If you think you'd let a bruise heal by itself, think again.

I have a friend who once accidently bumped her thigh into the edge of the window sill. Thinking it was just a small bruise, she left it alone. After an hour or so, she felt an aching sore at the injured area and as she inspected it, the bruise swelled to almost palm size.

A few days later, she went to see a doctor and was diagnosed with kidney failure.

We often pay no attention to our bruises and think they can be rubbed off or healed with some cream from the pharmacy. But some bruises can be life-threatening. Below are a few questions on bruises:

What is a bruise?
A bruise is caused when tiny blood vessels are damaged or broken as the result of a blow to the skin. The raised area of a bump or bruise results from blood leaking from these injured blood vessels into the tissues as well as from the body's response to the injury.

Why do some people bruise more easily than others?
Age - an elderly person will tend to bruise more easily than a child because blood vessels become more fragile as we age.

Medications that interfere with blood clotting, causing more bleeding into the skin or tissue. Examples - non-steroidal anti-inflammatories (e.g., ibuprofen/Advil, Nuprin and naproxen/Aleve), over-the-counter medications (e.g., aspirings), Warfarin (Coumadin), Cortisone medications (e.g., prednisone) promote bruising by increasing the fragility of the tiny blood vessels in the skin.

How long will it take for a bruise to heal?
2 - 3 weeks for the skin to return to normal.

What if the bruise doesn't go away or starts to swell?
There are two cases for this. The first case is known as Hematoma (a large collection of blood is formed under the skin or in the muscle, instead of trying to clean up the area, the body may wall the blood) and the second is know as heterotopic ossification or myositis ossificans (occurs when the body deposits calcium). These two conditions have to be diagnosed by X-Ray.

What are the different types of bruising?
Petechiae - very small, one to three millimeter, accumulations of blood beneath the skin. These can appear like multiple tiny red dots on any part of the body (most commonly the legs). These are often multiple and can suggest a serious health problem. Examples of these are an infection of the valves of the heart or abnormal function of the blood clotting elements.

Bruising around the naval - bleeding in the abdomen

Bruising behind the ear - can suggest a skull fracture

Raised, firm bruises - can be multiple. Can be a sign of various types of "autoimmune" diseases (diseases in which the body attacks its own blood vessels).

The most effective way to treat bruises is to ice it. Pack some ice into a bag and wrap it with a towel. Do not apply the ice directly to the infected area as this can cause frost bite. Apply the ice (wrapped with a towel) to the injured area and repeat this two times a day. If possible, elevate your leg to above the heart level. This will reduce the bleeding and swelling. Apply pressure to the area by hand while rubbing cream recommended by your local pharmacy.