What is pemphigus vulgaris?

Pemphigus vulgaris is a rare autoimmune disease that is characterized by painful blisters and erosions on the skin and mucous membranes, most commonly inside the mouth. Pemphigus vulgaris accounts for 70% of all pemphigus cases worldwide although it is extremely rare in New Zealand (about one case per million of the population).

The other two main subtypes of pemphigus are pemphigus foliaceus and paraneoplastic pemphigus.

Who gets pemphigus vulgaris?

Pemphigus vulgaris affects people of all races, age, and sex. It most commonly appears between the ages of 30 and 60 years and is more common in Jews and Indians than in other races, presumably for genetic reasons.

Drug-induced pemphigus is also recognised and is most often caused by penicillamine, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and cephalosporins.

Pemphigus is sometimes triggered by cancer (paraneoplastic pemphigus), infection or trauma.

What causes pemphigus vulgaris?

Pemphigus vulgaris is an autoimmune blistering disease.

The keratinocytes are cemented together at unique sticky spots called desmosomes. In pemphigus vulgaris, immunoglobulin type G (IgG) autoantibodies bind to a protein called desmoglein 3 (dsg3), which is found in desmosomes in the keratinocytes near the bottom of the epidermis. The result is the keratinocytes separate from each other, and are replaced by fluid (the blister). About 50% of patients with pemphigus vulgaris also have anti-dsg1 antibodies.

What are the clinical features of pemphigus vulgaris?

Most patients with pemphigus vulgaris first present with lesions on the mucous membranes such as the mouth and genitals. Blisters usually develop on the skin after a few weeks or months, although in some cases, mucosal lesions may be the only manifestation of the disease.

Skin lesions appear as thin-walled flaccid blisters filled with clear fluid that easily rupture causing itchy and painful erosions. They most often arise on the upper chest, back, scalp, and face. Erosions in the skin folds may develop into vegetative lesions which are granular and crusted (pemphigus vegetans). The skin around the nails may be painful, red, and swollen.

The inside of the mouth is commonly involved in pemphigus vulgaris. Involvement of the pharynx and larynx cause pain on swallowing and a hoarse voice. Nasal involvement causes congestion and bleeding. The conjunctiva, oesophagus, labia, vagina, cervix, penis, urethra and anus may also be affected.

Features of oral mucosal pemphigus include:

  • Oral lesions in 50–70% of patients
  • Superficial blistering and erosions
  • Widespread involvement within the mouth
  • Painful, slow-to-heal ulcers
  • Spread to the larynx causing hoarseness when talking
  • Difficulty eating and drinking.

Information Source: DermNet NZ: https://dermnetnz.org/topics/pemphigus-vulgaris/