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Hemophilia refers to a group of bleeding disorders in which blood clotting takes a long time.

There are two forms of hemophilia:

Alternative Names

Hemophilia A; Classic hemophilia; Factor VIII deficiency; Hemophilia B; Christmas disease; Factor IX deficiency


When you bleed, a series of reactions take place in the body that helps blood clots form. This process is called the coagulation cascade. It involves special proteins called coagulation, or clotting factors. You may have a higher chance of excess bleeding if one or more of these factors are missing or aren't functioning like they should.

Hemophilia is caused by the lack of clotting factor VIII or IX in the blood. In most cases, hemophilia is passed down through families (inherited). Most of the time, it is passed to male children.


The main symptom of hemophilia is bleeding. Mild cases may not be detected until later in life, after excessive bleeding following surgery or an injury.

In the worst cases, bleeding occurs for no reason. Internal bleeding may occur anywhere and bleeding into joints is common.

Exams and Tests

Most often, hemophilia is diagnosed after a person has an abnormal bleeding episode. It can also be diagnosed by a blood test done to detect the problem, if other family members have the condition.


The most common treatment is to replace the missing clotting factor in the blood through a vein (intravenous infusions).

Special care during surgery needs to be taken if you have this bleeding disorder. So, be sure to tell your surgeon that you have this disorder.

It is also very important to share information about your disorder with blood relatives as they may also be affected.

Support Groups

Joining a support group where members share common issues can relieve the stress of a chronic disease.

Outlook (Prognosis)

Most people with hemophilia are able to do normal activities. But some people have bleeding into the joints, which may limit their activity.

A small number of people with hemophilia may die of severe bleeding.


Carcao M, Moorehead P, Lillicrap D. Hemophilia A and B. In: Hoffman R, Benz EJ Jr, Silberstein LE, Heslop HE, Weitz JI, Anastasi JI, eds. Hematology: Basic Principles and Practice. 6th ed. Philadelphia, PA: Elsevier Saunders; 2013:chap 137.

Ragni MV. Hemorrhagic disorders. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 174.

Version Info

  • Last reviewed on 2/13/2015
  • Rita Nanda, MD, Assistant Professor of Medicine, Section of Hematology/Oncology, University of Chicago Medicine, Chicago, IL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

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