Nikolsky's sign

Nikolsky's sign is a clinical dermatological sign, named after Pyotr Nikolsky (1858–1940), a Russian physician who trained and worked in Ukraine, which was part of the Russian Empire at that time. The sign is present when slight rubbing of the skin results in exfoliation of the outermost layer. A typical example would be to place the eraser of a pencil on the roof of a lesion and spin the pencil in a rolling motion between the thumb and forefinger. If the lesion is opened (skin sloughed off) then the Nikolsky's sign is present/positive.

Nikolsky's sign is almost always present in toxic epidermal necrolysis and is associated with pemphigus vulgaris. It is useful in differentiating between the diagnosis of pemphigus vulgaris or mucous membrane pemphigoid (where the sign is present) and bullous pemphigoid (where it is absent). The Nikolsky sign is dislodgement of intact superficial epidermis by a shearing force, indicating a plane of cleavage in the skin. The histological picture involves thinner, weaker attachments of the skin lesion itself to the normal skin - resulting in easier dislodgement. Also present in Staphylococcal scalded skin syndrome caused by the exfoliative toxin of Staphylococcus aureus.

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