Hemophilia (heem-o-FILL-ee-ah) is a rare bleeding disorder in which the blood doesn't clot normally.
If you have hemophilia, you may bleed for a longer time than others after an injury. You also may bleed inside your body (internally), especially in your knees, ankles, and elbows. This bleeding can damage your organs and tissues and may be life threatening.
Hemophilia usually is inherited. "Inherited” means that the disorder is passed from parents to children through genes.
People born with hemophilia have little or no clotting factor. Clotting factor is a protein needed for normal blood clotting. There are several types of clotting factors. These proteins work with platelets (PLATE-lets) to help the blood clot.
Platelets are small blood cell fragments that form in the bone marrow—a sponge-like tissue in the bones. Platelets play a major role in blood clotting. When blood vessels are injured, clotting factors help platelets stick together to plug cuts and breaks on the vessels and stop bleeding.
The two main types of hemophilia are A and B. If you have hemophilia A, you're missing or have low levels of clotting factor VIII (8). About 8 out of 10 people who have hemophilia have type A. If you have hemophilia B, you're missing or have low levels of clotting factor IX (9).
Rarely, hemophilia can be acquired. "Acquired” means you aren't born with the disorder, but you develop it during your lifetime. This can happen if your body forms antibodies (proteins) that attack the clotting factors in your bloodstream. The antibodies can prevent the clotting factors from working.
This article focuses on inherited hemophilia.
Hemophilia can be mild, moderate, or severe, depending on how much clotting factor is in your blood. About 7 out of 10 people who have hemophilia A have the severe form of the disorder.
People who don't have hemophilia have a factor VIII activity of 100 percent. People who have severe hemophilia A have a factor VIII activity of less than
Hemophilia usually occurs in males (with rare exceptions). About 1 in 5,000 males are born with hemophilia each year.
If you have inherited hemophilia, you're born with the disorder. It's caused by a defect in one of the genes that determine how the body makes blood clotting factor VIII or IX. These genes are located on the X chromosomes (KRO-muh-somz).
Chromosomes come in pairs. Females have two X chromosomes, while males have one X and one Y chromosome. Only the X chromosome carries the genes related to clotting factors.
A male who has a faulty hemophilia gene on his X chromosome will have hemophilia. A female must have the faulty gene on both of her X chromosomes to have hemophilia, which is very rare.
If a female has the faulty gene on only one of her X chromosomes, she is a "hemophilia carrier.” Carriers don't have hemophilia, but they can pass the faulty gene to their children.
Below are two examples of how the hemophilia gene is inherited.
Females who are hemophilia carriers usually have enough clotting factors from their one normal X chromosome to prevent serious bleeding problems. However, up to
Very rarely, a girl is born with hemophilia. This can happen if her father has hemophilia and her mother is a carrier.
Some males who have the disorder are born to mothers who aren't carriers. In these cases, a mutation (random change) occurs in the gene as it is passed to the child.
The major signs and symptoms of hemophilia are excessive bleeding and easy bruising.
The extent of bleeding depends on how severe the hemophilia is.
Children who have mild hemophilia may not have signs unless they have excessive bleeding from a dental procedure, an accident, or surgery. Males who have severe hemophilia may bleed heavily after circumcision.
Bleeding can occur on the body's surface (external bleeding) or inside the body (internal bleeding).
Signs of external bleeding may include:
Signs of internal bleeding may include:
Bleeding in the knees, elbows, or other joints is another common form of internal bleeding in people who have hemophilia. This bleeding can occur without obvious injury.
At first, the bleeding causes tightness in the joint with no real pain or any visible signs of bleeding. The joint then becomes swollen, hot to touch, and painful to bend.
Swelling continues as bleeding continues. Eventually, movement in the joint is temporarily lost. Pain can be severe. Joint bleeding that isn't treated quickly can damage the joint.
Internal bleeding in the brain is a very serious complication of hemophilia. It can happen after a simple bump on the head or a more serious injury. The signs and symptoms of bleeding in the brain include:
If you or your child appears to have a bleeding problem, your doctor will ask about your personal and family medical histories. This will reveal whether you or your family members, including women and girls, have bleeding problems. However, some people who have hemophilia have no recent family history of the disease.
