The separation is chiefly above the basal layer in the epidermis. Nikolsky's sign, or the ability to extend the margin of the bulla peripherally by pressure, is a diagnostic feature. The etiology is obscure, although a degeneration of the epidermal cell with loss of the intercellular bridges is an early feature. Oral lesions are almost always present, sometimes extensively, and the disease may start in the oropharynx. The bullae are flaccid and rupture easily, leaving a raw surface.
Systemic steroids are the method of choice for initial treatment.
If the process is not controlled in a week, the dose should be doubled and then stepped down gradually.