Overview of Epidermolysis Bullosa
Epidermolysis bullosa (EB) is a term that refers to a group of inherited disorders characterized by blisters that occur spontaneously or develop as the result of pressure or friction. More than a dozen subtypes have been described. However, there are three main categories: simplex, junctional, and dystrophic, depending on the presence or absence of scarring and the level of separation and breakage within the skin.
In epidermolysis bullosa simplex, the level of separation (and hence blister formation) occurs within the top layer of the skin (epidermis), and scar formation does not occur. In junctional EB, the split occurs at the junction of the epidermis and the middle portion of the skin (dermis), and mild scarring can be seen. With dystrophic EB, the split and blister formation is deeper, and there can be extensive scarring. An acquired form, epidermolysis bullosa acquisita (EBA), occurs in adulthood and is usually associated with another disease, such as diabetes mellitus, tuberculosis, or colitis. Blisters usually develop on the hands and feet but can appear anywhere on the body, and there is scarring.
Mild varieties of epidermolysis bullosa may be seen in as many as 1 in 50,000 births; severe forms may occur at the rate of 1 in 500,000 births.