Severe generalized recessive dystrophic epidermolysis bullosa (RDEB-sev gen) is the most severe subtype of dystrophic epidermolysis bullosa (DEB, see this term), formerly known as the Hallopeau-Siemens type, and is characterized by generalized cutaneous and mucosal blistering and scarring associated with severe deformities and major extracutaneous involvement.

Distance between the commissures of the mouth more than 2 SD below the mean. Alternatively, an apparently decreased width of the oral aperture (subjective).