The Dermatology Blog

A young woman asked me this week why she bruises so easily on her legs. I get this question in clinic (as well as at my dinner table) a lot.

A bruise appears when you injure a superficial blood vessel and blood leaks into the tissues just beneath the surface. The leaked red blood appears as blue-black through the skin. The size of the bruise depends on how much blood leaked out before a clot formed to stop the bleeding — the larger the vessel damaged or the longer it takes for your blood to clot, the larger the bruise will be.

As the pooled blood resolves over days, hemoglobin, the iron-containing structure that absorbs oxygen in red blood cells, is broken down into its component parts, bilirubin and biliverdin. Biliverdin has a green color; this is why bruises change from blue-black to yellow-green over time. It usually takes two to four weeks for the blood cells to be reabsorbed completely. Bruises on the face or upper body resolve more quickly than bruises on the legs because of differences in blood supply.

It is true that women bruise more easily than men. This is most noticeable on their legs and buttocks. As many women will tell you, sometimes even an insignificant bump or injury can cause an obvious black and blue.

Easier bruising in women is probably because women’s skin is thinner (though not the women in my family…) and because the fat and blood vessels in their skin is organized a little differently compared to men. The dense collagen layer is thicker in men and the blood vessels are held more securely. Similarly, structural differences between men’s and women’s skin can be seen in things like cellulite (which you’ll notice men don’t have, even when they’re overweight).

Bruising is common and is usually normal, but in uncommon instances it can be a marker for serious medical conditions such as bleeding disorders, low platelets or other blood disorders, or liver disease. If you have any concern, as always, consult your physician.

In addition to being female, bruising easily results when your blood vessels are made vulnerable, as when the skin has been thinned from:

• Aging
• Sun Damage (especially on the forearms)
• Oral or Topical Steroids

Easy bruising also occurs when the blood is prevented from clotting quickly, as from:

• Aspirin
• Ibuprofen, Naproxen
• Plavix
• Coumadin (warfarin)
• Fish oil
• Vitamin E
• Garlic
• Ginger
• Ginko biloba

So if you do whack your previously pristine shin on the coffee table, what can you can do to minimize the bruise?

• Apply ice for 10 to 20 minutes. This slows the blood flow and minimizes the amount of blood leaking into the skin.
• Keep the leg elevated. This also minimizes the effect that gravity has on pooling blood in your legs.
• After a day or so apply warm compresses which can help the bruise to resolve more quickly.
• Finally, eat plenty of blueberries or broccoli for vitamin K; citrus for vitamin C; eggs, dairy, meat, or fish for vitamin B12; and leafy green vegetables for folic acid. All of these vitamins are needed for good blood clotting and healing.