Epidermolysis Bullosa at a Glance
- Family of inherited genodermatoses characterized by blistering in response to minor trauma
- Blistering level categories: simplex, junctional, and dystrophic subtypes
- Cutaneous involvement varies from localized to widespread blistering, depending on subtype
- Extracutaneous involvement varies from none to severely debilitating or lethal
- Oropharynx, trachea, esophagus, eyes, teeth, nails, hair can be involved, depending on subtype
- Diagnosis is made by immunofluorescent and/or electron microscopy followed by DNA analysis
Inherited epidermolysis bullosa (EB), is a family of diseases, with the common feature of blistering in response to mild trauma. Patients with EB can show blistering in the form of small vesicles or larger bullae, which can occur on both the cutaneous surfaces as well as on the mucosal tissues. The fragility of the skin and mucosa and the traumatic production of painful blisters are what all EB cases share in common. However, the distribution of the involvement, the depth of blister formation, any associated extracutaneous involvement and the severity of the blistering process vary with the different EB subtypes and depend on the underlying heritable molecular defect. Different EB subtypes also vary in the way in which blistered areas heal. The wound repair responses are often abnormal and can eventuate into chronic erosions, hypertrophic granulation tissue, scarring, or even invasive carcinoma. While the milder EB subtypes are associated with a normal lifespan and little or no internal involvement, the most severe recessively inherited forms are mutilating, multiorgan disorders that threaten both the quality and length of life.
A number of early studies identified the major subtypes of EB. Studies of von Hebra1–3 were the first to distinguish pemphigus from inherited blistering and the term epidermolysis bullosa hereditaria was first suggested by Koebner.4 Hallopeau was the first to distinguish between simplex (nonscarring) and dystrophic (scarring) forms of the disease5 while Weber6 and Cockayne,7 Dowling and Meara8 and Koebner4 each described unique forms of epidermolysis bullosa simplex. Hoffman,9 Cockayne,10 Touraine,11 Pasini,12 and Bart13 provided much of the information about subtypes of dystrophic epidermolysis bullosa. Herlitz described epidermolysis bullosa letalis,14 which was later found to be a part of the third major category of epidermolysis bullosa: the junctional form. The application of electron microscopy toward diagnosis of epidermolysis bullosa led to the studies of Pearson15 and collaborators who classified the patients not only on the basis of clinical findings but also on the existence of ultrastructural changes. A comprehensive classification of epidermolysis bullosa based on a combination of ultrastructural and clinical findings was completed in an early landmark treatise by Gedde-Dahl.16 Recent major advances have led to the identification of protein and genetic abnormalities in most types of epidermolysis bullosa patients. These studies have led to an improved understanding of the biological basis of epidermolysis bullosa and, finally, a classification of epidermolysis bullosa based on genetic/protein defects, which provides a rational approach ...