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.

Fusion of the hands and feet by a thin membrane of skin (scarring) seen in forms of dystrophic epidermolysis bullosa and leading to a \"mitten\" hand deformity.