First Aid & Emergencies

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:
  • Chronic inflammatory diseases, such as lupus.
  • Liver disease, such as cirrhosis.
  • 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.

If the skin is injured over a bruise, be sure to watch for signs of a skin infection.

Check your symptoms to decide if and when you should see a doctor.