A bruise develops when an injury does not break the skin’s surface but still causes small blood vessels just below the surface to break, leaking blood into the surrounding tissue.
Bruises are also called contusions.
Most bruises heal without medical treatment, and it is normal for a bruise to change colors and even itch during this process.
A bruise will look different according to a person’s skin color and may be more difficult to identify on darker skin. In general, bruises appear as discolored or darker patches on the skin.
Learn more about how to identify bruises on darker skin here.
Bruises can look red or purple when they first appear, changing to yellowy-green as they heal. This is the time when bruises may start itching.
Muscles and bones can bruise, too. Bruises can cause the surrounding areas to become swollen, stiff, and sore. A bruised muscle may cause reduced motion, while more severe bruises, or hematomas, can cause a raised, swollen, and painful bump to form.
Researchers have not determined why some bruises itch. Contributing factors can include dry skin and the healing process itself.
Dry skin is often itchy. If people with dry skin develop a bruise, the area can become very sensitive and painful. If a person does not moisturize the dry skin where the bruise is, the bruise might become itchy.
Older adults may be particularly vulnerable to itchy bruises since they tend to bruise more easily and are more likely to have dry skin.
Long-lasting bruises on the hands and arms are called actinic purpura.
Most often seen in older adults, actinic purpura typically develop due to thin skin, weakened blood vessels, and the use of steroids and blood thinners, such as coumadin and alcohol. People with dry skin may develop itchy bruises.
Bruises are a type of wound known as a pressure wound. According to a 2015 article, itching is a typical healing response for all types of wounds.
Experts say histamine, which the body releases as a wound heals, and high bilirubin levels, which can also increase as wounds heal, can cause itching.
Sometimes, bruises develop as a result of an itch. For example, some people are so sensitive to bites from mosquitos, bed bugs, or other pests that they scratch hard enough to give themselves bruises.
An itchy bruise is usually not a sign of infection.
Experts list increasing pain and swelling, expanding discoloration of the skin, pus, and feeling sick as key signs of wound infection. They do not mention itching as a sign.
According to the American Cancer Society, itching can have associations with severe illnesses, such as leukemia, cancer of the blood cells. However, when a person has leukemia or another blood cancer, they typically experience itching over their whole body, not just one spot. A person cannot trace this kind of itching back to a rash, bruise, or dry skin.
The basic treatment for bruises, whether they itch or not, involves:
- resting and elevating the bruised area if possible and comfortable
- icing the site in the first 2 days after the injury
- applying heat to the injury after 48 hours
- taking over-the-counter (OTC) pain relief medication, if needed
Further treatment can benefit an itchy bruise:
- washing the bruised area with warm, not hot, water
- using gentle, non-irritating soap
- applying soothing lotions to treat dry skin and calm the itch
- taking OTC antihistamines, if needed
People who have what appears to be an itchy bruise but have no apparent reason for a bruise may have a skin condition that causes a rash.
For example, skin conditions, such as eczema or atopic dermatitis can cause rashes that are so itchy that people bruise themselves while scratching or rubbing.
The condition can also cause the skin to discolor over time, so the affected area looks more like a bruise than a rash.
Psoriasis is another common skin condition. According to the National Psoriasis Foundation in 2014, more than 8 million people in the United States had psoriasis. Psoriasis can cause itchy scales to develop anywhere on the body, particularly the knees, elbows, and scalp.
When People of Color have psoriasis, their plaques tend to be purple, grayish, or darker brown and may look more like bruises than psoriasis plaques.
The majority of bruises heal without medical treatment. Indications that it may be time to contact a doctor for treatment include:
- frequently bruising with no apparent reason
- having a bruise that lasts for more than 2 weeks without much improvement
- developing signs of infection, such as increasing redness or swelling, around the bruise
Experiencing significant pain or pressure in the injured area may signify a serious condition called compartment syndrome, which requires prompt medical treatment.
Bruises are very common injuries that generally heal on their own without medical treatment.
During the healing process, it is normal for bruises to change color, and some people may experience itching as well.
Experts have not determined one particular cause for itchy bruises, although dry skin and the natural healing process may be factors.
Some skin conditions, such as eczema or psoriasis, may cause rashes that people might confuse with bruises.
It is also possible for people to develop bruises after intensely scratching their skin due to another condition, such as an insect bite or eczema.
Anyone who experiences bruising that seems unusual, infected, or very painful, see a healthcare professional.