Pemphigus

Overview — What is Pemphigus?

Pemphigus is  a group of life-threatening blistering skin conditions that have the finding of acantholysis. Acantholysis is a loss of keratinocyte to keratinocyte adhesion that results in the formation of intraepithelial blisters in mucous membranes and skin]. The process of acantholysis is induced by the binding of circulating immunoglobulin G (IgG) autoantibodies to intercellular adhesion molecules. Patients with pemphigus develop mucosal erosions and/or flaccid bullae, erosions, or pustules on skin.

Forms of Pemphigus

There are four major entities of the pemphigus group which include:

  • pemphigus vulgaris

  • pemphigus foliaceus

  • immunoglobulin A (IgA) pemphigus

  • paraneoplastic pemphigus

These different forms of pemphigus are differentiated by their clinical features, associated autoantigens, and laboratory findings.

Pemphigus Vulgaris

Pemphigus vulgaris represents the most common form of pemphigus.  This is a rare condition that occurs between 0.1 and 0.5 per 100,000 people per year

Pemphigus Foliaceus

Pemphigus foliaceus is less common than pemphigus vulgaris. Endemic pemphigus foliaceus (fogo selvagem) contributes to the higher rate of pemphigus foliaceus in some countries such as in Brazil. The average age of onset of pemphigus is age 40 to 60 years for pemphigus vulgaris and nonendemic pemphigus foliaceus. Pemphigus is rare in children but endemic pemphigus foliaceus occurs in children and young adults in endemic areas.

IgA Pemphigus 

Data on IgA pemphigus is hard to study since so few cases and mainly occurs in females Paraneoplastic pemphigus is extremely rare. 

Causes of Pemphigus

The causes of pemphigus are not well understood. The most commonly accepted theory is that acantholysis is caused by the binding of autoantibodies to epithelial cell surface antigens through unknown mechanisms.

Clinical Features & Symptoms

Almost all patients with pemphigus vulgaris have mucus membrane disease. The mouth is the most common site of the lesions, but other sites can include the whites of the eyes, nose, esophagus, vulva, vagina, cervix, and anus. The blisters erode quickly.  The pain associated with mucosal involvement of pemphigus vulgaris can be severe and when the mouth is involved can lead to weight loss due to trouble eating. 

Diagnosis

The diagnosis of pemphigus is based upon the recognition of consistent clinical, histologic, and direct immunofluorescence (DIF) findings, as well as the detection of circulating IgG and IgA autoantibodies against cell surface antigens in the serum. Laboratory studies are useful for distinguishing pemphigus from other blistering and erosive diseases. The standard laboratory work-up for patients with clinical findings suggestive of pemphigus vulgaris or foliaceus can include a lesional skin or mucosal biopsy for routine hematoxylin and eosin staining, a  perilesional skin or mucosal biopsy for DIF, and serum collection for detection of autoantibodies by enzyme-linked immunosorbent assay (ELISA) and indirect immunofluorescence (IIF).