Hematology and Blood Disorders

The vascular bleeding disorders are a heterogeneous group of conditions characterized by tranquil bruising, petechiae, ecchymosis, and mucosal and spontaneous bleeding from lesser vessels. The primary defect lies either in the vessels themselves or the perivascular connective tissue (eg, pseudoxanthoma elasticum, osteogenesis imperfecta, Marfan syndrome). Hemorrhage may be a protuberant feature of scurvy or of immunoglobulin A–associated vasculitis, a hypersensitivity vasculitis common during childhood.
Vascular defects affecting abnormal bleeding are rare. In cases of vitamin C deficiency (scurvy), capillary integrity is absent, and blood seeps into the tissues. In the organic condition hemorrhagic telangiectasia, groups of enormously dilated capillaries can be seen in the skin and mucous membranes of the mouth, nose, and gastrointestinal and respiratory tracts. The lesions look like in adult life and tend to bleed on the least provocation. Ehlers-Danlos syndrome is a disorder of collagen synthesis in which the enlarged fragility of vessels causes them to be easily ruptured. The use of cortisone, prednisolone, and additional glucocorticoid drugs are associated with increased capillary fragility and purpura (pinpoint hemorrhages in the skin and mucous membranes).