You or your child also will likely have a physical exam and blood tests to diagnose hemophilia. Blood tests are used to find out:
The test results will show whether you have hemophilia, what type of hemophilia you have, and how severe it is.
Hemophilia A and B are classified as mild, moderate, or severe, depending on the amount of clotting factor VIII or IX in the blood.
|Mild hemophilia||5–40 percent of normal clotting factor|
|Moderate hemophilia||1–5 percent of normal clotting factor|
|Severe hemophilia||Less than 1 percent of normal clotting factor|
The severity of symptoms can overlap between the categories. For example, some people who have mild hemophilia may have bleeding problems almost as often or as severe as some people who have moderate hemophilia.
Severe hemophilia can cause serious bleeding problems in babies. Thus, children who have severe hemophilia usually are diagnosed during the first year of life. People who have milder forms of hemophilia may not be diagnosed until they're adults.
The bleeding problems of hemophilia A and hemophilia B are the same. Only special blood tests can tell which type of the disorder you or your child has. Knowing which type is important because the treatments are different.
Pregnant women who are known hemophilia carriers can have the disorder diagnosed in their unborn babies as early as 12 weeks into their pregnancies.
Women who are hemophilia carriers also can have "preimplantation diagnosis" to have children who don't have hemophilia.
For this process, women have their eggs removed and fertilized by sperm in a laboratory. The embryos are then tested for hemophilia. Only embryos without the disorder are implanted in the womb.
The main treatment for hemophilia is called replacement therapy. Concentrates of clotting factor VIII (for hemophilia A) or clotting factor IX (for hemophilia B) are slowly dripped or injected into a vein. These infusions help replace the clotting factor that's missing or low.
Clotting factor concentrates can be made from human blood. The blood is treated to prevent the spread of diseases, such as hepatitis. With the current methods of screening and treating donated blood, the risk of getting an infectious disease from human clotting factors is very small.
To further reduce the risk, you or your child can take clotting factor concentrates that aren't made from human blood. These are called recombinant clotting factors. Clotting factors are easy to store, mix, and use at home—it only takes about
You may have replacement therapy on a regular basis to prevent bleeding. This is called preventive or prophylactic (PRO-fih-lac-tik) therapy. Or, you may only need replacement therapy to stop bleeding when it occurs. This use of the treatment, on an as-needed basis, is called demand therapy.
Demand therapy is less intensive and expensive than preventive therapy. However, there's a risk that bleeding will cause damage before you receive the demand therapy.
Complications of replacement therapy include:
Antibodies to the clotting factor. Antibodies can destroy the clotting factor before it has a chance to work. This is a very serious problem. It prevents the main treatment for hemophilia (replacement therapy) from working.
These antibodies, also called inhibitors, develop in about 20–30 percent of people who have severe hemophilia A. Inhibitors develop in 2–5 percent of people who have hemophilia B.
When antibodies develop, doctors may use larger doses of clotting factor or try different clotting factor sources. Sometimes the antibodies go away.
Researchers are studying new ways to deal with antibodies to clotting factors.
Viruses from human clotting factors. Clotting factors made from human blood can carry the viruses that cause HIV/AIDS and hepatitis. However, the risk of getting an infectious disease from human clotting factors is very small due to:
Damage to joints, muscles, and other parts of the body. Delays in treatment can cause damage such as:
You can do both preventive (ongoing) and demand (as-needed) replacement therapy at home. Many people learn to do the infusions at home for their child or for themselves. Home treatment has several advantages:
Discuss options for home treatment with your doctor or your child's doctor. A doctor or other health care provider can teach you the steps and safety procedures for home treatment. Hemophilia treatment centers are another good resource for learning about home treatment (discussed in "Living With Hemophilia”).
Doctors can surgically implant vein access devices to make it easier for you to access a vein for treatment with replacement therapy. These devices can be helpful if treatment occurs often. However, infections can be a problem with these devices. Your doctor can help you decide whether this type of device is right for you or your child.
