Transient bullous dermolysis of the newborn

A black male newborn developed large bullae on his extremities and other friction areas shortly after birth, which healed rapidly with hypopigmentation but no scarring. New lesions appeared occasionally for four months but ceased thereafter. At 12 months, the infant was healthy with some residual hypopigmentation. Histologic and electron microscopic examinations showed subepidermal bullae due to subbasal lamina separation, caused by collagenolysis and damage to anchoring fibrils. The lower epidermis keratinocytes had large, dilated rough endoplasmic reticulum (RER) containing electron-dense stellate bodies, suspected to be proteolytic enzymes responsible for collagenolysis. The severity of collagenolysis correlated with the number and size of RER vacuoles.