This is a picture of microscopic polyarteritis on the shin. The term polyarteritis means that many blood vessels are inflamed. These nodules are located just below the skin's surface (subcutaneous), are barely felt when pressing on the skin (palpable), and are tender. The skin is typically red (erythematous).
Ariel D. Teitel, MD, MBA, Clinical Associate Professor of Medicine, NYU Langone Medical Center. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.