Background
The various types of pemphigus include pemphigus erythematosus, pemphigoid, pemphigus vegetans, pemphigus vulgaris, and pemphigus foliaceus.
Pemphigus erythematosus, also known as Senear-Usher syndrome, is an overlap syndrome with features of lupus erythematosus (LE) and pemphigus foliaceus. Pemphigus is demonstrated by acantholysis and immunoglobulin deposits in the interkeratinocyte substance (see the image below).
Direct immunofluorescence microscopy performed on epithelial biopsy specimen obtained from a patient with pemphigus vulgaris detects immunoglobulin G deposits at the epithelial cell surfaces.
Pérez-Pérez et al recently hypothesized that pemphigus erythematosus is a multiple autoimmune disease. [1]
High doses of UV light are suggested to be the cause of cleavage of the desmoglein-1 ectodomain. As in cases of pemphigus foliaceus the circulating anti–desmoglein-1 antibodies precipitate this cleaved off ectodomain along with the basement membrane zone, resulting in a lupus band–like appearance.
The lupus component of pemphigus erythematosus is demonstrated by circulating antinuclear antibodies (ANA) and sometimes by immunoglobulin and complement deposits at the dermoepidermal junction
For a thorough description and introduction to the possible causes of pemphigus, see the article "Pemphigus: An Acronym for a Disease with Multiple Causes ", published by the International Pemphigus Society. [2]
Pathophysiology
Patients with pemphigus erythematosus present with vesiculobullae or superficially eroded lesions, which may ooze and crust, particularly in sun-exposed areas, such as the face, the upper part of the chest, and the back.
Etiology
Patients with pemphigus develop an autoimmune response directed against desmosomes. [3] In patients with pemphigus foliaceus and its variant, pemphigus erythematosus, the target antigen is desmoglein 1. Desmogleins are desmosomal proteins important in keratinocyte adhesion. The binding of autoantibodies is postulated to result in a cascade of biochemical intracellular events that eventuates in the loss of desmosome function. Additionally, certain HLA haplotypes (A10 or A26, DRW6) are thought to be associated, suggesting a genetic predisposition.
Relapse of pemphigus erythematosus has been associated with atorvastatin intake. [4]
Epidemiology
Frequency
The incidence of pemphigus is 0.5-3.2 cases per 100,000 population per year. Patients with pemphigus erythematosus comprise only a small subgroup of those with pemphigus. Kumar from India, in a 2008 article, reported a high prevalence (4.4 cases per million population). [5]
Race
Pemphigus erythematosus, like other variants of pemphigus erythematosus and LE, may be increased in patients who express specific human leukocyte antigen (HLA) haplotypes. Those identified to have pemphigus erythematosus are positive for human leukocyte antigen A10 (HLA-A10) or human leukocyte antigen A26 (HLA-A26) and human leukocyte antigen DRW6 (HLA-DRW6).
Sex
Reports generally find no difference in occurrence of pemphigus erythematosus between the 2 sexes.
Age
Pemphigus erythematosus may occur at any age, but it is unusual in children.
Prognosis
The prognosis of pemphigus erythematosus is better than that of pemphigus vulgaris. With good dermatologic care, patients with pemphigus erythematosus are often able to live normal lives. Some patients may ultimately develop symptoms classified as criteria for systemic lupus erythematosus (SLE) by the American College of Rheumatology (ACR).
Patient Education
Patient education about possible triggers for the pemphigus erythematosus is important. Patients should minimize sun exposure. Additionally, as in all photosensitive disorders, patient education on the use of sunscreens, protective clothing, and sun-smart behaviors is a cornerstone of therapy.
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Direct immunofluorescence microscopy performed on epithelial biopsy specimen obtained from a patient with pemphigus vulgaris detects immunoglobulin G deposits at the epithelial cell surfaces.
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Biopsy shows moderate epithelial hyperplasia with a suprabasal cleft that shows suprabasal acantholysis. The rest of the epithelium shows spongiosis with neutrophils. The submucosa has a moderately dense mixed perivascular infiltrate of lymphocytes and neutrophils. At places, the epithelium is missing, and the surface is covered by fibrin and necrotic inflammatory cells. Photo courtesy of Dr. Uday Khopkar.
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Biopsy shows upper epidermal acantholytic blistering dermatitis involving the granular and upper spinous layer. The blister contains plasma, RBCs, and few acute inflammatory cells. The epidermis at the periphery of the blister shows mild spongiosis with neutrophils. In the roof of the blister, a few elongated acantholytic cells can be seen. Underlying dermis shows superficial and mid perivascular mixed infiltrate of neutrophils and lymphocytes. Photo courtesy of Dr. Uday Khopkar.
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Biopsy shows upper epidermal acantholytic blistering dermatitis involving the granular and upper spinous layer with absence of roof of blister. The epidermis shows mild spongiosis with neutrophils. Underlying dermis shows superficial and mid perivascular mixed infiltrate of neutrophils and lymphocytes. Photo courtesy of Dr. Uday Khopkar.
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Biopsy shows sparse superficial and deep perivascular infiltrate of lymphocytes. The papillary dermis is edematous and there is extravasation of RBCs. Basal layer shows vacuolization and interface infiltration by lymphocytes. Reticular dermis shows small amount of mucin. Photo courtesy of Dr. Uday Khopkar.
