Pretibial epidermolysis bullosa: A clinicopathologic study

Abstract

Pretibial epidermolysis bullosa (PEB) is a rare variant of dystrophic epidermolysis bullosa (DEB) that predominantly involves the pretibial skin. We report 19 cases of DEB with pretibial predilection and our findings on anchoring fibrils. Patients with blisters and scars that primarily involved the pretibial were selected. Blisters and noninvolved skin were studied by light and electron microscopy. Anchoring fibrils were quantified by morphometry. There were 19 patients from 13 families. The inheritance was autosomal dominant in 10 families and sporadic in one family, and sibling involvement was present in two families. Nail dystrophy was noted in all patients. Pruritus was a common feature. Extensive prurigo occurred in four patients. Eight patients had skin lesions that exclusively affected the legs and were diagnosed as PEB. The remaining patients also showed some albopapuloid or hypertrophic scars at sites other than the leg, features seen in the albopapuloid or Cockayne-Touraine types. These were labeled as albopapuloid PEB or Cockayne-Touraine PEB. Common ancestry and various combinations of PEB, with albopapuloid or Cockayne-Touraine type of EB, were noted in some families. Compared with normal controls, the anchoring fibrils were rudimentary and sparser in both lesional and nonpredilected normal skin, although in the latter the changes were less marked in PEB than in the albopapuloid or Cockayne-Touraine types. Common ancestry may contribute to the higher incidence of DEB, especially PEB, in Tainan, Taiwan. The abnormalities of anchoring fibrils were not restricted to the predilected site in PEB and did not distinguish PEB from other types of DEB.