Nikolsky's sign: is it 'dry' or is it 'wet'?

Nikolsky's signs refers to the ability to induce peripheral extension of a blister as a consequence of applying lateral pressure to the border of an intact blister. Although initially used in reference to the pemphigus group of blistering dermatoses, a positive Nikolsky's sign can be seen in other bullous diseases such as toxic epidermal necrolysis and staphylococcus scalded skin syndrome. Appreciating whether the blister is 'wet' or 'dry' at the site of a positive Nikolsky's signs may have both diagnostic and prognostic significance which I illustrate with several clinical cases. Lastly, I review the significance of a positive Nikolsky's sign.