You must first answer the question as to what you mean by "strange".. If it means that there was no history of trauma to cause a bleeding under the skin then such bruises can be spontaneous (without injury) bleeding due to impairment of blood clotting mechanisms or tiny obstructions of tiny blood vessels.. Sometimes bruises may occur from a minor bump or rub to the skin especially in the elderly that the original injury is unrecognized and then not recalled and therefore might be considered as "strange". Sometimes folks are born with vascular birthmarks which may consist of macular stains (salmon patches), hemangiomas, and Port-wine stains. These may look like bruises, "strange bruises" but really are not bleeding but abnormal collections of blood vessels under the skin. These generally do not disappear with time as with a traumatic bruise. So the question again to the Medpedia visitor is "what do mean by 'strange'?" ..Maurice..