Someone who has leukemia might also witness red spots on their skin. These are pretty tiny red spots of blood called petechiae, and they appear as red spots on light skin, and on darker skin, it's less noticeable.  It's most likely to occur where blood is likely to accumulate, like on your hands, feet, and arms. The red spots are caused by tiny broken blood vessels, called capillaries, under the skin. Usually, platelets help your blood clot, but for someone with leukemia, the body doesn't have enough platelets to do so.