What Is Haemophilia A?

  • Nell MarquessBachelor of Medicine, Bachelor of Surgery - MBBS, Medicine, University of Exeter, UK
  • Ellen RogersMSc in Advanced Biological Sciences, University of Exeter, UK


Haemophilia A is a rare genetic disorder that affects the blood.1 People with haemophilia A bleed more easily than the average person. This can put them at risk of complications such as internal bleeding and shock if they do not receive adequate treatment and take necessary precautions.2

About haemophilia 

Two types of haemophilia exist: haemophilia A and haemophilia B. Haemophilia occurs when the body is unable to make certain proteins, known as clotting factors.3 In a healthy person, clotting factors bind to substances in the bloodstream to form clots. Clots will form at sites of injury and prevent further bleeding. The absence of certain clotting factors in haemophilia patients means that they struggle to form clots and, therefore, will bleed for longer if they are hurt. It also means that they are more likely to bleed when a normal person might not.

Patients who suffer from haemophilia A have a lack of clotting factor VIII (8) specifically, whereas patients with haemophilia B have a lack of clotting factor IX (9).3 The severity of haemophilia varies depending on the amount of clotting factor a patient makes compared to the normal level. The less clotting factor VIII a haemophilia A patient has, the more likely they are to have frequent, severe bleeds. For this reason, although some patients with severe symptoms are diagnosed in their early childhood, others are not diagnosed until adulthood. Patients with different severities of haemophilia will have different management plans to best suit them. 

Symptoms of haemophilia A

Symptoms that may be experienced by individuals with haemophilia include:1,3

  • Easy bruising
  • Bleeding from the gums
  • Long lasting nosebleeds
  • Excessive bleeding and swelling at sites of injury
  • Heavy menstrual periods for those assigned female at birth (AFAB)
  • Joint pain

Haemophilia can also cause more severe complications. Excessive bleeding is dangerous as our blood is crucial for transporting oxygen around our bodies to our organs. If our blood volume drops too low, our organs may not receive adequate oxygen, which can, in turn, lead to the death of cells that make up our organs. This phenomenon is known as hypovolemic shock and is an emergency.2

Patients with haemophilia A should also be aware of internal bleeding.4 As patients will not be able to see that they are bleeding, internal bleeding is more likely to be life-threatening. Internal bleeding is especially dangerous in the skull due to the pressure it puts on the brain. Bleeding on the brain is a medical emergency and requires urgent attention. Signs of a brain bleed include headaches, nausea and vomiting, confusion, dizziness, collapse and seizures.4

Another complication of haemophilia is chronic pain, specifically in the joints. The joint most commonly affected in haemophilia patients is the knee.5 Patients with weak joints are more susceptible to bleeding due to friction and age-related wear and tear to the bones and joint capsule.2 This can worsen as patients age and lead to arthritis.

Genetics and haemophilia A

The inheritance pattern of haemophilia A means that it is significantly more common in men than women.3 Haemophilia A is caused by mutations in the gene encoding clotting factor VIII. This gene is located on the X chromosome. Men have one X chromosome, whereas women have two. For a man to develop haemophilia A, they would only have to inherit one copy of the faulty gene passed down from their mother. However, a woman would need two copies of the faulty gene to have symptoms; one passed down from each parent. Women, therefore, can be unaffected and exist as ‘carriers’ of one faulty haemophilia gene. Despite this, if a female carrier has a son, the son has a 50% chance of being affected.

Roughly one in 5000 men are born with haemophilia A.6,8

Diagnosis and testing

When a doctor suspects haemophilia, they may ask about risk factors (such as family history) as well as your symptoms. It is useful for them to know a history of any bleeding episodes, for example, frequent nosebleeds in childhood. Haemophilia A is diagnosed using blood tests to check how good the blood is at forming clots, as well as checking the concentration of clotting factor VIII.At this point, other common bleeding disorders - such as haemophilia B and von Willebrand disease - will be ruled out.

Further to this, genetic testing will confirm a diagnosis of haemophilia A. Genetic testing is also available for female relations of known haemophilia patients and as part of prenatal care for pregnant women who are haemophilia carriers.2

Managing haemophilia A

Haemophilia A is managed by a team of healthcare professionals, with haematologists, nurses and physiotherapists providing the majority of care. The two key aspects of management are the prevention of bleeding episodes and the management of acute bleeds.1,3

To prevent bleeding episodes, scheduled infusions of plasma-derived clotting factor VIII can be given, tailored to each patient’s disease severity.7 These may be administered in a hospital or in the community. For patients with mild haemophilia A, it may be decided that long-term prophylaxis is not necessary, only treatment for any acute bleeds.

The treatment of acute bleeds depends on their severity. All patients and their family members should be offered first-aid training on managing acute bleeds. It is crucial that patients learn how to assess bleed severity and determine whether they need to seek help. Whilst patients may be able to manage minor bleeds, such as nosebleeds at home, any trauma-related bleeds should be reviewed by a healthcare professional in the hospital.7

Patients may be admitted to the hospital for further care, especially if the bleeding is severe. Patients who are bleeding into a joint are likely to be reviewed by an orthopaedic team, as well as physiotherapists, before discharge.3,5 Upon discharge, this will aid their recovery and help prevent further bleeding.  

