What Is Hemophilia A?

A Bleeding Disorder That Can Be Managed With Treatment

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Hemophilia A is a disorder that makes a person predisposed to bleeding. This can cause issues ranging from prolonged bleeding from a minor wound to bleeding emergencies. The condition is caused by a deficiency in factor VIII (or factor 8), which is a protein that helps the body form blood clots.

Hemophilia A can be hereditary or acquired. It is not curable, and several treatments are used to help prevent bleeding.

This article will discuss the symptoms and causes of hemophilia A, as well as review the diagnostic process, treatment options, and disease prognosis.

Symptoms of Hemophilia A

Verywell / Ellen Lindner

Types of Hemophilia A 

There are two types of hemophilia A: hereditary and acquired.

  • Hereditary hemophilia A: This condition occurs when a person inherits a gene that prevents proper formation of factor VIII. The effects and symptoms of the hereditary type begin at birth or during early childhood.
  • Acquired hemophilia A: This condition occurs when the body’s immune system attacks factor VIII. It usually begins during adulthood, after age 50.

Symptoms of Hemophilia A

Bleeding is the primary effect of hemophilia A. Bleeding can occur without any injury or after any mild or severe injury. The condition causes internal bleeding and external bleeding. Internal bleeding can cause bruises, lumps in the body, joint swelling, joint damage, and, potentially, organ damage.

Common symptoms include:

Blood Loss

Without treatment, bleeding may also cause serious blood loss, and it can be fatal.


Hemophilia A occurs when there is a decreased amount of factor VIII in the body. This protein is part of the body’s natural blood-clotting cascade, the set of actions that leads to clotting. When blood does not clot properly, bleeding may occur. 


Hereditary hemophilia A is inherited with an X-linked pattern. It occurs when a person inherits a mutation in the F8 gene, which is a gene on the X chromosome that codes for the production of factor VIII.

This is a recessive gene defect, which means that a person must have no properly working copies of the gene to have the effects of hereditary hemophilia A.

Most females have two X chromosomes, and most males have only one X chromosome. This means that males who inherit the mutated gene will have effects of the condition, while females who inherit only one copy of the mutated gene are unlikely to have effects of the condition.


The acquired form of hemophilia A develops due to antibodies (immune proteins) that the body’s immune system makes against a person’s own factor VIII. Risk factors for developing these antibodies include cancer and autoimmune disease, but the condition can develop without these risk factors.


Hemophilia A is diagnosed based on a measurement of factor VIII in the blood. The amount of this factor can vary in hemophilia A, and a very low amount corresponds to severe disease, while a moderately low amount corresponds to mild disease.

Sometimes bleeding tests are abnormal as well, although this is not diagnostic of hemophilia A. For example, regarding two of the tests used to measure the time it takes for blood to clot, partial thromboplastin time (PTT) is prolonged in hemophilia A, and prothrombin time (PT) is normal. These tests might be ordered to evaluate excessive bleeding before specific tests are done to measure factor VIII.

Genetic Test

A genetic test can identify the mutation in people who have the condition. It can also be used to determine whether you are a carrier, even if you are not symptomatic. Sometimes genetic testing is done for screening purposes when a baby is at risk of inheriting the disease.

It may also be done to identify the cause of bleeding when someone is symptomatic. People who have the acquired form of the condition do not have the genetic abnormality.


There are several treatments available for hemophilia A. Factor VIII replacements are the cornerstone of treatment. These treatments are infused into a vein, and they can include products made from human blood or artificially produced products.

Other treatments include Hemlibra (emicizumab), a factor VIII mimic; desmopressin (DDAVP), which prevents bleeding; and Amicar (aminocaproic acid), which prevents the breakdown of blood clots.

Some people develop inhibitors against factor VIII replacement after getting the treatment for a while and may need to receive emicizumab or immune therapy. Over time, the inhibitors may decrease.

Treatments may also be needed for bleeding complications.

Recurrent bleeding into the joints can cause pain and reduce mobility. This can be treated with physical therapy and exercises.


Hemophilia A is a lifelong condition, and it is not curable. Your prognosis depends on the severity of your condition and your response to treatment. Some people only experience mildly increased bleeding after injuries, but the disorder can cause serious bleeding episodes.


Living with hemophilia A can be stressful. You need to be cautious about bleeding risks and follow up with your needed treatments. It’s important to stay active to build muscle strength and balance—which can help prevent injuries.

If you are dealing with anxiety, uncertainty, or a sense of isolation due to your condition, it’s helpful to reach out for counseling or join a support group so you can learn practical ways to cope and live your best life.


Hemophilia A can cause major and minor bleeding episodes. The condition occurs when someone has a lower-than-normal level of factor VIII. You or your child might have a genetic test or a factor VIII level test as part of the diagnostic process if you develop symptoms or are at risk of this condition.

While there is no cure, treatments can improve your quality of life and reduce the severity and frequency of bleeding episodes. The most common treatments are factor VIII replacements and Hemlibra (emicizumab), which mimics factor VIII. Some people develop an immune reaction to factor VIII replacement, and this problem requires special treatment.

Living with hemophilia A means that you need to make some adjustments in your life to avoid injuries and to make time for your necessary treatments.

A Word From Verywell

You can live a healthy and active life with hemophilia A. The treatments are beneficial, and you can also take part in many activities that have a low risk of bleeding.

While you must avoid bleeding, you can be treated even if you experience a bleeding episode. It’s important to have a thorough understanding of your disease so you can be empowered to maintain your best health.

3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Levy-Mendelovich S, Brutman-Barazani T, Budnik I, Avishai E, Barg AA, Levy T, Misgav M, Livnat T, Kenet G. Real-world data on bleeding patterns of hemophilia A patients treated with emicizumab. J Clin Med. 2021 Sep 22;10(19):4303. doi:10.3390/jcm10194303

  2. Deniz V, Guzel NA, Lobet S, Antmen AB, Sasmaz HI, Kilci A, Boyraz OC, Gunaştı O, Kurdak SS. Effects of a supervised therapeutic exercise program on musculoskeletal health and gait in patients with haemophilia: A pilot study. Haemophilia. 2021 Oct 22. doi:10.1111/hae.14444

  3. Di Minno G, Coppola A, Margaglione M, Rocino A, Mancuso ME, Tagliaferri A, Linari S, Zanon E, Santoro C, Biasoli C, Castaman G, Santagostino E, Mannucci PM; AICE PROFIT Study Group. Predictors of inhibitor eradication by primary immune tolerance induction in severe haemophilia A with high responding inhibitors. Haemophilia. 2021 Nov 2. doi:10.1111/hae.14431

By Heidi Moawad, MD
Heidi Moawad is a neurologist and expert in the field of brain health and neurological disorders. Dr. Moawad regularly writes and edits health and career content for medical books and publications.