They may also be purpura, bruise-like marks which are not caused by injury, or petechiae, which vary in shade and are smaller versions of purpuras. Such dots may be caused by medicines such as aspirin, an infection which causes a build-up of toxin in blood or tissues, a bleeding disorder such as haemophilia, or diseases which cause clotting. These illnesses include lupus, cirrhosis and some cancers.
Malnutrition, such as a deficiency in Vitamins B12 or C or folic acid, can also introduce such spots under the skin. Understandably, medical treatment for abnormal bruising or blood spots focuses on preventing or stopping bleeding, changing or adjusting a medicine that may be causing the bruising, or treating the medical problem that is causing the bruising.
If the skin is injured over a bruise, be sure to watch for signs of a skin infection. If you notice anything alarming about the dots, and they appear all over the body and not in one isolated place, do consult a physician who will advise you on the best course of action.