Which disease is more likely to present with oral mucosal involvement and a positive Nikolsky sign due to fragile bullae that rupture easily?

Which disease is more likely to present with oral mucosal involvement and a positive Nikolsky sign due to fragile bullae that rupture easily?

• A. Dermatitis herpetiformis
• B. Linear IgA disease
• C. Bullous pemphigoid
• D. Pemphigus vulgaris

Answer: (D)

The key idea is that this pattern points to pemphigus vulgaris, which is characterized by fragile, easily rupturing blisters and frequent oral mucosal involvement due to loss of keratinocyte adhesion. Autoantibodies attack desmosomes between epidermal cells (desmoglein 3, and sometimes desmoglein 1), causing acantholysis. This makes the bullae flaccid and shallow, so they rupture with minimal trauma, leaving painful erosions in the mouth and other mucosal surfaces. Because the blister is formed within the epidermis (intraepidermal), applying pressure or rubbing the skin causes the layers to separate, producing a positive Nikolsky sign. Other vesiculobullous diseases don’t fit this combination as neatly. Dermatitis herpetiformis involves intensely itchy vesicles on extensor surfaces, with mucosal involvement being uncommon and Nikolsky sign not typically positive. Linear IgA disease can involve mucosa but the blisters are not characteristically the fragile, easily rupturing type linked to acantholysis. Bullous pemphigoid features tense, subepidermal bullae that are less prone to rupture and usually spare mucosa, with a negative Nikolsky sign. So the presence of oral mucosal lesions, fragile bullae that rupture easily, and a positive Nikolsky sign best aligns with pemphigus vulgaris.

The key idea is that this pattern points to pemphigus vulgaris, which is characterized by fragile, easily rupturing blisters and frequent oral mucosal involvement due to loss of keratinocyte adhesion. Autoantibodies attack desmosomes between epidermal cells (desmoglein 3, and sometimes desmoglein 1), causing acantholysis. This makes the bullae flaccid and shallow, so they rupture with minimal trauma, leaving painful erosions in the mouth and other mucosal surfaces. Because the blister is formed within the epidermis (intraepidermal), applying pressure or rubbing the skin causes the layers to separate, producing a positive Nikolsky sign.

Other vesiculobullous diseases don’t fit this combination as neatly. Dermatitis herpetiformis involves intensely itchy vesicles on extensor surfaces, with mucosal involvement being uncommon and Nikolsky sign not typically positive. Linear IgA disease can involve mucosa but the blisters are not characteristically the fragile, easily rupturing type linked to acantholysis. Bullous pemphigoid features tense, subepidermal bullae that are less prone to rupture and usually spare mucosa, with a negative Nikolsky sign.

So the presence of oral mucosal lesions, fragile bullae that rupture easily, and a positive Nikolsky sign best aligns with pemphigus vulgaris.