Pemphigus vulgaris Pemphigus vulgaris is a rare autoimmune, bullous disease that occasionally occurs during childhood. The disease affects both the skin and mucous membranes and can be life threatening. The typical lesions of pemphigus vulgaris are pictured in Fig. 17-1. Erosions of the lips, gums, tongue, and palate, as pictured here, are a common presenting symptom and may be misdiagnosed early in the course of the disease. The difficulty in chewing and swallowing that may occur can become a significant complication.

Cutaneous lesions consist of flaccid weeping blisters that quickly erode to leave large denuded areas of skin. Nikolsky sign, the extension of blistering by lateral finger pressure, is seen in the presence of widespread disease. Figure 17-2 shows the kind of crusting that develops as the blisters open. Antibodies to desmoglein 1 are associated with skin lesions and antibodies to desmoglein 3 are associated with oral lesions.

Pemphigus vulgaris The blisters of pemphigus vulgaris may arise on an erythematous base, or on normal-appearing skin, as pictured in Fig. 17-3. A variety of modalities have been employed in the treatment of this disease. The patient who is seriously ill requires hospitalization.

Figure 17-4 illustrates both intact blisters and superficial erosions. For most patients, the most rapidly effective treatment remains high-dose systemic steroids. Patients undergoing this form of therapy are at risk for infection and must be followed with extreme care. Rituximab, a monoclonal antibody against the B cell surface protein CD20, is the most promising new treatment for this disease. Immunosuppressive agents such as azathioprine, mycophenolate mofetil, intravenous immunoglobulin, and plasmapheresis are useful therapies.

Pemphigus vegetans When the cutaneous changes of pemphigus take place in intertriginous spaces, clear blistering is not evident. Rather, one sees boggy inflammation. The essential histologic process is again epidermal acantholysis, but blister roofs part almost at once and secondary infection is inevitable. This figure is a good representation of the kind of clinical appearance that develops in pemphigus vegetans. Lesions on other parts of the body take the form of pemphigus vulgaris.

Familial benign chronic pemphigus (Hailey-Hailey disease) This blistering disease is inherited in autosomal dominant fashion. Onset tends to occur during late adolescence. Patients with this disorder have a pruritic vesicular eruption in intertriginous areas that is worse during the summer months. Intact bullae may be absent, and often there is only an erosive and crusted intertrigo in the axillae, in the groin, and on the neck. Control of this condition is best achieved by the avoidance of the causative factor, such as heat or friction, and the treatment of superinfection when it occurs.

Subcorneal pustulosis (Sneddon-Wilkinson disease) This condition is most common during adulthood, but it does occur in children. Characteristically, crops of vesicles and pustules spring up and evolve into areas of superficial crusts and scales. As the lesions coalesce, they form the type of arcuate plaque that is illustrated in Fig. 17-7. The most common locations are the axillae, groin, and flexures of the upper and lower extremities. The lesions are often pruritic, and, especially in childhood, there may be fever and an elevated white blood count.

The etiology of this condition is completely unknown. Diagnosis is best confirmed by classic histologic appearance, which consists of collections of neutrophils just beneath the stratum corneum. The disease process is essentially benign, but dapsone is an effective therapy for the patient with frequent or severe recurrences.

Pemphigus foliaceus This form of pemphigus is less severe than pemphigus vulgaris because blister formation occurs higher in the epidermis. As a result, there is less compromise of vital cutaneous functions. In most areas of the world, pemphigus foliaceus is extremely unusual in children. In rural areas of Brazil, there is an endemic form of pemphigus foliaceus, termed fogo selvagem, which affects individuals of all ages.

Pictured in Figs. 17-9 and 17-10 are the typical lesions of pemphigus foliaceus. The disease often begins in the scalp with areas of erythema and scaling. As it progresses to involve the trunk and extremities, there evolve numerous crusting and erythematous plaques. Severe scaling is common, but usually there is no blister formation and no involvement of the oral cavity. Treatment consists of topical or systemic steroids, depending on the severity of the disease.

Pemphigus foliaceus Lesions in the perioral area, as seen in Fig. 17-11, are quite common. Oral mucosal involvement is less common, in contrast to pemphigus vulgaris. Often, patients with pemphigus foliaceus are initially thought to have recurrent impetigo, although the infection does not totally clear with appropriate antibiotics. It is important to realize that secondary infection often occurs in these patients, and this should be considered when patients have flare-ups or the disease is difficult to control.

Figure 17-12 shows annular lesions that are seen in childhood forms of pemphigus foliaceus. Direct immunofluorescence is important in making the diagnosis. In addition, antibodies to desmoglein, an epidermal desmosomal component, are found.