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Haemophilia is a rare condition that affects the blood's ability to clot. It's usually inherited, and most people who have it are male.
Normally, when you cut yourself, substances in the blood known as clotting factors combine with blood cells called platelets to make the blood sticky. This makes the bleeding stop eventually.
People with haemophilia don't have as many clotting factors as there should be in the blood. This means they bleed for longer than usual.
The symptoms of haemophilia can be mild to severe, depending on the level of clotting factors you have.
The main symptom is bleeding that doesn't stop, also called prolonged bleeding.
People with haemophilia may have:
Read more about the symptoms of haemophilia.
See your doctor if:
Find out more about how haemophilia is inherited .
There's a small risk people with haemophilia may have a bleed inside their skull.
Symptoms of this include:
Call for an ambulance if you think someone's bleeding inside the skull.
Blood tests can diagnose haemophilia and find out how severe it is.
If there's no family history of haemophilia, it's usually diagnosed when a child begins to walk or crawl.
Mild haemophilia may only be discovered later, usually after an injury or a dental or surgical procedure.
If you have a family history of haemophilia and you're planning to get pregnant, genetic testing and counselling can help determine the risk of passing the condition on to a child.
This may involve testing a sample of your tissue or blood to look for signs of the genetic mutation that causes haemophilia.
Tests during pregnancy can diagnose haemophilia in the baby. These include:
There's a small risk of these procedures causing problems such as miscarriage](/condition/miscarriage) or [premature labour , so you may want to discuss this with your doctor.
If haemophilia is suspected after your child's born, a blood test can usually confirm the diagnosis. Blood from the umbilical cord can be tested at birth if there's a family history of haemophilia.
Read more about how a blood test is performed .
There's no cure for haemophilia, but treatment usually allows a person with the condition to enjoy a good quality of life.
Genetically engineered clotting factor medicines are used to prevent and treat prolonged bleeding. These medicines are given as an injection.
In milder cases, injections are usually only given in response to prolonged bleeding. More severe cases are treated with regular injections to prevent bleeding.
Read more about treatments for haemophilia.
With treatment, most people with haemophilia can live a normal life.
However, you should:
Looking after your teeth and gums helps avoid problems such as gum disease , which can cause bleeding. Most non-surgical dental treatment can be carried out at a general dental practice.
Your care team at the hospital can offer advice about surgical dental procedures, such as having a tooth removed, and further information and advice about living with haemophilia.
The symptoms of haemophilia depend on how severe the condition is, but the main sign is prolonged bleeding.
The bleeding may occur spontaneously. For example, this could be:
The bleeding may also occur after a medical procedure, such as having a tooth removed.
The severity of haemophilia is determined by the level of clotting factors in a person's blood:
Find out when to seek emergency medical help.
Children born with mild haemophilia may not have any symptoms for many years.
The condition usually only becomes apparent after a significant wound or surgery, or a dental procedure such as having a tooth removed. These events could cause unusually prolonged bleeding.
Children with moderate haemophilia are affected in the same way as those with mild haemophilia, but also bruise easily.
They may also have symptoms of internal bleeding around their joints, particularly if they have a knock or a fall that affects their joints. This is known as a joint bleed.
The symptoms usually begin with a tingling feeling of irritation and mild pain in the affected joint – most commonly the ankles, knees, and elbows. Less commonly, the shoulder, wrist, and hip joints can also be affected.
If a joint bleed isn't treated, it can lead to:
The symptoms of severe haemophilia are similar to those of moderate haemophilia. However, joint bleeding is more frequent and severe.
Children with severe haemophilia have spontaneous bleeding. This means they start bleeding for no apparent reason.
For example, this could be:
Without treatment, people with severe haemophilia can develop:
There's a small risk of bleeding inside the skull, known as an intracranial haemorrhage. It's estimated 3% of people with moderate or severe haemophilia will have an intracranial haemorrhage.
However, spontaneous bleeding inside the skull is uncommon and usually only caused by a head injury .
Bleeding in the skull should be treated as a medical emergency.
The symptoms of an intracranial haemorrhage include:
Call for an ambulance if you think someone is bleeding inside the skull.
Haemophilia is caused by an inherited genetic mutation, which mainly affects males.
A genetic mutation is a permanent alteration in the DNA sequence that makes up a gene. This means that some of the body's processes won't work in the normal way.
The type of mutation determines whether a person will experience mild, moderate or severe symptoms.
The gene mutation is found on the X chromosome. It can be carried by either the mother or father, or both.
You can read more about chromosomes and how we inherit mutations by reading about genetics .
The chances of a child inheriting the haemophilia mutation depend on which of their parents has the mutated gene.
If a woman with the mutated chromosome and an unaffected man have a baby, there's a:
In the last situation, the girl becomes a carrier of the mutated gene. This means she can pass it on to her children, but won't usually have any severe symptoms of haemophilia herself.
