Getting easily bruised - Do I need to get checked?

Dear Ask The Doctor: BLACK AND BLUE BRUISE APPEARS ON UPPER LEFT ARM, TAKE ABOUT A WEEK TO GO AWAY FEW WEEKS LATER IT APPEARS ON MY LEFT THIGH, THIS HAPPENS EVERY FEW MONTHS WAS TOLD TO GET MY PPT CHECKED OUT. IS THIS TRUE. DOES NOT COME FROM ANY INJURY

Dear ANTOINETTE: Getting easily bruised is common with age. Although most bruises are harmless and go away without treatment, easy bruising can sometimes be a sign of a more serious problem. Bruises form when small blood vessels (capillaries) near the skin's surface are broken by the impact of a blow or injury — often on the arms or legs. Some people — especially women — are more prone to bruising than are others. As you get older, several factors can contribute to easy bruising, including: aging capillaries and thinning skin. However in some cases these signs and symptoms can indicate low levels of or abnormally functioning platelets. To diagnose the cause of your bruising, your doctor might check your blood platelet levels or do tests that measure the ability of your blood to clot.