Hemophilia

Medically reviewed by Drugs.com. Last updated on Jun 10, 2025.

What is hemophilia?

Hemophilia is an inherited disorder. It prevents blood from clotting properly. People with hemophilia bleed longer than usual. This bleeding can range from mild to severe. In severe cases, people with hemophilia can bleed to death.

Because of how they are inherited, the most severe and common types of hemophilia affect men far more often than women.

Clotting is the process in which the blood thickens or congeals. This prevents a cut or other injury from bleeding endlessly. Clotting factors are substances in the blood that help the blood to clot. People with hemophilia do not have enough clotting factors.

Blood clotting involves two systems:

• Platelets: these are specialized blood cells made in the bone marrow.
• The coagulation system: coagulation is a coordinated series of chemical reactions regulated by clotting factors that create clots that stop bleeding.

The main clotting factors involved in hemophilia are Factor VIII, Factor IX, and Factor XI.

There are several types of hemophilia:

• Hemophilia A is the most common type. People with hemophilia A do not have enough Factor VIII. Up to 70% of people with hemophilia A have severe disease, manifested by spontaneous bleeding or significant bleeding after minor injury.
• Hemophilia B is also known as Christmas disease. It is caused by a deficiency in Factor IX. Hemophilia B is severe in about a third of cases.
• Hemophilia C is caused by Factor XI deficiency. It is uncommon in the United States and tends to be less severe than Hemophilia A or Hemophilia B. It is inherited differently than Hemophilia A or B and, as a result, it can be passed to both male and female children.

The severity of disease varies depending on how low the affected factor level is. Hemophilia A and B can be mild, moderate, or severe while Hemophilia C is rarely severe.

Symptoms of hemophilia

People with hemophilia may bleed anywhere in the body. However, they seldom bleed significantly from small cuts or puncture wounds (such as having a blood test).

Rather, hemophiliacs bleed more than other people do from significant injuries, trauma, or surgery. How badly and how often people bleed directly relates to how much clotting factor they have.

People with hemophilia may experience:

• bleeding into the joints: The joints are the most common place for bleeding to occur. The ankle, hip, knee, or elbow joints are most commonly affected. The affected joint becomes warm, painful, and swollen. The person is not able to move the joint as freely as before. This can happen after an injury or without any cause.
• bleeding into muscle
• bleeding into the esophagus, stomach, or intestine
• bleeding into the urine
• bleeding from the nose and gums
• heavy menstrual bleeding (in women).

A less common but more serious complication is bleeding into the brain. Symptoms include sudden nausea, headache, and decreased mental awareness.

Symptoms of factor XI deficiency usually appear only in people who inherit the disease from both parents. Symptoms can include:

• prolonged and/or excessive bleeding after cuts, surgery, or dental extractions
• nosebleeds
• blood in the urine
• abnormally heavy or prolonged menstrual bleeding.

In hemophilia C, bleeding without any cause is rare.

Diagnosing hemophilia

People with severe hemophilia often develop bleeding problems within the first two years of life. Many infants are diagnosed when they have bleeding during delivery or prolonged bleeding after circumcision. Others are diagnosed in childhood. They may develop excessive bruising and bleeding into joints after typical childhood injuries.

People with mild hemophilia may not be diagnosed for decades. The diagnosis may be made only after they experience abnormal bleeding after trauma, injury, or surgery.

If your doctor suspects that you have hemophilia, he or she will ask how often you bleed and how severely. Your doctor will also ask if anyone in your family has a bleeding problem.  

Your doctor will examine you. He or she will focus on evidence of past bleeding into the skin, muscles and joints.  

A variety of blood tests will show if your blood has a clotting defect. The diagnosis of hemophilia A or B or factor XI deficiency can be confirmed by measuring the amount-specific clotting factors and genetic testing.

Expected duration of hemophilia

Hemophilia is a lifelong illness. Symptoms usually can be controlled with proper medical treatment.

Preventing hemophilia

People with a family history of hemophilia can learn their risks of passing hemophilia to their children. A simple blood test is usually all that is necessary. 

People with hemophilia should take steps to avoid injuries, accidents, and excessive strain on the joints. This can help to prevent episodes of bleeding. For example: 

• An infant with hemophilia should have appropriate padding in his crib or playpen.
• A toddler with hemophilia should be supervised as he learns to walk.
• A school-age child with hemophilia should avoid contact sports and activities that have a high risk of trauma.

People with hemophilia may need blood transfusions during or after an episode of bleeding. They should be immunized against hepatitis A and B, diseases that can be carried in blood products. 

People with hemophilia should avoid aspirin and other medications that affect blood clotting. 

Treating hemophilia

Preventive treatment

Clotting factor concentrates help to replace the missing clotting factor in the blood. This can help to decrease how often and how severely you bleed. Clotting factor concentrates are given by injection into a vein, and may be recommended to prevent bleeding (either regularly or prior to high-risk events such as planned surgery).

Some hemophilia factors are genetically engineered while others are prepared from carefully screened blood donors.

Because these clotting factors are large proteins (large complex chemical structures), patients may develop inhibitors or antibodies that neutralize the ability of these factors to be effective. Additional medicines may be required if an inhibitor develops after getting these clotting factors.

In addition to therapies that replace deficient clotting factors, a number of newer treatments are available for prevention of bleeding in Hemophilia A and/or B, including:

• emicizumab (Hemlibra), an antibody that mimics the function of Factor VIII
• valoctocogene roxaparvovec (Roctavian), a gene therapy that instructs cells to produce Factor VIII
• etranacogene dezaparvovec (Hemgenix), a gene therapy that promotes production of functioning Factor IX
• fitusiran (Qfitlia), a medicine that improves clotting by blocking a protein (called anti-thrombin) that normally inhibits clotting
• marstacimab (Hympavzi) and Concizumab (Alhemo), antibodies that improve clotting by inhibiting a part of the coagulation system (called the tissue factor pathway).

Treatment for excessive bleeding

Sometimes excessive bleeding occurs despite preventive treatments and the use of replacement clotting factors. Hospital treatment is necessary when bleeding occurs. The situation is an emergency when it involves the brain, neck, the central nervous system, or a vital organ.

People with hemophilia may require blood transfusions to treat excessive blood loss.

All surgical or invasive procedures should be done in a hospital to properly handle bleeding. Consult your doctor before having dental work.

When to call a professional

Call your doctor if you notice unexplained or severe bruises or a warm, painful joint on your child's body. If you are an adult and you experience these symptoms, call your doctor.

A physician trained in disorders of the blood (a hematologist) is best equipped to diagnose and treat hemophilia. People with bleeding disorders should consult with these specialists.

People with hemophilia should wear a medical alert bracelet at all times indicating their condition.

Prognosis

How well you do depends on the type of hemophilia and its severity. Thanks to the development of clotting factor products and other medications that can reduce the risk of excessive bleeding, most people with hemophilia can look forward to a near-normal life span.

There are three main complications that may develop in people with hemophilia:

• Joint damage: Over time, repeated episodes of bleeding into joints can result in severe joint disease.
• Blood-borne infection: Blood testing and purification techniques have improved markedly over the years. It is now exceedingly rare for hepatitis or HIV infections to be transmitted through blood products.
• Development of inhibitor antibodies: People who are treated with clotting factors can develop inhibitor antibodies. These are proteins that decrease the effectiveness of the clotting treatment.

Additional info

National Heart, Lung, and Blood Institute (NHLBI)
https://www.nhlbi.nih.gov/

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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