Recessive Dystrophic Epidermolysis Bullosa: A Clinical Overview

Abstract

Recessive dystrophic epidermolysis bullosa (EB) is defined as a mechanobullous disease with dermolytic separation (i.e., separation at the basement membrane zone deep to the lamina densa) and recessive inheritance. Ultimately, the diagnosis depends on confirmation of the level of separation by ultrastructural examination (Fig. 9.1), antigen mapping, or preferably both.1–6 This disorder has also been called dermolytic EB to emphasize the importance of the level of separation on the dermal side of the lamina densa.3 Dystrophic scarring is a distinctive feature in these patients and serves as a useful clinical marker. It must be remembered, however, that dystrophic scarring may be seen in some of the other types of EB, particularly in junctional EB in areas of healed granulation tissue and in some special subvariants of that disease.7 All forms of dystrophic EB follow simple mendelian inheritance patterns being either autosomal dominant or autosomal recessive. It is traditional to classify dystrophic EB into recessive and dominant types. A clear-cut inheritance pattern can be recognized in many families by the presence of multiple affected siblings in a family with normal parents. History of consanguinity further supports recessive inheritance. However, sporadic cases are common, in which case it is often difficult to distinguish between recessive inheritance and spontaneous mutation in a dominantly inherited disease. For example, distinguishing between dominant epidermolysis bullosa dystrophica (EBD) and localized recessive EBD may be particularly difficult.