Bullae are elevated, fluid-filled blisters ≥ 10 mm in diameter.
Pemphigus vulgaris usually occurs in middle-aged patients, affecting men and women in equal numbers. Rarely, cases have been reported in children. One variant, paraneoplastic pemphigus, can occur in patients who have malignant or benign tumors, most commonly non-Hodgkin lymphoma.
Pemphigus vulgaris is characterized by IgG autoantibodies directed against the calcium-dependent cadherins desmoglein 3 and sometimes desmoglein 1 (1). Paraneoplastic pemphigus has autoantibodies directed against these desmoglein antigens as well as others (eg, envoplakin, peiplakin, desmoplakin 1 and 2, BP-Ag 1). These transmembrane glycoproteins affect cell-cell adhesion and signaling between epidermal cells. Acantholysis (loss of intercellular adhesion with consequent epidermal blister formation) results from either direct inhibition of desmoglein function by autoantibody binding or from autoantibody-induced cell signaling that results in down-regulation of cell-cell adhesion. The autoantibodies are present in both serum and skin during active disease. Any area of stratified squamous epithelium may be affected, including mucosal surfaces (see figure Skin cleavage levels in pemphigus and bullous pemphigoid).
Skin cleavage levels in pemphigus and bullous pemphigoid
Pemphigus (vulgaris, foliaceus, or both) may coexist with certain central nervous system (CNS) disorders, especially dementia, epilepsy, and Parkinson disease. Desmoglein 1 is present in CNS neurons (and in all epithelial cells), and an immunologic cross-reaction between epithelial and CNS isoforms has been suggested.
1. Russo I, De Siena FP, MD, Saponeri A, et al: Evaluation of anti-desmoglein-1 and anti-desmoglein-3 autoantibody titers in pemphigus patients at the time of the initial diagnosis and after clinical remission. Medicine (Baltimore) 96(46):e8801, 2017. doi: 10.1097/MD.0000000000008801
Flaccid bullae, which are the primary lesions of pemphigus vulgaris, cause widespread and painful skin, oral, and other mucosal erosions. About half of patients have only oral erosions, which rupture and remain as chronic, painful lesions for variable periods. Often, oral lesions precede skin involvement. Dysphagia and poor oral intake are common because lesions also may occur in the upper esophagus. Cutaneous bullae typically arise in normal-appearing skin, rupture, and leave a raw area with crusting. Itching is usually absent. Erosions often become infected. If large portions of the body are affected, fluid and electrolyte loss may be significant.
Pemphigus vulgaris should be suspected in patients with unexplained chronic mucosal ulceration, particularly if they have bullous skin lesions. This disorder must be differentiated from other disorders that cause chronic oral ulcers and from other bullous dermatoses (eg, pemphigus foliaceus, bullous pemphigoid, mucous membrane pemphigoid, drug eruptions, toxic epidermal necrolysis, erythema multiforme, dermatitis herpetiformis, bullous contact dermatitis).
Two clinical findings, both reflecting lack of epidermal cohesion, that are somewhat specific for pemphigus vulgaris are the following:
The diagnosis of pemphigus vulgaris is confirmed by biopsy of lesional and surrounding (perilesional) normal skin. Immunofluorescence testing shows IgG autoantibodies against the keratinocyte's cell surface. Serum autoantibodies to desmoglein 1 and desmoglein 3 transmembrane glycoproteins can be identified via direct immunofluorescence, indirect immunofluorescence, and enzyme-linked immunosorbent assay (ELISA).
Referral to a dermatologist with expertise in treating this disorder is recommended. Hospitalization is required initially for all but the most minor cases. Cleansing and dressing of open skin lesions is similar to that done to treat partial-thickness burns (eg, reverse isolation, hydrocolloid or silver sulfadiazine dressings).
Treatment of pemphigus vulgaris is aimed at decreasing production of pathogenic autoantibodies. The mainstay of treatment is systemic corticosteroids. Some patients with few lesions may respond to oral prednisone 20 to 30 mg once a day, but most require 1 mg/kg once a day as an initial dose. Some clinicians begin with even higher doses, which may slightly hasten initial response but do not appear to improve outcome. If new lesions continue to appear after 5 to 7 days, IV pulse therapy with methylprednisolone 1 g once a day can be tried.
Once no new lesions have appeared for 7 to 10 days, corticosteroid dose should be tapered monthly by about 10 mg/day (tapering continues more slowly once 20 mg/day is reached). A relapse requires a return to the starting dose. If the patient has been stable after a year, a trial without treatment can be attempted but must be closely monitored.
Immunosuppressants such as rituximab (1), methotrexate, cyclophosphamide, azathioprine, gold, mycophenolate mofetil, or cyclosporine can reduce the need for corticosteroids and thus minimize the undesirable effects of long-term corticosteroid use. Rituximab combined with systemic corticosteroids is an alternative first-line treatment (2). Plasma exchange and high-dose IV immune globulin to reduce antibody titers have also been effective.
1. Craythorne EE, Mufti G, DuVivier AW: Rituximab used as a first-line single agent in the treatment of pemphigus vulgaris. J Am Acad Dermatol 65(5):1064–1065, 2011. doi: 10.1016/j.jaad.2010.06.033
2. Joly P, Maho-Vaillant M, Prost-Squarcioni C, et al: First-line rituximab combined with short-term prednisone versus prednisone alone for the treatment of pemphigus (Ritux 3): A prospective, multicentre, parallel-group, open-label randomised trial. Lancet 389(10083):2031–2040, 2017. doi: 10.1016/S0140-6736(17)30070-3
About half of patients with pemphigus vulgaris have only oral lesions.
Use Nikolsky and Asboe-Hansen signs to help clinically differentiate pemphigus vulgaris from other bullous disorders.
Confirm the diagnosis by immunofluorescence testing of skin samples.
Treat with systemic corticosteroids, with or without other immunosuppressive therapies (drugs, IV immune globulin, or plasma exchange).