Nail disease may be the only finding and has prognostic value in management. Pemphigus foliaceus (PF) is the least severe of the three varieties. Desmoglein 1, the protein that is targeted by the autoantibodies, is enriched in the upper skin layers. PF is characterized by crusty sores that often begin on the scalp, and may move to the chest, back, and face. Mouth sores do not occur. This form is also frequent among Ashkenazi Jews. It is not as painful as PV, and is often misdiagnosed as dermatitis or eczema
Intraepidermal neutrophilic IgA dermatosis is characterized histologically by intraepidermal bullae with neutrophils, some eosinophils, and acantholysis. The least common and most severe type of pemphigus is paraneoplastic pemphigus (PNP). This disorder is a complication of cancer, usually lymphoma or Castlemans disease. It may precede the diagnosis of the tumor. Painful sores appear on the mouth, lips, and the esophagus. In this variety of pemphigus, the disease process often involves the lungs, causing bronchiolitis obliterans (constrictive bronchiolitis). Though much less frequent, it is still found the most in the Ashkenazi Jewish population. Complete removal of and/or cure of the tumor may improve the skin disease, but lung damage is generally irreversible. Endemic pemphigus foliaceus includes fogo selvagem, the new variant of endemic pemphigus foliaceus in El Bagre, Colombia, and the Tunisian endemic pemphigus in North Africa.Hailey-Hailey disease, also called familial benign pemphigus, is an inherited skin disease, not an autoimmune disease, so it is not considered part of the pemphigus group of diseases.
Diagnosis
Pemphigus defines a group of autoimmune intraepithelial blistering diseases that are characterized by loss of normal cell-cell adhesion (acantholysis), and by the presence of pathogenic (predominantly IgG) autoantibodies reacting against epithelial adhesion molecules. Pemphigus is further divided in two major subtypes: pemphigus vulgaris (PV) and pemphigus foliaceus (PF). However, several other disorders such as IgA pemphigus, IgE pemphigus, pemphigus herpetiformis, drug-induced pemphigus, Senear Usher syndrome, and endemic pemphigus foliaceus exist, and are recognized by a dermatologist from the appearance and distribution of the skin lesions. It is also commonly diagnosed by specialists practicing otolaryngology- head and neck surgery, periodontists, oral and maxillofacial surgeons, and eye doctors, as lesions can affect the eyes and mucous membranes of the oral cavity. Intraorally, it resembles the more common diseases lichen planus and mucous membrane pemphigoid. Definitive diagnosis requires examination of a skin or mucous membrane biopsy by a dermatopathologist or oral pathologist. The skin biopsy is taken from the edge of a blister, prepared for histopathology and examined with a microscope. The pathologist looks for an intraepidermal vesicle caused by the breaking apart of epidermal cells (acantholysis). Thus, the superficial (upper) portion of the epidermis sloughs off, leaving the bottom layer of cells on the "floor" of the blister. This bottom layer of cells is said to have a "tombstone" appearance. Definitive diagnosis also requires the demonstration of antidesmoglein autoantibodies by direct immunofluorescence on the skin biopsy. These antibodies appear as IgG deposits along the desmosomes between epidermal cells, a pattern reminiscent of chicken wire.