Haemophilia A (factor VIII deficiency)

What it is

Hemophilia A is FVIII deficiency. It is a disorder of secondary hemostasis, the coagulation side, rather than of the primary platelet and VWF side.

How it presents

Coagulation bleeding does not look like platelet bleeding. Surface cuts give normal or only slightly prolonged bleeding, onset after injury is delayed rather than immediate, and the site of bleeding is deep - joints and muscles - with excessive post-traumatic bleeding. The lesions are hemarthroses and hematomas.

A primary platelet or VWF problem behaves the other way, and there bleeding after surface cuts is excessive and prolonged, onset is immediate, the sites are superficial and mucosal (nasal, gingival, GI tract, vaginal) and skin, and the lesions are petechiae and ecchymoses.