Wound care clinicians need to understand the normal function of the skin and how it may go awry leading to vesicles, blisters, and bullae. Wound care clinicians should be able to develop differential diagnoses for patients with possible allergic hypersensitivity, autoimmune diseases, and other skin disease that may be life threatening. This session will provide a systematic approach to assessing blisters, developing a differential diagnoses, and ordering/performing the appropriate diagnostic tests.