Epidermolysis bullosa acquisita (EBA) is a rare autoimmune disease characterized by sub-epithelial blistering of the skin and mucosal membranes in response to injury. This mostly occurs in the hands, feet, knees, elbows, buttocks, mouth, nose, and eyes. It usually emerges in adulthood, mostly when people are in their 40s or 50s.
Causes of EBA
EBA is caused by autoantibodies that are generated in the patient’s body against a protein called type VII collagen. This is a major structural protein that connects the basement membrane of the epidermis (the top layer of the skin) with the extracellular matrix of the dermal layer underneath. The attack of the immune system on type VII collagen leads to the loss of anchoring between those two layers and results in the formation of blisters in response to injury.
EBA is not a genetic disease. It occurs sporadically in people with no previous family history of the disease and the cause is not known. However, EBA appears to be more common in people affected by other diseases, including Crohn’s disease, systemic lupus erythematosus, amyloidosis, myeloma, lung cancer, and lymphoma.
Types and symptoms of EBA
EBA is classified broadly into non-inflammatory (classical or mechano-bullous) and inflammatory types.
Non-inflammatory EBA makes up about one-third of all EBA cases. It is characterized by skin fragility, tense vesicles, and blisters on the extensor skin surface (skin surface on the outside of a joint) of hands, knees, knuckles, elbows, and ankles. The mucous membrane blisters rupture easily and lesions heal with significant scarring and milia (small white spots).
Inflammatory EBA accounts for nearly two-thirds of all EBA cases. Patients with inflammatory EBA show widespread eruptions involving the trunk, central body, extremities, and skin folds. In inflammatory EBA, blisters appear in both trauma-prone and non-trauma prone areas.
Clinically, inflammatory EBA mimics other autoimmune bullous dermatoses (AIBDs) such as bullous pemphigoid (BP), linear IgA dermatosis (LAD), mucous membrane pemphigoid (MMP), or Brunsting-Perry pemphigoid. Patients may have symptoms of one or more different subtypes of inflammatory EBA
BP-like inflammatory EBA
Patients with BP-like inflammatory EBA have widespread tense vesicles and blisters that are not restricted to trauma-prone regions. This subtype affects the trunk region and skin folds and is accompanied by generalized redness, itching, and plaque formation. It heals with minimal scarring and milia.
Linear IgA disease-like inflammatory EBA
This subtype is characterized by linear deposits of IgA (a type of antibody) in the basement membrane, and mucosal scarring.
Brunsting-Perry pemphigoid-like inflammatory EBA
This subtype is confined to the head and neck just like Brunsting-Perry type mucous membrane pemphigoid disease.
Mucous membrane pemphigoid (MMP)-like inflammatory EBA
This subtype affects mucous membranes of the buccal cavity, palate, conjunctiva, nasopharynx, esophagus, anus and the genitals. It can result in significant mucosal scarring and dysfunction.
The primary aim of EBA treatment is to protect the skin by preventing blisters from forming, promoting healing, and avoiding complications.
Since EBA is considered an autoimmune disease, it is mostly treated with immunosuppressive agents that decrease the production of the autoantibodies and alleviate disease symptoms.
Other medications that can be used to treat EBA include oral corticosteroids such as prednisone, or anti-inflammatory agents such as dapsone, colchicine, azathioprine, cyclophosphamide, mycophenolate, or intravenous immunoglobulin.
When patients do not respond to other therapies, they may be treated with rituximab.
Last updated: Feb. 17, 2020
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