Pemphigus Vulgaris

Pemphigus vulgaris is an autoimmune blistering disorder in which IgG autoantibodies disrupt desmogleins, the adhesion proteins that hold neighboring keratinocytes together. Desmoglein 3 is especially important in mucosal epithelium; desmoglein 1 contributes to adhesion in the superficial epidermis. When both are targeted, disease involves mucous membranes and skin. Loss of keratinocyte adhesion produces acantholysis and a split within the epidermis, just above the basal layer. The resulting bullae are therefore flaccid, not tense. They rupture with minor contact and leave shallow, painful erosions that may be more clinically obvious than the original blisters. A positive Nikolsky sign may occur, meaning light lateral pressure causes superficial epidermal separation, but deliberately provoking fragile skin is unnecessary and can enlarge an erosion. Oral lesions are common and may precede skin findings. Painful erosions can involve the mouth, pharynx, esophagus, nose, genitals, or eyes. Dysphagia, odynophagia, and oral pain can reduce intake long before laboratory abnormalities appear. With extensive disease, the denuded surface loses fluid and protein, the barrier against microorganisms is impaired, and systemic corticosteroid or other immunosuppressive therapy further increases infection risk....