However, some female carriers sometimes have bleeding problems, such as heavy periods .
If a man with haemophilia has a son with an unaffected woman, there's no chance the boy will get haemophilia.
This is because he always inherits his X chromosome from his mother, who in this case doesn't have the mutated gene.
However, any daughters the man has will become carriers of the mutated haemophilia gene and may pass it on to their children.
If a woman with the mutated chromosome and a man with haemophilia have a baby, there's a:
This means it's possible for a female to have haemophilia, although it's very rare.
In some cases, a boy is born with haemophilia even though there's no family history of the condition.
In such cases, it's thought the mutation developed spontaneously in the boy's mother, grandmother or great-grandmother, but until then a male member of the family had never inherited the mutated gene.
Some studies have shown there's no known family history of haemophilia in up to a third of new cases.
Blood cells called platelets are very important for blood clotting. These cells have a sticky surface that allows them to clump together to stop the flow of blood.
Platelets also need clotting factors. These are proteins that form a "web" around the platelets, helping them to stay in place.
The mutated haemophilia gene means a child with the condition doesn't have enough clotting factors in their blood.
Several different clotting factors are present in the blood. They are numbered using roman numerals.
For example, in haemophilia A there's not enough clotting factor VIII (8) in the blood. In haemophilia B, there's not enough clotting factor IX (9) in the blood.
The recommended treatment plan for haemophilia depends on how severe the condition is.
There are two main approaches to treatment:
Haemophilia is usually treated by a team at a specialist haemophilia hospital department.
Most cases of haemophilia are severe and need preventative treatment (prophylaxis). This involves regular injections of clotting factor medicine.
If your child has haemophilia, you'll be trained to give them the injections when they're young.
They'll be taught how to inject themselves when they're older to help avoid regular hospital appointments.
In some cases, injections may be given into a device called an implantable port, which can be surgically placed under the skin.
This port is connected to a blood vessel near the heart, so you don't need to try to find a vein for every injection.
People having preventative treatment need regular follow-up appointments with their care team so their progress can be monitored.
Preventative treatment is usually continued for life. It may be possible for someone to change to on-demand treatment, but they may be advised to switch back to preventative treatment if they have any episodes of significant bleeding.
There are different types of haemophilia. This page covers the most common types: haemophilia A and haemophilia B. They have similar symptoms, but need different treatments because different clotting factors are affected.
Preventative treatment for haemophilia A involves regular injections of a medicine called octocog alfa.
This is an engineered version of clotting factor VIII (8), the clotting factor people with haemophilia A don't have enough of. Injections every 48 hours are often recommended.
Side effects of octocog alfa are uncommon, but can include an itchy skin rash, and redness and soreness at the site of the injection.
Preventative treatment for people with haemophilia B involves regular injections of a medicine called nonacog alfa.
This is an engineered version of clotting factor IX (9), which people with haemophilia B don't have enough of. Injections twice a week are often recommended.
Side effects of nonacog alfa are uncommon, but include headaches, altered taste, nausea, and discomfort and swelling at the injection site.
In mild or moderate cases, treatment for haemophilia may only be necessary as an immediate response to bleeding.
People with haemophilia A can be treated on-demand with injections of octocog alfa or a medication called desmopressin.
Desmopressin is a synthetic hormone. Hormones are powerful chemicals that can have a wide range of effects on the body.
Desmopressin works by stimulating the production of clotting factor VIII (8) and is usually given by injection.
Possible side effects of desmopressin include headache, stomach pain, and nausea.
On-demand treatment for haemophilia B usually involves injections of nonacog alfa.
Complications can include developing inhibitors in your immune system, and joint problems.
Some people who take blood clotting factor medicine develop antibodies in their immune system, called inhibitors, that make the medicine less effective.
People having treatment for haemophilia should be regularly tested for inhibitors.
Inhibitors can be treated with immune tolerance induction (ITI). This involves daily injections of clotting factors so the immune system should begin to recognise them and stop producing inhibitors.
ITI is usually offered to people with severe haemophilia A. People with haemophilia B may be offered ITI, but it's less effective and carries a risk of anaphylaxis for them.
People with mild or moderate haemophilia A who develop inhibitors may be offered either bypass therapy or immunosuppressants.
Bypass therapy uses a medicine called bypass agent to stop bleeding when it happens.
Immunosuppressants are medicines that suppress your immune system.
Joint bleeds can damage the soft spongy tissue in your joints called cartilage, and the thin layer of tissue lining the inside of the joint (synovium). The more damaged a joint is, the more vulnerable it is to bleeding.
Joint damage is more common in older adults with severe haemophilia. It's hoped modern treatments mean children growing up with haemophilia today won't have joint damage.
Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.