Aside from this, a comprehensive care plan for patients with haemophilia A should include pain management, psychological support, and advice on nutrition, physical activity and injury prevention.5

Many haemophilia A patients suffer from chronic pain due to bleeding into joints and muscles. Research suggests that physical therapies (for example, hydrotherapy and resistance training) and psychological therapies may be good supplements for pain management alongside medication initiated by a healthcare professional.6

Psychological support is available to help individuals with haemophilia A and their families cope with their new diagnosis. Patients are encouraged to access talking therapies through their GP if they feel that they would benefit from them. Further, The Haemophilia Society UK has a wide range of support available on their website, including specific support for those who have recently been diagnosed.8

A balanced diet is really important in aiding joint health in haemophilia patients.5 Eating calcium-rich foods, and plenty of protein can contribute to muscle and joint strength, ultimately preventing the likelihood of joint bleeds.9 Adequate hydration is also crucial, as dehydration makes the blood thicker - further delaying the formation of clots and complete wound healing. On top of this, strength and resistance training can be useful in strengthening the joints and preventing joint bleeds.5 Despite this, the importance of protective gear and staying safe from injury whilst exercising is equally important. 

Complications and long-term outlook

Potential long-term complications of haemophilia A include:1,2

  • Chronic pain
  • Joint damage and arthritis
  • Sequelae of brain bleeds, including seizures and strokes

Additionally, some haemophilia patients may develop a protein called an ‘inhibitor’ that prevents clotting factor VIII infusions from working properly.5 Because of this, these patients are harder to treat and may be at higher risk of complications. Further research is being done into new treatments for haemophilia patients with inhibitors.

Support and resources

As there is no cure for haemophilia A, it is important that patients are supported and empowered throughout treatment and health.

Patients may benefit from being put in touch with support groups such as The Haemophilia Society UK, especially around the time of diagnosis.8 Additionally, not-for-profits such as the World Federation for Hemophilia have websites with detailed information, support and news on up-to-date research for improving haemophilia A management.

If you or a loved one is struggling with their haemophilia diagnosis, don’t hesitate to reach out and contact your GP to talk about it. Our mental health is just as important as our physical health, and support is available for all of those who need it. 


Although haemophilia A has a number of worrisome complications, prompt treatment of acute bleeds and adequate bleeding prophylaxis for those who need it can ensure haemophilia A patients experience the same quality of life as anyone else. Looking into the future, further research is important in developing better management options for patients with inhibitors. However, education is crucial for patients and their loved ones to recognise when to seek help. 


  1. nhs.uk [Internet]. 2017 [cited 2023 Aug 11]. Haemophilia. Available from: https://www.nhs.uk/conditions/haemophilia/
  2. Hemophilia - symptoms, diagnosis and treatment | bmj best practice us [Internet]. [cited 2023 Aug 12]. Available from: https://bestpractice.bmj.com/topics/en-us/468
  3. Berntorp E, Fischer K, Hart DP, Mancuso ME, Stephensen D, Shapiro AD, et al. Haemophilia. Nat Rev Dis Primers. 2021 Jun 24;7(1):45.
  4. Eyster ME, Gill FM, Blatt PM, Hilgartner MW, Ballard JO, Kinney TR. Central nervous system bleeding in hemophiliacs. Blood [Internet]. 1978 Jun 1 [cited 2023 Aug 15];51(6):1179–88. Available from: https://www.sciencedirect.com/science/article/pii/S0006497120747701
  5. Stromer W, Pabinger I, Ay C, Crevenna R, Donnerer J, Feistritzer C, et al. Pain management in hemophilia: expert recommendations. Wien Klin Wochenschr [Internet]. 2021 Oct 1 [cited 2023 Aug 13];133(19):1042–56. Available from: https://doi.org/10.1007/s00508-020-01798-4
  6. CDC. Centers for Disease Control and Prevention. 2020 [cited 2023 Aug 13]. What is hemophilia? | cdc. Available from: https://www.cdc.gov/ncbddd/hemophilia/facts.html
  7. Fijnvandraat K, Cnossen MH, Leebeek FWG, Peters M. Diagnosis and management of haemophilia. BMJ [Internet]. 2012 May 2 [cited 2023 Aug 18];344:e2707. Available from: https://www.bmj.com/content/344/bmj.e2707
  8. The Haemophilia Society [Internet]. [cited 2023 Aug 13]. Support. Available from: https://haemophilia.org.uk/support/ 
  9. Branca F. Physical activity, diet and skeletal health. Public Health Nutrition [Internet]. 1999 Mar [cited 2023 Aug 18];2(3a):391–6. Available from: https://www.cambridge.org/core/journals/public-health-nutrition/article/physical-activity-diet-and-skeletal-health/3FDF9968FFEB630636AEC9D123CA6E42
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

Get our health newsletter

Get daily health and wellness advice from our medical team.
Your privacy is important to us. Any information you provide to this website may be placed by us on our servers. If you do not agree do not provide the information.

Nell Marquess

Bachelor of Medicine, Bachelor of Surgery - MBBS, Medicine, University of Exeter

Nell is a medical student studying at the University of Exeter with an interest in psychiatry, general practice and women’s health. She has a background in teaching and has previously worked as an editor for a student medical journal. She is now writing medical articles for Klarity alongside her studies.

my.klarity.health presents all health information in line with our terms and conditions. It is essential to understand that the medical information available on our platform is not intended to substitute the relationship between a patient and their physician or doctor, as well as any medical guidance they offer. Always consult with a healthcare professional before making any decisions based on the information found on our website.
Klarity is a citizen-centric health data management platform that enables citizens to securely access, control and share their own health data. Klarity Health Library aims to provide clear and evidence-based health and wellness related informative articles. 
Klarity / Managed Self Ltd
Alum House
5 Alum Chine Road
Westbourne Bournemouth BH4 8DT
VAT Number: 362 5758 74
Company Number: 10696687

Phone Number:

 +44 20 3239 9818