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Acquired epidermolysis bullosa
Epidermolysis bullosa acquisita (EBA) is a subepidermal bullous dermatosis of autoimmune origin that was named as a result of its resemblance to hereditary forms of epidermolysis bullosa (HEB), most notably dystrophic HEB.
- Epidermolysis bullosa acquisita
- Prevalence: Unknown
- Inheritance: Not applicable
- Age of onset: Adult
- ICD-10: L12.3
- OMIM: -
- UMLS: -
- MeSH: -
- GARD: 6360
- MedDRA: 10056508
The prevalence is unknown but the incidence is estimated at 1 in 96,200 new cases per year.
The disease manifests in two clinical forms: a classical form and an inflammatory form. In the classical form, onset occurs in adulthood and the bullae may be soft, tense or haemorrhagic, located on otherwise healthy skin. Lesions are usually triggered by minor trauma and are mainly localised to sites that are easily injured. Involvement of the mucous membranes, hair and nails is frequent. The inflammatory form was recognised more recently and resembles bullous pemphigoid (see this term) with bullae developing on erythematous skin lesions, plaques without bullous eruptions and diffuse lesions that are not limited to trauma-prone sites. The disease manifests during childhood. EBA is present in association with another disease (most notably Crohn's disease, haemorrhagic rectocolitis or diabetes mellitus) in 10-50% of cases. The nosological boundaries between EBA and bullous systemic lupus erythematosus (see this term) remain under debate.
EBA is caused by the production of antibodies against the skin basement membrane collagen VII, the major component of the anchoring fibrils located in the dermal-epidermal junction, under the lamina densa. As in dystrophic HEB caused by mutations in the gene encoding collagen VII, the deposition of antibodies on collagen VII leads to cleavage between the epidermis and dermis below the lamina densa.
Diagnosis relies on the results of histological analysis, indirect or direct immunofluorescence studies, immunoblotting and immune electron microscopy.
The differential diagnosis should include other subepidermal, autoimmune bullous diseases.
Management and treatment
The first line treatment revolves around administration of dapsone or sulfasalazine. Immunosuppresive therapy (such as treatment with cyclosporine) may by required in severe cases. Although further trials are necessary, encouraging results have been obtained with other approaches such as intravenous immunoglobulin therapy, extracorporeal photochemotherapy and, more recently, rituximab therapy.
EBA is a chronic disease that resolves slowly and leads to dystrophic scarring and milia. During the disease course, the inflammatory forms may evolve to resemble the classical form and patients with the classical present with bursts of inflammatory disease. Involvement of the mucosae (in particular the ocular and ORL mucosal membranes) is associated with more severe disease, which may lead to a poorer functional, or even vital, prognosis.
- Clinical practice guidelines
- Français (2011, pdf)