Pemphigus - Blistering Diseases

PEMPHIGUS

Pemphigus is a group of serious diseases of the skin characterized by the appearance of bullae (ie, blisters) of various sizes on ap-parently normal skin (Fig. 56-5) and mucous membranes. Avail-able evidence indicates that pemphigus is an autoimmune disease involving immunoglobulin G. It is thought that the pemphigus antibody is directed against a specific cell-surface antigen in epi-dermal cells. A blister forms from the antigen–antibody reaction. The level of serum antibody is predictive of disease severity. Ge-netic factors may also play a role in its development, with the highest incidence among those of Jewish or Mediterranean de-scent. This disorder usually occurs in men and women in middle and late adulthood. The condition may be associated with peni-cillins and captopril and with myasthenia gravis.

Clinical Manifestations

Most patients present with oral lesions appearing as irregularly shaped erosions that are painful, bleed easily, and heal slowly. The skin bullae enlarge, rupture, and leave large, painful eroded areas that are accompanied by crusting and oozing. A character-istic offensive odor emanates from the bullae and the exuding serum. There is blistering or sloughing of uninvolved skin when minimal pressure is applied (ie, Nikolsky’s sign). The eroded skin heals slowly, and huge areas of the body eventually are involved. Bacterial superinfection is common.

Complications

The most common complications of pemphigus vulgaris arise when the disease process is widespread. Before the advent of corticosteroid and immunosuppressive therapy, patients were very susceptible to secondary bacterial infection. Skin bacteria have relatively easy ac-cess to the bullae as they ooze, rupture, and leave denuded areas that are open to the environment. Fluid and electrolyte imbalance re-sults from the loss of both fluid and protein as the bullae rupture. Hypoalbuminemia is common when the disease process includes extensive areas of the body skin surface and mucous membranes.

Management

The goals of therapy are to bring the disease under control as rapidly as possible, to prevent loss of serum and the development of secondary infection, and to promote re-epithelization (ie, re-newal of epithelial tissue).

Corticosteroids are administered in high doses to control the disease and keep the skin free of blisters. The high dosage level is maintained until remission is apparent. In some cases, cortico-steroid therapy must be maintained for life.

Corticosteroids are administered with or immediately after a meal and may be accompanied by an antacid as prophylaxis against gastric complications. Essential to therapeutic manage-ment are daily evaluations of body weight, blood pressure, blood glucose levels, and fluid balance. High-dose corticosteroid ther-apy has its own serious toxic effects.

Immunosuppressive agents (eg, azathioprine, cyclophospha-mide, gold) may be prescribed to help control the disease and reduce the corticosteroid dose. Plasmapheresis (ie, plasma ex-change) temporarily decreases the serum antibody level and has been used with variable success, although it is generally reserved for life-threatening cases.