Which clinical sign helps IDENTIFY mucous membrane pemphigoid?

The Nikolsky sign (applying lateral pressure to normal-appearing skin/mucosa causes it to blister) is positive in pemphigus and MMP — indicates fragile, weakened epithelial-connective tissue junction due to basement membrane antibodies. Wickham's striae = lichen planus. Cobblestone = Crohn's. Fordyce spots = ectopic sebaceous glands. Nikolsky = vesiculobullous disease.