What causes bruising?

Bruises occur when blood comes out of blood vessels into the skin or just below the skin's surface. Bruises can occur from a fall, accident, sports injury or medical procedure. 

"Everyone experiences bruising, but they are more common in older people," says dermatologist Ronald Sulewski, MD. "There are also some bleeding disorders and medical conditions that can make you more prone to bruising." 

What do bruises look like? 

Bruises typically show up as red or purple dark spots or patches. They can change into various colors, including yellow, orange and green, as they evolve over a week or so. 

"These changing colors in the skin are the result of hemoglobin being broken down by the body," Dr. Sulewski explains. "Hemoglobin is the protein that carries oxygen to our tissues in our blood."

How do bruises heal? 

Bruises heal as the body's immune system (white blood cells) breaks down the blood in the skin and under the skin over time. 

"Bruises can itch as they are healing because the body's immune system is breaking down the bruise," says Dr. Sulewski. "The white blood cells use chemical signaling that can lead to itching."

Can bruising cause blood clots or swelling? 

Visible bruising in the skin is a superficial process. Signs of other deeper blood clots are usually swelling of the tissue and pain.

"Bruising can cause swelling, especially if more blood is present than the average bruise," says Dr. Sulewski. "Sometimes patients get hematomas, which are larger and deeper than a bruise." 

Hematomas can be painful and swollen and can affect internal organs. They may require medical attention.

How can I help my bruise go away?

Most bruises will resolve within a week or two without treatment. Severe bruising and hematomas can last for a month or longer. To heal faster, you can:

• Rest and elevate the injured area to reduce swelling and relieve pain
• Apply ice packs for the first 24 to 48 hours after injury
• Apply a heating pad or warm compress to the injured area after two days
• Take over-the-counter pain medication, such as acetaminophen (Tylenol). Check with your doctor before using nonsteroidal anti-inflammatory drugs (NSAIDs) like Advil or Aleve 

Why do I bruise so easily?

Many things can cause frequent bruising. Most of these causes aren't serious and don't require treatment. You should discuss with your doctor to pinpoint what is causing your frequent or unexplained bruising. 

Things that may cause you to bruise more easily include:

• Medications to thin blood/prevent clotting, like aspirin or blood thinners
• NSAIDs such as ibuprofen or naproxen
• Use of steroids, such as prednisone
• Past excessive sun exposure
• Low blood platelet count
• Vitamin C or vitamin K deficiency 
• Bleeding disorders 
• Medical conditions like cancer or liver disease

When should I see a doctor about my bruise?

"If you have a bruise that doesn't go away, it might actually be a skin lesion rather than a bruise," explains Dr. Sulewski. "If your bruise remains for more than a month or is extremely painful or swollen, you should have it checked by your doctor." 

Also, if you have multiple, unexplained bruises or a bruise that keeps returning to the same area, your doctor may order tests to pinpoint the cause. Tests may include X-rays to check for bone fractures and blood tests to check for clotting disorders and vitamin deficiencies.