Master Pemphigus Vulgaris with Picmonic for Medicine

Desmosomes, also known as macula adherens, are protein complexes that aid in cell-to-cell adhesions by anchoring keratin cytoskeleton components in adjacent keratinocytes (squamous epithelial cells). The IgG autoantibodies in Pemphigus Vulgaris specifically target desmoglein, a type of cadherin protein, which has a transmembrane domain that aids in homophilic interactions to facilitate adjacent cell adhesion. These antibodies cause destruction, or acantholysis of the stratum spinosum, via a Type II Hypersensitivity reaction.

These are suprabasal fluid-filled blisters greater than 1 centimeter in size. In Pemphigus Vulgaris, they rupture easily because desmosome destruction occurs above the basement membrane, creating a thin-walled blister. After rupturing, the bullae turn to erosions with dried crust.

Because this mucosa is lined with squamous epithelium, bullae commonly appear in the oral cavity, causing difficulty while eating or speaking. The bullae may spread to the larynx, leading to voice hoarseness.

Acantholysis, the separation of keratinocytes due to desmosome destruction, occurs specifically in the stratum spinosum layer of skin.

If blood vessels underneath the skin are damaged, significant fluid loss can occur in these patients.

When bullae rupture, bacteria from the skin and environment may enter at these vulnerable sites, causing infection.

A positive Nikolsky sign indicates that when bullae are lightly touched, the superficial layers of skin separate from basolateral membrane, facilitated easy rupture.

Skin biopsy demonstrates autoantibody immunofluorescence surrounding the keratinocytes with a “net-like” pattern.

Administration of IVIG helps to suppress inflammation, with its effect lasting 2 to 3 months. The mechanism of action is unknown, but may involve binding the patient’s autoantibodies to prevent them from binding desmosomes. Plasmapheresis involves removing and replacing the patient’s plasma with donor plasma that does not contain the autoantibodies. Both treatment modalities help to prevent inflammation, infection, and fluid loss.

Because Pemphigus Vulgaris is an autoimmune condition, treatment is directed as suppressing the patient’s immune system to prevent further exacerbation of the condition. Moreover, inflammation is left behind after bullae rupture. Therefore patients may be treated with oral steroids, or other immunosuppressants, such as Rituximab, Mycophenolate, Azathioprine to suppress the immune system and alleviate inflammation.

Because Pemphigus Vulgaris is an autoimmune condition, treatment is directed as suppressing the patient’s immune system to prevent further exacerbation of the condition. Moreover, inflammation is left behind after bullae rupture. Therefore patients may be treated with oral steroids, or other immunosuppressants, such as Rituximab, Mycophenolate, Azathioprine to suppress the immune system and alleviate inflammation.