks down the hemoglobin, the compound that gives blood its red color, the bruise will change color. This is a regular part of the healing process.
Skin color affects the appearance of bruises. An older 2013 study suggested that people with medium skin tones may have more red and yellow in their bruises than people with lighter or darker skin tones. Bruises on darker skin tones appear darker and have fewer noticeable color changes than those on lighter or medium skin tones.
During the healing process, a bruise will usually go through the following color changes:
- Within 24 hours of an injury: A bruise often starts red because fresh, oxygen-rich blood pools underneath the skin. Darker skin may not show noticeable reddening but may appear darker.
- After 1–2 days: The blood begins to lose oxygen and change color. A bruise that is a few days old will often appear blue, purple, black, or slightly darker than unbruised skin.
- After 5–10 days: On lighter and medium skin tones, the bruise may turn yellow or green. These colors come from compounds called biliverdin and bilirubin, which the body produces when it breaks down hemoglobin. On darker skin, bruises may lighten in color.
- After 10–14 days: On lighter skin tones, a bruise may turn yellowish-brown or light brown. On darker skin tones, a bruise will fade gradually.
Most bruises will disappear without treatment within about 2 weeks.
Learn more about bruising on darker skin.
Bruises are typically surface injuries that do not require medical attention. However, sometimes, a person may need to seek medical attention for their bruising.
When a hematoma occurs, the body cannot heal the bruise as easily or quickly as a smaller bruise. As a result, a hematoma stays the same color and firmness and is painful even after several days.
A person may need medical attention to determine whether the hematoma requires further treatment.
In most cases, bruises heal without treatment within 2 weeks. In some cases, a doctor may need to investigate bruising further.
A person with bruising may need to consult a doctor if they:
- lose function of a joint or limb
- experience repeated bruising without a known cause
- may have a broken bone
- have bruising on the head or neck and difficulty breathing
- have bruising around the eye
- are on blood-thinning medication or have a blood-clotting disorder
People taking prescription blood thinners, such as warfarin, should notify their doctor if they experience any falls or significant injuries.
In rare cases, bruising can indicate more serious conditions, including:
Bruises change color as the body heals from an injury. On lighter and medium skin tones, bruises may change from red to blue and black, or green and yellow. On darker skin, bruises may be less noticeable and appear as darker areas of brown or black that gradually become lighter.
If a bruise does not fade, worsens, or other issues accompany it, a person should consult a doctor. Otherwise, most bruises heal within 2 weeks without medical treatment.