++
AT-A-GLANCE
Rare, autoimmune subepidermal bullous disease due to immunoglobulin G autoantibodies to Type VII collagen.
Etiology is unknown.
Skin fragility, subepidermal blisters, residual scarring, and milia formation. Common sites are trauma-prone areas such as hands, feet, elbows, knees, sacrum, nails, and mouth.
Related features may include an underlying systemic disease such as inflammatory bowel disease. May have erosions of the mucosa and esophageal stenosis.
Pathology shows subepidermal bulla, fibrosis, milia formation, and positive direct immunofluorescence for immunoglobulin G deposits at the epidermal–dermal junction.
Treatment options are limited and often difficult.
++
Epidermolysis bullosa acquisita (EBA) is a sporadic autoimmune bullous disease of unknown etiology. The disease has no gender, racial, ethnic, or geographical predisposition. There may be some genetic predisposition to EBA and autoimmunity in African Americans who live in the southeastern part of the United States.1 African American patients in the southeastern part of the United States who have either EBA or bullous systemic lupus erythematosus (SLE) have a high incidence of the HLA-DR2 phenotype. The calculated relative risk for EBA in HLA-DR2+ individuals is 13.1 in these patients. These results also suggest that EBA and bullous SLE are immunogenetically related and that the HLADR2 gene either is involved with autoimmunity to anchoring fibril collagen or is some sort of a marker for some other gene that exists in linkage disequilibrium with it.1
++
In another study examining HLA genotypes in EBA patients, it was found that HLA-DRB1*15:03 was overrepresented.2
++
In concordance with the genetic permissiveness towards EBA in humans, an active murine model of EBA in which mice are immunized with murine Type VII collagen, the development of EBA depends on the strain of mouse used.3,4
++
EBA is an exceedingly rare disease and considerably less frequent than other autoimmune bullous diseases (bullous pemphigoid, pemphigus vulgaris, dermatitis herpetiformis, etc.), which themselves are quite rare. In unselected bullous disease patients who exhibited an anti–basement membrane zone autoantibody in their blood, approximately 5% had the diagnosis of EBA or bullous SLE.5 This incidence is similar to those reported by other investigators.6 A prospective French study using electron and immune-electron microscopy to confirm the diagnosis of EBA, found an incidence rate as 0.17 to 0.26 per million people and accounted for only 2% to 3% of all patients with a subepidermal autoimmune bullous disease.7 The incidence of EBA in a region of Germany was 0.17, again confirming the rarity of EBA.8
+++
ETIOLOGY AND PATHOGENESIS
++
EBA is a chronic, subepidermal blistering disease associated with autoimmunity to the collagen (Type VII collagen) within anchoring fibril structures that are located at the dermal–epidermal junction (DEJ). Although the precise etiology of EBA is unknown, most of the evidence suggests an autoimmune etiology. The immunoglobulin G (IgG) autoantibodies to Type VII collagen are associated ...