Desmopressin (DDAVP) is a man-made hormone used to treat people who have mild hemophilia A. DDAVP isn't used to treat hemophilia B or severe hemophilia A.
DDAVP stimulates the release of stored factor VIII and von Willebrand factor; it also increases the level of these proteins in your blood. Von Willebrand factor carries and binds factor VIII, which can then stay in the bloodstream longer.
DDAVP usually is given by injection or as nasal spray. Because the effect of this medicine wears off if it's used often, the medicine is given only in certain situations. For example, you may take this medicine prior to dental work or before playing certain sports to prevent or reduce bleeding.
Antifibrinolytic medicines (including tranexamic acid and epsilon aminocaproic acid) may be used with replacement therapy. They're usually given as a pill, and they help keep blood clots from breaking down.
These medicines most often are used before dental work or to treat bleeding from the mouth or nose or mild intestinal bleeding.
Researchers are trying to find ways to correct the faulty genes that cause hemophilia. Gene therapy hasn't yet developed to the point that it's an accepted treatment for hemophilia. However, researchers continue to test gene therapy in clinical trials.
For more information, go to the "Clinical Trials" section of this article.
Pain medicines, steroids, and physical therapy may be used to reduce pain and swelling in an affected joint. Talk with your doctor or pharmacist about which medicines are safe for you to take.
The type of treatment you or your child receives depends on several things, including how severe the hemophilia is, the activities you'll be doing, and the dental or medical procedures you'll be having.
For both types of hemophilia, getting quick treatment for bleeding is important. Quick treatment can limit damage to your body. If you or your child has hemophilia, learn to recognize signs of bleeding.
Other family members also should learn to watch for signs of bleeding in a child who has hemophilia. Children sometimes ignore signs of bleeding because they want to avoid the discomfort of treatment.
If you or your child has hemophilia, you can take steps to prevent bleeding problems. Thanks to improvements in treatment, a child who has hemophilia today is likely to live a normal lifespan.
The Federal Government funds a nationwide network of hemophilia treatment centers (HTCs). These centers are an important resource for people who have hemophilia and their families.
The medical experts at HTCs provide treatment, education, and support. They can teach you or your family members how to do home treatments. Center staff also can provide your doctor with information.
People who get care at HTCs are less likely than those who get care elsewhere to have bleeding complications and hospitalizations. They're also more likely to have a better quality of life. This may be due to the centers' emphasis on bleeding prevention and the education and support provided to patients and their caregivers.
More than 100 federally funded HTCs are located throughout the United States. Many HTCs are located at major university medical and research centers. The hemophilia teams at these centers include:
To find an HTC located near you, go to the directory of HTCs on the Centers for Disease Control and Prevention's Web site. Many people who have hemophilia go to HTCs for annual checkups, even if it means traveling some distance to do so.
At an HTC, you or your child may be able to take part in clinical research and benefit from the latest hemophilia research findings. The HTC team also will work with your local health care providers to help meet your needs or your child's needs.
If you have hemophilia, you can take steps to avoid complications. For example:
It's a good idea to keep a record of all previous treatments. Be sure to take this information with you to medical appointments and to the hospital or emergency room.
You may have emotional, financial, social, or other strains as you adjust to having a child who has hemophilia. Learn all you can about the disorder and get the support you need.
Talk with doctors and other health care providers about treatment, prevention of bleeding, and what to do during an emergency.
The care teams at HTCs can provide your child with treatment and help educate and support you. The social worker on the team can help with emotional issues, financial and transportation problems, and other concerns.
Seek the many resources available through the Web, books, and other materials, including those provided by national and local hemophilia organizations.
Look into support groups that offer a variety of activities for children who have hemophilia and for family members. Some groups offer summer camps for children who have hemophilia. Ask your doctor, nurse coordinator, or social worker about these groups and camps.
Challenges will occur as your child grows and becomes more active. In addition to treatment and regular health and dental care, your child needs information about hemophilia that he or she can understand.
Children who have hemophilia also need ongoing support, and they need to be reassured that the condition isn't their fault.
