- Pemphigus Vulgaris is a autoimmune disease caused by direct antibody-mediated disruption of intra-epidermal connecting proteins and thus yielding intraepidermal blisters. The disease is acquired and onset is often in the third through sixth decades of life.
- Pemphigus Vulgaris is essentially a Type II Hypersensitivity process caused by inappropriate development of IgG auto-antibodies to Desmoglein 3, a major proteinacious component responsible for binding keratinocytes in the epidermis to one another. Binding of these antibodies disrupts the intracellular connection, yielding separation of keratinocytes and thus acantholysis.
- Acantholysis is the prototypical finding of pemphigus vulgaris and immunofluorescence studies reveal IgG and complement deposited in a basket-weave pattern surrounding keratinocytes throughout the epidermis. Intraepidermal separation of cells results, yielding bullae that occur right above the basal layer, leaving a neat ridge of unaffected epidermal basal cells that look like a line of "tomb stones".
- Because separation of keratinocytes occurs in the epidermis itself the resultant bullae have little structural integrity, rupture easily, and are thus termed "flaccid" bullae. Although clinically rare, affected skin displays "Nikolsky's Sign" which means that bullae easily extend into adjacent skin when lateral pressure is placed. Large areas of the skin can be affected, leaving denuded, crusting, erosions that can be life-threatening if not treated.
- Treatment of PV is evolving with modern biologics. Corticosteroids are the mainstay of therapy for acute flares but are typically accompanied by steroid-sparing immunosuppressants.