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).
Review Date: 4/20/2013 Reviewed By: Gordon A. Starkebaum, MD, Professor of Medicine, Division of Rheumatology, University of Washington School of Medicine. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, Bethanne Black, Stephanie Slon, and Nissi Wang.