Hemophilia A symptoms

Dive into the details of hemophilia A signs and symptoms, which can all vary depending on the individual.

Signs and symptoms of hemophilia A

Hemophilia A symptoms can include1,2:

Signs and symptoms of hemophilia A vary with the individual. If your clotting-factor level is mildly reduced, you might bleed only after serious trauma.

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Excessive bleeding or bruising in the joints, muscles, or soft tissue

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Pain, swelling, or tightness in joints

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Bleeding of the mouth and gums and bleeding after losing a tooth

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Bleeding from an injury or medical procedure

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Bleeding in the head of an infant after a difficult delivery

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Blood in the urine or stool

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Frequent and hard-to-stop nosebleeds

If your clotting-factor level is greatly reduced, though, you can bleed easily from a small cut, or even for seemingly no reason. A bump on the head can even cause bleeding into the brain for some people. This is rare, but it's one of the most serious complications that can occur.


Mild, moderate, or severe hemophilia A3

A person can have mild, moderate, or severe hemophilia A. It depends on how much working clotting factor is in the blood. The standard factor level is 100%. You can have a factor level between 50% and 150% and still be considered normal. In a person with hemophilia A, the clotting factor level is much lower than the standard.

Mild Hemophilia A

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Mild hemophilia A
6% to 49% working factor VIII

  • Bleeding only after serious: trauma, injury, surgery
  • First episode may not occur until adulthood
  • Women may experience heavy menstrual bleeding, hemorrhage during childbirth

Moderate Hemophilia A

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Moderate hemophilia A
1% to 5% factor level

  • Bleeding after injuries or trauma

Severe Hemophilia A

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Severe hemophilia A
Less than 1% factor level

  • Bleeding after injuries and spontaneously with no obvious cause (often into muscles and joints)
  • Boys with severe hemophilia A are often diagnosed after circumcision

Keep exploring

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What causes hemophilia A?

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Treatment options for hemophilia A

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What are the severity levels of hemophilia A?

  1. Srivastava A, Santagostino E, Dougall A, et al. WFH Guidelines for the Management of Hemophilia, 3rd edition. Haemophilia. 2020:26(suppl 6):1-158. https://doi.org/10.1111/hae.14046
  2. Mayo Clinic. Hemophilia. https://www.mayoclinic.org/diseases-conditions/hemophilia/symptoms-causes/syc-20373327. Accessed February 12, 2023.
  3. National Hemophilia Foundation. Hemophilia A. https://www.hemophilia.org/Bleeding-Disorders/Types-of-Bleeding-Disorders/Hemophilia-A. Accessed February 12, 2023.