A positive Nikolsky’s sign (when slight rubbing of the skin results in immediate formation of a blister OR when pressure on the bulla results in extension of the blister to adjacent blistered skin) is indicative of toxic epidermal necrosis or pemphigus vulgaris. Toxic epidermal necrosis typically presents with a high fever and sheet-like epidermal detachment, whereas pemphigus vulgaris causes flaccid, intra-epidermal bullae.
Nikolsky’s sign is useful in differentiating between pemphigus vulgaris and bullous pemphigoid, which has tense, subepidermal bullae and a negative Nikolsky’s sign. Because of the deeper tissue involvement and greater risk of dehydration and secondary infection, pemphigus vulgaris is more serious than bullous pemphigoid.
This post was written by Omar Rifai