Bleeding may result from abnormalities in
Vascular bleeding disorders result from defects in blood vessels, typically causing petechiae, purpura, and bruising but, except for hereditary hemorrhagic telangiectasia, seldom leading to serious blood loss. Bleeding may result from deficiencies of vascular and perivascular collagen in Ehlers-Danlos syndrome and in other rare hereditary connective tissue disorders (eg, pseudoxanthoma elasticum, osteogenesis imperfecta, Marfan syndrome). Hemorrhage may be a prominent feature of scurvy or of immunoglobulin A–associated vasculitis, a hypersensitivity vasculitis common during childhood.
In vascular bleeding disorders, tests of hemostasis are usually normal. For most disorders, diagnosis is clinical; specific tests are available for some.
