A bruise, medically known as a contusion, is a common skin discoloration that occurs when tiny blood vessels beneath the skin’s surface are damaged. This causes blood to leak into surrounding tissues. As the body works to repair itself, many individuals notice an itching sensation around the bruise, which can be part of the healing process.
How Bruises Form and Heal
Bruises develop when small blood vessels, called capillaries, rupture, allowing blood to seep into the soft tissues under the skin. This pooling of blood becomes visible as a discolored mark. The initial appearance of a bruise is often reddish, due to the fresh, oxygenated blood beneath the skin.
Over a few days, the bruise undergoes color changes as the body breaks down and reabsorbs the trapped blood. Within one to two days, the bruise may turn blue, purple, or black as the blood loses oxygen. Around five to ten days after the injury, the bruise often appears green or yellow. These green and yellow hues result from the breakdown of hemoglobin, the protein in red blood cells, into compounds like biliverdin (green) and bilirubin (yellow). Eventually, the bruise fades to yellowish-brown or light brown before disappearing as these pigments are reabsorbed.
The Science Behind the Itch
The itching sensation experienced during bruise healing has several contributing factors. One reason for the itch is the release of histamine. As the body repairs itself to clear cellular debris and reabsorb leaked blood, inflammatory chemicals are released. Histamine, a compound involved in immune responses, can trigger nerve endings, leading to an itchy feeling.
Another factor contributing to itch is the regeneration of nerve endings. When blood vessels are damaged during bruise formation, nearby nerve fibers can also be affected. As these nerves repair and new ones form during healing, they can become hypersensitive. This heightened sensitivity can transmit itch signals to the brain.
Dry skin can also exacerbate the itching sensation over a healing bruise. The skin covering an injured area might become dry, especially if the bruise is large or located over a joint where the skin stretches. Dry skin itself is prone to itching, and this dryness can intensify the itchiness from the healing process.
Soothing Itchy Bruises
Managing the discomfort of an itchy bruise involves several practical approaches. Keeping the skin adequately moisturized can help alleviate dryness, which often contributes to the itch. Applying a fragrance-free moisturizer regularly can prevent the skin from becoming overly dry and irritated.
Avoiding scratching the bruise is important, as it can further irritate the skin, potentially leading to more damage or infection. Applying a cool compress to the itchy area can provide temporary relief by numbing the nerve endings and reducing inflammation. Wearing loose-fitting clothing over the bruised area can also prevent irritation from friction.
Over-the-counter anti-itch creams containing ingredients like hydrocortisone or pramoxine can also be effective. These creams can help reduce inflammation and calm the itching sensation. Calamine lotion is another option that can offer soothing relief for mild itchiness.
When to Be Concerned
While an itchy bruise is typically a normal part of the healing process, certain signs warrant medical attention. Consult a healthcare provider if a bruise appears without a known injury, especially if it is large or frequently occurs. A doctor should also be consulted if the bruise is unusually painful, growing rapidly, or accompanied by a noticeable lump, which could indicate a hematoma.
Signs of infection, such as increasing redness, pus or fluid draining from the bruise, warmth to the touch, or a fever, require prompt medical evaluation. Additionally, if the bruise does not show signs of improvement or fade within two to three weeks, or if the itching is severe, persistent, or accompanied by other concerning symptoms like unexplained bleeding elsewhere, seek medical advice.