Intraepidermal Type VII Collagen by Immunofluorescence Mapping: A Specific Finding for Bullous Dermolysis of the Newborn

Background Bullous dermolysis of the newborn (BDN) is a subtype of dystrophic epidermolysis bullosa (DEB) characterized by skin fragility and blister formation at birth that typically resolves within the first year of life. Abnormal intraepidermal retention of type VII collagen (C7) has been reported as a characteristic feature of BDN, but few studies have investigated the specificity of this finding. Methods We retrospectively reviewed pathology reports of patients diagnosed with DEB using immunofluorescence mapping from January 2001 to January 2015. For cases describing intraepidermal accumulation of C7, we collected information on patient characteristics, including genetic testing results, clinical outcome, and concurrent electron microscopy findings, where available. Results Of the 143 cases of DEB with immunofluorescence mapping, eight patients had intracytoplasmic epidermal retention of C7. Of these eight patients, two were lost to follow‐up, four had complete resolution of bullae, and two had marked improvement with rare residual bullae. Concurrent electron microscopic findings available for three patients were consistent with BDN. Conclusions Our review of immunofluorescence mapping findings in patients with DEB found that 5.6% had abnormal intracytoplasmic epidermal retention of C7, a finding previously reported in BDN. All such patients with clinical outcomes available had resolution or marked improvement of bullae, consistent with clinical outcomes expected in BDN.