Within seconds of an injury, tiny cells in the blood, called platelets, bunch together around the wound. Blood proteins, platelets, calcium and other tissue factors react together and form what's called a clot, which acts like a net over the wound. Over the next several days to weeks, the clot strengthens, then dissolves when the wound is healed.

In people with bleeding disorders, clotting factors are missing or don't work as they should. This causes them to bleed for a longer time than those whose blood factor levels are normal. It's a myth that persons with bleeding disorders bleed to death from minor injuries or their blood flows faster. Bleeding problems can range from mild to severe.

Symptoms include:

• Excessive bleeding
  
• Excessive bruising
  
• Easy bleeding
  
• Nose bleeds
  
• Abnormal menstrual bleeding

Bleeding disorder risks include:

• Scarring of the joints or joint disease
  
• Vision loss from bleeding into the eye
  
• Chronic anemia from blood loss. Anemia is a low red blood cell count
  
• Neurologic or psychiatric problems
  
• Death, which may occur with large amounts of blood loss or bleeding in critical areas, such as the brain.

Causes
Some bleeding disorders are present at birth and are caused by rare inherited disorders. Others are developed during certain illnesses (such as vitamin K deficiency, severe liver disease), or treatments (such as use of anticoagulant drugs or prolonged use of antibiotics). They can include hemophilia and other very rare blood disorders. There are many causes of bleeding disorders, including:

• von Willebrand's disease , which is an inherited blood disorder thought to affect between 1% and 2% of the population
  
• Immune system-related diseases, such as allergic reactions to medications, or reactions to an infection
  
• Cancer, such as leukemia, which is a blood cancer
  
• Liver disease
  
• Bone marrow problems
  
• Disseminated intravascular coagulation, which is a condition often associated with child bearing, cancer, or infection, in which the body's clotting system functions abnormally
  
• Pregnancy-associated eclampsia, also known as severe toxicity of pregnancy
  
• Antibodies, a type of immune system protein, that destroy blood clotting factors
  
• Medicines, such as aspirin, heparin, warfarin, and drugs used to break up blood clots 

Congenital bleeding disorders are very rare, and with the exception of hemophilia and von Willebrand disease, education about them has not been a priority of the medical community. Most have only been discovered and described in the past few decades.