This is a 2 to 3 centimeter wide blood-filled (hemorrhagic) blister (bullae) that has resulted from an insect bite. It is located on the wrist. Bullae formation and tissue necrosis (death) are more common with spider bites, but may also be caused by insect bites.
Review Date 9/23/2019
Updated by: Jacob L. Heller, MD, MHA, Emergency Medicine, Emeritus, Virginia Mason Medical Center, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.