The rash that presents as a vesiculobullous eruption.

Various infections and autoimmune and reactive skin conditions can present with blisters of varying sizes. Some of these disorders are seen in everyday practice, whereas others are rarely encountered. In many cases, the clinical picture is so typical that the diagnosis is easy and obvious; nevertheless, the significant clinical overlap between many of these diseases can cause frustration in both unexperienced and expert clinicians. We present the most typical clinical clues and offer simplified algorithms to the clinical diagnosis of skin conditions with vesicles and bullae. We focus on several aspects, when assessing a patient with blisters on the skin: age of onset, a history of comorbidities and medications intake, the general condition of the patient, and most importantly, the distribution, number, size, morphology, and evolution of the blisters, the characteristics of the peribullous skin, and the presence of mucosal involvement. Emphasis is put on differentiating between potentially life-threatening blistering eruptions and more benign self-limiting conditions. © 2020 Elsevier Inc. All rights reserved.