Chapter 42: Epidermolysis Bullosa Acquisita

EPIDERMOLYSIS BULLOSA ACQUISITA

Therapeutic Approach

Epidermolysis bullosa acquisita (EBA) is an autoimmune blistering disease of the skin, which is a chronic incurable disorder requiring modulation of the patient’s immune system and skin inflammation.^1,2 EBA is due to IgG or IgA autoantibodies that are inappropriately generated by the patient’s immune system against a normal skin protein, type VII collagen.^3,4 This collagen is located at the basement membrane zone of the dermal-epidermal junction and is conformed into very large structures call anchoring fibrils. Anchoring fibrils are necessary for the two main layers of skin—the epidermis and dermis—to adhere properly to one another. Without anchoring fibrils, the epidermis poorly adheres to the dermis and the patient experiences skin fragility, skin blistering and open erosive wounds that heal with scarring and with tiny epidermal cysts called milia.⁴ There are four main forms of EBA: (1) the classic mechano-bullous form that is relatively noninflammatory and occurs predominantly in areas of trauma,^1,2 (2) the bullous-pemphigoid-like form of EBA that is reminiscent of pemphigoid with tense bullae on inflammatory bases,^5,6 (3) mucosal-predominant EBA that has lesions predominantly on mucosal surfaces such as the mouth, eyes, and anal area and is categorized as one type of mucous membrane pemphigoid,⁷ and (4) a presentation that has been misnamed as Brunsting-Perry pemphigoid with scarring lesions on the face and neck and some mucosal lesions.^7,8 EBA is a very rare disease (0.25 cases per million).^9-11 Therefore, there have been no double blinded controlled clinical trials. The basis for treatment outlined in the table below rests solely upon anecdotal reports and uncontrolled small case series. In the authors’ experiences, systemic steroids are usually minimally effective for the mechano-bullous form of EBA but may be helpful in the bullous-pemphigoid-like form of EBA. Oral colchicine at doses over 2 mg per day is a benign treatment with few side effects and is often helpful in all forms of EBA. Rituximab infusions are also often helpful in all forms of EBA.

Levels of evidence are based on the Journal of the American Academy of Dermatology guidelines: Level IA evidence includes evidence from meta-analysis of randomized controlled trials; level IB evidence includes evidence from ≥1 randomized controlled trial; level IIA evidence includes evidence from ≥1 controlled study without randomization; level IIB evidence includes evidence from ≥1 other type of experimental study; level III evidence includes evidence from nonexperimental descriptive studies, such as comparative studies, correlation studies, and case control studies; and level IV evidence includes evidence from expert committee reports or opinions or clinical experience of respected authorities, or both. See Table 42-1.