Pemphigus Vulgaris
A severe autoimmune condition causing painful, easily broken blisters and sores on the skin and inside the mouth.
Emergency Management: Severe, widespread flares (>30% Body Surface Area) require hospitalization, aggressive fluid/electrolyte resuscitation, IV corticosteroids (Methylprednisolone pulse therapy 1g/day for 3 days), and meticulous wound care.
Pemphigus vulgaris is a rare, severe, and potentially life-threatening autoimmune blistering disease affecting the skin and mucous membranes. It is characterized by the formation of flaccid, easily ruptured intraepidermal blisters and widespread painful erosions.
Detailed Overview
The disease is caused by IgG autoantibodies targeting desmogleins, which are critical adhesion proteins in desmosomes that hold epidermal cells together. This causes acantholysis (loss of cell-to-cell adhesion). Mucosal involvement (especially the oral cavity) is almost universal and often precedes skin lesions by months. Prior to the advent of systemic corticosteroids, PV was almost uniformly fatal due to fluid loss and sepsis.
Epidemiology & Demographics
Rare, with an incidence of 0.1 to 0.5 per 100,000 annually. It most commonly affects individuals between 40 and 60 years of age. Higher prevalence in people of Ashkenazi Jewish, Mediterranean, or Indian descent.
Etiological Mechanism
An autoimmune reaction where B cells produce IgG antibodies against epidermal desmogleins. Genetic predisposition (specific HLA class II alleles) is strongly implicated.
Primary Causes
Production of anti-Desmoglein 3 (Dsg3) and anti-Desmoglein 1 (Dsg1) autoantibodies. Certain drugs (penicillamine, captopril) can rarely induce pemphigus.
IgG autoantibodies bind to the extracellular domain of Desmoglein 3 (found in the lower epidermis and mucosa) and Desmoglein 1 (found in the upper epidermis). This binding sterically hinders desmosome formation or triggers intracellular signaling that depletes desmosomes. This results in 'acantholysis', where keratinocytes detach from one another. Because the basal layer remains attached to the basement membrane via hemidesmosomes (which are not targeted), a 'tombstone row' appearance is seen histologically. The resulting blister is superficial (suprabasal) and therefore very fragile.
Diagnostic Criteria & Guidelines
Diagnosis requires clinical suspicion confirmed by three tests: 1) Histopathology of a lesion showing suprabasal acantholysis, 2) Direct Immunofluorescence (DIF) of perilesional normal skin showing intercellular IgG/C3 deposits in a net-like pattern, and 3) Serology (ELISA) positive for circulating anti-Dsg3 and/or anti-Dsg1 autoantibodies.
Rituximab (anti-CD20 monoclonal antibody; 1000 mg IV on days 1 and 15) combined with high-dose systemic Corticosteroids (Prednisone 1-1.5 mg/kg/day PO). The corticosteroids are rapidly tapered once disease control is achieved, relying on Rituximab for long-term remission.
Second-Line & Adjunctive Therapy
For Rituximab failures or contraindications: Immunosuppressants such as Azathioprine (2-3 mg/kg/day PO) or Mycophenolate Mofetil (2 g/day PO). IVIG or Plasmapheresis for severe, rapidly progressive, refractory disease.
Surgical & Procedural Management
Not applicable for primary disease. Meticulous wound care is essential, similar to burn unit management for severe cases.
Patient Counseling & Advice
Warn that healing is slow, and blisters take weeks to resolve. Counsel extensively on the risks of immunosuppression, including the absolute necessity of seeking immediate medical care for fever or signs of infection.
Follow-Up & Monitoring Schedule
Monthly visits during active disease to assess mucosal/skin healing and taper steroids. Monitor anti-Dsg antibody titers via ELISA every 3-6 months to predict clinical relapses. Dexa scan to monitor for steroid-induced osteoporosis.
Preventive Strategies
No primary prevention. Avoidance of known drug triggers in susceptible individuals.
Before steroids, mortality was >90%. Today, mortality is around 5%, mostly due to infectious complications of immunosuppressive therapy. Many patients achieve complete remission off therapy with Rituximab.