Nikolsky's sign

Nikolsky's sign is a clinical dermatological sign, named after the Russian physician Pyotr Nikolsky (1858–1940). The sign is positive when slight rubbing of the skin results in exfoliation of the outermost layer.

Nikolsky's sign is almost always present in toxic epidermal necrolysis^[5] and is associated with pemphigus vulgaris.^[6] It is useful in differentiating between pemphigus vulgaris (where it is present or positive) and bullous pemphigoid (where it is absent)