## Overview Purpura hemorrhagica is an immune-mediated vasculitis that usually follows strangles or influenza. Antigen-antibody complexes damage blood-vessel walls, causing leakage. Signs appear 2 to 4 weeks after infection and include severe edema of the limbs, head, and ventral abdomen, petechial hemorrhages on mucous membranes, fever, and depression. It is not contagious. ## Causes Type III hypersensitivity, most often after Streptococcus equi infection. ## Diagnosis History and clinical signs. Skin biopsy or bloodwork supports the diagnosis. ## Treatment Corticosteroids to suppress the immune reaction, plus antibiotics if active infection is present. Supportive care for edema. Most mild to moderate cases recover. ## Recovery and Prognosis Good for most cases with prompt treatment. Severe vasculitis can cause skin sloughing or organ damage. ## Prevention Appropriate strangles management. Avoid vaccination of horses with very high strangles titers in some protocols.
severe limb and ventral edema; petechial hemorrhages; fever; depression; often 2 to 4 weeks after strangles
## Overview Purpura hemorrhagica is an immune-mediated vasculitis that usually follows strangles or influenza. Antigen-antibody complexes damage blood-vessel walls, causing leakage. Signs appear 2 to 4 weeks after infection and include severe edema of the limbs, head, and ventral abdomen, petechial hemorrhages on mucous membranes, fever, and depression. It is not contagious. ## Causes Type III hypersensitivity, most often after Streptococcus equi infection. ## Diagnosis History and clinical signs. Skin biopsy or bloodwork supports the diagnosis. ## Treatment Corticosteroids to suppress the immune reaction, plus antibiotics if active infection is present. Supportive care for edema. Most mild to moderate cases recover. ## Recovery and Prognosis Good for most cases with prompt treatment. Severe vasculitis can cause skin sloughing or organ damage. ## Prevention Appropriate strangles management. Avoid vaccination of horses with very high strangles titers in some protocols.
severe limb and ventral edema; petechial hemorrhages; fever; depression; often 2 to 4 weeks after strangles