Thanks for the question.
In cases of unexplained bruises without any trauma one needs to investigate the coagulation status of the blood. Usually these kind of bruises occur due to subcutaneous tiny hemorrhages.There can be various causes which can cause such hemorrhages.I think you should see a physician to get clinical examination done.The doctor may initially want to check your platelet count
, bleeding and clotting time.Rather than anemia
low platelet count is more likely cause of such bruises.