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 10/16/2017
Updated by: Jesse Borke, MD, FACEP, FAAEM, Attending Physician at FDR Medical Services/Millard Fillmore Suburban Hospital, Buffalo, NY. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.