Young children who have hemophilia need extra protection from things in the home and elsewhere that could cause injuries and bleeding:
You also should learn how to examine your child for and recognize signs of bleeding. Learn to prepare for bleeding episodes when they occur. Keep a cold pack in the freezer ready to use as directed or to take along with you to treat bumps and bruises.
Popsicles work fine when there is minor bleeding in the mouth. You also might want to keep a bag ready to go with items you'll need if you must take your child to the emergency room or elsewhere.
Be sure that anyone who is responsible for your child knows that he or she has hemophilia. Talk with your child's babysitters, daycare providers, teachers, other school staff, and coaches or leaders of afterschool activities about when to contact you or to call 9–1–1 for emergency care.
Your child should wear a medical ID bracelet or necklace. If your child is injured, the ID will alert anyone caring for your child about his or her hemophilia.
Physical activity helps keep muscles flexible, strengthens joints, and helps maintain a healthy weight. Children and adults who have hemophilia should be physically active, but they may have limits on what they can do safely.
People who have mild hemophilia can take part in many activities. Those who have severe hemophilia should avoid contact sports and other activities that are likely to lead to injuries that could cause bleeding. Examples of these activities include football, hockey, and wrestling.
Physical therapists at HTCs can develop exercise programs tailored to your needs and teach you how to exercise safely.
Talk with your doctor or physical therapist about recommended types of physical activity and sports. In general, some safe physical activities are swimming, biking (wearing a helmet), walking, and golf.
To prevent bleeding, you also may be able to take clotting factors prior to exercise or a sporting event.
Some medicines increase the risk of bleeding, such as:
Talk with your doctor or pharmacist about which medicines are safe for you to take.
Home treatment with replacement therapy has many benefits. It lets you treat bleeding early, before complications are likely to develop. Home treatment also can prevent frequent trips to the doctor's office or hospital. This can give you more independence and control over your hemophilia.
However, if you're treating yourself or your child with clotting factors at home, you should take some steps for safety:
When you're traveling, be sure to take enough treatment supplies along. You also should carry a letter from your doctor describing your hemophilia and treatment. It's a good idea to find out in advance where to go for care when out of town.
Clotting factors are very costly. Many health insurance companies will only pay for clotting factors on a case-by-case basis. It's important to know:
As children grow, it's important to learn about available options for insurance. Look into what kinds of health insurance are offered when seeking a job.
The National Heart, Lung, and Blood Institute (NHLBI) is strongly committed to supporting research aimed at preventing and treating heart, lung, and blood diseases and conditions and sleep disorders.
NHLBI-supported research has led to an improved understanding of hemophilia and advances in treating the disorder. The NHLBI continues to support research aimed at learning more about hemophilia. For example, studies are under way to explore how to make hemophilia treatments more effective.
Research often depends on the willingness of volunteers to take part in clinical trials. Clinical trials test new ways to prevent, diagnose, or treat various diseases and conditions.
For example, new treatments for a disease or condition (such as medicines, medical devices, surgeries, or procedures) are tested in volunteers who have the illness. Testing shows whether a treatment is safe and effective in humans before it is made available for widespread use.
By taking part in a clinical trial, you can gain access to new treatments before they're widely available. You also will have the support of a team of health care providers, who will likely monitor your health closely. Even if you don't directly benefit from the results of a clinical trial, the information gathered can help others and add to scientific knowledge.
If you volunteer for a clinical trial, the research will be explained to you in detail. You'll learn about treatments and tests you may receive, and the benefits and risks they may pose. You'll also be given a chance to ask questions about the research. This process is called informed consent.
If you agree to take part in the trial, you'll be asked to sign an informed consent form. This form is not a contract. You have the right to withdraw from a study at any time, for any reason. Also, you have the right to learn about new risks or findings that emerge during the trial.
For more information about clinical trials related to hemophilia, talk with your doctor. You also can visit the following Web sites to learn more about clinical research and to search for clinical trials:
For more information about clinical trials for children, visit the NHLBI's Children and Clinical Studies Web page.
The NHLBI updates Health Topics articles on a biennial cycle based on a thorough review of research findings and new literature. The articles also are updated as needed if important new research is published. The date on each Health Topics article reflects when the content was originally posted or last revised.