Pemphigus Foliaceus

The term “pemphigus” refers to a group of organ-specific, rare, autoimmune diseases that cause blistering of the skin.

Pemphigus foliaceus (PF) is the second most common form of pemphigus. It is considered to be less serious than pemphigus vulgaris, the most common form.

The lesions seen with pemphigus foliaceus are not as deep as those seen in pemphigus vulgaris. There is thus a lower risk of infection, fluid loss, and resulting metabolic abnormalities.

Pemphigus foliaceus is characterized by the formation of small blisters that form on apparently healthy skin over the face and the trunk. These increase in number and in some patients, they may be so numerous as to run together, resulting in exfoliative condition.

The condition may develop at any age, but disease onset occurs most commonly between the ages of 50 and 60 years. Unlike pemphigus vulgaris, pemphigus foliaceus is confined to the skin and does not involve mucous membranes of the mouth or throat.

Pathogenesis

The lesions form within the epidermal layers. The cells that make up the epidermis are called keratinocytes.

These are held together at sticky spots referred to as desmosomes. When a person has pemphigus foliaceus, autoantibodies develop in the blood.

These are directed against and bind to desmoglein, a protein component of these desmosomes.

This causes the keratinocytes to separate from one another and to be replaced by fluid, which leads to the development of blisters.

Since these blisters develop in the upper layers of the epidermis, they are covered by only a few superficial layers of cells. Thus they are flaccid and thin-walled, and burst easily. Many patients may present with erosions and no obvious blisters.

The blisters cause the skin to become itchy, and the erosions show crust formation from the inflammatory serous exudate.

The skin around the lesions appears red and inflamed. The condition is not usually painful, however. Blisters may form anywhere on the body in pemphigus foliaceus, but they generally tend to develop on the back, chest and shoulders.

Diagnosis

Pemphigus foliaceus is usually diagnosed by skin biopsy. Under a microscope, keratinocytes are found to be lying separately inside the blisters.

Diagnosis is confirmed using direct immunofluorescence staining, which reveals the presence of the autoantibodies that attack epidermis cells. Sometimes, a blood test may be used to detect antibodies in the circulation.

Treatment

Patients who are thought to have this condition should be referred to a dermatologist for diagnosis and management.

Sometimes, the condition resolves independently of treatment, while in other patients it persists over the long term. There is no cure for pemphigus foliaceus, but the condition can be managed and the symptoms controlled.

The main treatment approach for mild cases is the use of topical corticosteroids. However, the majority of cases are more severe and therefore require systemic treatment.

Patients are initially treated with a corticosteroid and once symptoms are under control, the dose is gradually reduced.

Simultaneously, another medication such as dapsone or azathioprine is used to prevent symptoms.

References

• http://www.pemphigus.org/research/clinically-speaking/pemphigus/
• http://www.mayoclinic.org/diseases-conditions/pemphigus/symptoms-causes/dxc-20157523
• http://www.pcds.org.uk/clinical-guidance/pemphigus-foliaceus
• http://www.aocd.org/?page=Pemphigus
• http://www.dermnetnz.org/immune/pemphigus-foliaceus.html