Last updated: March 23, 2022

Summarytoggle arrow icon

Hemophilias are disorders of blood clotting and consequently may lead to serious bleeding. In the majority of cases, these disorders are hereditary. There are three types of hemophilia, determined based on which clotting factor is deficient: hemophilia A (factor VIII), hemophilia B (factor IX), and hemophilia C (factor XI). All types result in impaired secondary hemostasis (plasmatic coagulation) that manifests as increased activated partial thromboplastin time (aPTT). Hemophilia presents with hemarthrosis (bleeding into joints) and muscular or soft tissue hematomas. Depending on the remaining clotting factor activity, bleeding may occur spontaneously or in response to trauma of varying severity. Repeated hemarthrosis can eventually lead to joint destruction, a serious long-term complication of hemophilia. Diagnosis is based on patient history and a mix of semiquantitative and quantitative measurements of clotting factor activity. Severe hemophilia (enzyme activity < 1%) is treated with prophylactic substitution of clotting factors, whereas mild hemophilia A, in particular, can also be treated with desmopressin, a synthetic vasopressin analog.

Epidemiologytoggle arrow icon

Epidemiological data refers to the US, unless otherwise specified.

Etiologytoggle arrow icon

Hemophilia is caused by an X-linked recessive defect (inherited or spontaneous mutation) or antibody production against clotting factors.

Hemophilia usually affects males, as it is primarily an X-linked recessive disease.

Clinical featurestoggle arrow icon

  • Spontaneous bleeding or delayed-onset bleeding (joints, muscular and soft tissue, mucosa) in response to different degrees of trauma
  • Further sites/symptoms of hemorrhage:
  • Female carriers may show mild symptoms.
  • The degree of bleeding and, therefore, severity of hemophilia depends on residual factor activity levels; normal reference activity is > 50%
Severity Clinical signs Factor VIII or IX activity
Mild hemophilia Hematomas following severe trauma > 5% to < 50%
Moderate hemophilia Hematomas following mild trauma ≥ 1% to 5%
Severe hemophilia Spontaneous hematomas < 1%

Petechial bleeding is a common sign of platelet disorders, but NOT of coagulation disorders such as hemophilia.

Diagnosticstoggle arrow icon

Treatmenttoggle arrow icon

Referencestoggle arrow icon

  1. Mohammed BM, Matafonov A, Ivanov I, et al. An update on factor XI structure and function. Thromb Res. 2018; 161: p.94-105.doi: 10.1016/j.thromres.2017.10.008 . | Open in Read by QxMD
  2. Witmer C, Young G. Factor VIII inhibitors in hemophilia A: rationale and latest evidence. Therapeutic Advances in Hematology. 2012; 4 (1): p.59-72.doi: 10.1177/2040620712464509 . | Open in Read by QxMD
  3. Candy V, Whitworth H, Grabell J, et al. A decreased and less sustained desmopressin response in hemophilia A carriers contributes to bleeding. Blood Advances. 2018; 2 (20): p.2629-2636.doi: 10.1182/bloodadvances.2018023713 . | Open in Read by QxMD
  4. Data & Statistics on Hemophilia. Updated: September 14, 2020. Accessed: September 24, 2021.

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 Evidence-based content, created and peer-reviewed by physicians. Read the disclaimer