Blood spots under the skin may be either purpura or petechiae. Purpura might look like bruises, but they are not caused by an injury as most regular bruises are. Petechiae don’t look like bruises. They are tiny, flat, red or purple spots in the skin, but they are different than the tiny, flat, red spots or birthmarks (hemangiomas) that are present all the time.
Sudden unexplained bruising or blood spots under the skin or a sudden increase in the frequency of bruising may be caused by:
* A medicine, such as aspirin or blood thinners (anticoagulants).
* Infection that causes the buildup of toxin in the blood or tissues (sepsis).
* A bleeding or clotting disorder, such as hemophilia, von Willebrand’s disease, thrombocytopenia, or another less common bleeding or clotting disorder.
* Other diseases that affect clotting. Examples include:
o Chronic inflammatory diseases, such as lupus.
o Liver disease, such as cirrhosis.
o Some types of cancer, such as Hodgkin’s disease, leukemia, or multiple myeloma.
* Inflammation of a blood vessel (vasculitis).
* Malnutrition, such as deficiencies of vitamins B12, C, or K, or folic acid.
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.