Type VII Collagen Disorders Simplified.

Abstract

Epidermolysis bullosa acquisita (EBA) and bullous systemic lupus erythematosus (BSLE) are autoimmune mechanobullous diseases that are caused by autoantibodies directed against type VII collagen. The functionality of type VII collagen is vital to the skin and mucous membranes because it makes up the anchoring fibrils that adhere the epithelium to the underlying connective tissue. Dystrophic epidermolysis bullosa (DEB), which bears some clinical similarities to EBA and BSLE, is caused by mutations in the type VII collagen gene (COL7A1) that may be dominant or recessive, leading to partial or total loss of the anchoring fibrils. Differentiating all 3 of these rare diagnoses variably requires thorough personal and family histories, histopathology, immunopathology, autoantibody profile, electron microscopy, and gene mutation analysis. Treatment of EBA and BSLE involves antineutrophil and immunosuppressive drugs that often give unsatisfactory responses. Rituximab has been successful in resistant cases. Until recently, the treatment of DEB and other heritable epidermolysis bullosa (EB) diseases caused by disparate mutations was limited to supportive care, prevention of trauma to skin and wound infections, regular dressing changes, and skin cancer surveillance. Three major treatment advances recently were approved for DEB and junctional EB.