"Spontaneous" ecchymoses were noted in a case of purpura factitia. They occurred in easily accessible parts of the body without evidence of trauma. Histologic findings in areas of hemorrhage were insignificant. With a number of antigens, skin-sensitivity tests were positive, provided the antigens were injected in accessible areas, and the patient was informed of the expected result of the test. Protecting an area with a cast or a thigh bandage resulted in freedom from ecchymoses. Criteria of differential diagnosis between purpura factitia and auto-erythrocyte sensitization purpura are analyzed.
Stefanini M, Baumgart ET. Purpura FactitiaAn Analysis of Criteria for Its Differentiation From Auto-Erythrocyte Sensitization Purpura. Arch Dermatol. 1972;106(2):238-241. doi:10.1001/archderm.1972.01620110070018