These spots of blood under the skin (purpura) are caused by vasculitis. They do not turn white with pressure (non-blanchable). In this particular case, the purpura are associated with an underlying disorder affecting the structure of the blood vessel walls (collagen-vascular disorder).
Neil J. Gonter, MD, Assistant Professor of Medicine, Columbia University, NY and private practice specializing in Rheumatology at Rheumatology Associates of North Jersey, Teaneck, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.