Definition and Overview

Blood clotting is the body’s way to prevent excessive bleeding. When a person is injured or wounded, the body sends platelets to the injured site where they form a plug. The blood’s clotting factors then form a fibrin clot to hold the platelets in place. This keeps more blood from flowing out. It also promotes healing.

People with haemophilia lack certain clotting factors. Because their blood does not clot the way it should, they can lose a lot of blood from even minor cuts and injuries. They are also at risk of internal bleeding, which can damage their organs, joints, and tissues.

The disorder is rare and normally runs in the family (inherited). It can affect both men and women. However, the symptoms are more severe in men. In the United States, the disorder affects one in every 5,000 male births. It can be mild, moderate, or severe. But with proper treatment, patients have a chance at living a normal life.

There are two main types of the disorder, namely haemophilia A and haemophilia B. Both produce the same signs and symptoms. However, they are caused by different gene mutations and involve different clotting factors. The former occurs when a person has a defective or missing factor VIII. The latter, on the other hand, is caused by a missing or defective factor IX. Both types can be passed down from parents to children. However, up to 33% of cases occur due to spontaneous mutations.

A related condition is called Von Willebrand disease (VWD). It is another genetic blood clotting disorder. It occurs due to a defective or missing clotting protein that binds factor VIII and platelets in blood vessel walls. VWD is the most common bleeding disorder. It affects up to 1% of people in the United States.

Causes of Condition

The disorder is caused by a genetic mutation. It is commonly passed on by mothers to their sons. Most women with the condition do not have symptoms, and are often considered as carriers. A child gets one chromosome from each parent. A female inherits two X chromosomes, one from each parent. A male, on the other hand, inherits his X chromosome from his mother and his Y chromosome from his father. The gene that causes blood clotting defects is on the X chromosome. For this reason, fathers cannot pass the disorder on to their children.

Key Symptoms

The first warning sign of the condition is abnormal bleeding. This can be mild, moderate, or severe. The severity depends on how much blood clotting factors are missing from the blood. In mild cases, excessive bleeding only occurs when a person is wounded or injured. In severe cases, on the other hand, they experience spontaneous bleeding. A small cut can cause them to lose a large amount of blood.

Patients can show symptoms within the first two years of life. These include:

  • Easy bruising - Unusual bruising starts to show when a child begins to stand or crawl.

  • Unusual bleeding after drawing blood for newborn screening tests.

  • Bleeding from the mouth and frequent nosebleeds.

  • Excessive bleeding when new teeth are erupting.

  • Excessive bleeding after dental work.

  • Blood in the urine - This signals bleeding from the urinary tract.

  • Blood in the stool - This signals bleeding from the gastrointestinal (GI) tract.

  • Unexplained nausea, vomiting, and lethargy - These symptoms signal bleeding into the skull or brain.

  • Joint pain - Occurs due to bleeding into the joints.

Who to See and Types of Treatments Available

Severe cases are caught very early in life. Most patients are diagnosed before they turn a year old. This is because the disorder causes symptoms that are hard to ignore. These include excessive bleeding when new teeth are growing or following routine vaccinations. These prompt parents to take their children to their doctor. Mild cases, on the other hand, are often caught only after a serious injury or during surgery.

The disorder is diagnosed with screening and clotting factor tests. These tests are used to:

  • Measure how long it takes for blood to clot.

  • Measure the function of various clotting factors. This determines the type of haemophilia the patient has and its severity.

  • Assess the body’s ability to form a blood clot.

There is no cure for the condition. However, there are treatments that can control its symptoms and severity. In mild cases, injectable hormones are used to help the body make blood clots. But the standard treatment is replacement therapy in which concentrates of clotting factors are dripped into a vein. The therapy can be performed on an as-needed basis or only when a person is bleeding. The therapy can also be preventive in nature. In such cases, the patient undergoes transfusions on a regular basis even when there are no injuries.

The therapy can be done at home. Patients are taught by health care providers on how to do infusions on their own either for themselves or their children. Having easy access to treatment helps prevent massive blood loss. It is also less expensive than receiving treatment in the hospital or doctor’s office.


  • Living with hemophilia. National Heart, Lung, and Blood Institute.

  • Centers for Disease Control. Hemophilia.

  • Konkle BA, Josephson NC, Fletcher SMN, Thompson AR. Hemophilia A. GeneReviews. September 2011;

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