Dystrophic epidermolysis bullosa.

The three forms of dystrophic epidermolysis bullosa include the autosomal recessive form and two autosomal dominant variants, the Cockayne-Touraine and Pasini forms. Whereas all three forms are clinically characterized by milia, nail dystrophy, and scarring, the autosomal recessive form tends to be the most mutilating with frequent mucosal lesions. The Pasini variant often has generalized blistering commonly associated with mucosal involvement but to a lesser degree. The Cockayne-Touraine variant is usually localized to the extremities and tends to be the mildest form of dystrophic epidermolysis bullosa. Ultrastructurally, the blister is located below the basal lamina in all three variants. The anchoring fibrils are either absent or hypoplastic in each condition. The autosomal recessive form alone also demonstrates dermal collagenolytic activity. The ultrastructural differentiation between the two forms of the dominant dystrophic epidermolysis bullosa depends on a quantitative rather than qualitative assessment of the anchoring fibrils.