Introduction
Synonyms: Fogo selvagem: endemic pemphigus foliaceus; Brazilian pemphigus Pemphigus erythematosus: Senear–Usher syndrome IgA pemphigus: intercellular IgA dermatosis; intraepidermal neutrophilic IgA dermatosis; intercellular IgA vesiculopustular dermatosis Paraneoplastic pemphigus: paraneoplastic autoimmune multi-organ syndrome
Key features
Pemphigus is a group of autoimmune blistering diseases of the skin and mucous membranes that is characterized by:
histologically, intraepidermal blisters due to the loss of cell–cell adhesion of keratinocytes immunopathologically, the finding of in vivo bound and circulating IgG autoantibodies directed against the cell surface of keratinocytes
Pemphigus is divided into three major forms: pemphigus vulgaris, pemphigus foliaceus, and paraneoplastic pemphigus
The functional inhibition of desmogleins, which play an important role in cell–cell adhesion of keratinocytes, by IgG autoantibodies results in blister formation
Patients with pemphigus vulgaris and pemphigus foliaceus have
IgG autoantibodies against desmoglein 3 and desmoglein 1, respectively, while patients with paraneoplastic pemphigus also have IgG autoantibodies against plakin molecules as well as a T cell-mediated autoimmune reaction that leads to an interface dermatitis
IgA pemphigus is characterized by IgA, but not IgG, autoantibodies directed against keratinocyte cell surfaces and is divided into two major subtypes: intraepidermal neutrophilic (IEN) type and subcorneal pustular dermatosis (SPD) type
Systemic corticosteroids are a mainstay of therapy in pemphigus vulgaris, given the rapidity of clinical response, but because of their potential side effects at effective doses, they are combined with steroid-sparing agents
These additional therapies include immunosuppressive medications such as mycophenolate mofetil, high-dose IVIg (non-immunosuppressive), and anti-CD20 monoclonal antibodies
Rituximab represents a first-line, FDA-approved therapeutic option for moderate-to-severe pemphigus and can also benefit patients who do not achieve clinical remission with systemic corticosteroids and/or other adjuvant immunosuppressive drugs