Epidermolysis bullosa acquisita (EBA) is a rare, chronic, acquired autoimmune blistering disease of the skin and mucous membranes. Characterized clinically by the development of subepidermal tense vesicles and bullae, EBA typically occurs in adults, although it can occur in individuals of any age. Fewer than 100 pediatric cases have been reported in the literature. Patients demonstrate autoantibodies directed against type VII collagen, a major component of the skin's basement membrane.

There are several clinical forms of EBA, as defined by the International Bullous Diseases Group in 2018:

• Classical / mechanobullous form – A noninflammatory form that affects trauma-prone sites and extensor skin surfaces.
• Nonclassical / nonmechanobullous bullous pemphigoid (BP)-like form – An inflammatory form with features characteristic of BP mixed with atypical lesions for BP, such as skin fragility and milia. It is characterized by a generalized eruption of vesicles and bullae.
• Mucous membrane form – A mucous membrane pemphigoid-like form, which predominantly affects mucous membranes (mouth, pharynx, conjunctiva, genitalia).
• Brunsting-Perry form – A chronic recurrent blistering dermatosis of the head and neck that presents with scarring alopecia.
• IgA form – A presentation that may resemble linear IgA bullous dermatosis and presents with linear IgA deposits in the basement membrane.

The linear IgA, mucosal predominant, and inflammatory subtypes are represented with greater frequency in the pediatric population.

EBA can also occur in different clinical settings; there are reports of EBA occurring as a paraneoplastic phenomenon, in association with psoriasis vulgaris, and in the setting of inflammatory bowel disease or other autoimmune diseases, particularly systemic lupus erythematosus (SLE). A meta-analysis estimated the prevalence of associated comorbidities at close to 10%. The same study found incidence of inflammatory bowel disease in 1.5% of patients with EBA. It is postulated that the damaged gut epithelium exposes previously sequestered collagen VII to the immune system, resulting in the generation of auto-antibodies, which escape and go on to attack the skin.

Associations with endocrinopathies and other systemic complications do not seem to follow the same rate in pediatric cases. The few pediatric cases that have associated autoinflammation were also found to have HLA-DR2 (most frequently), HLA-DR4, HLA-DR5, or HLA-DR7 aberrancy.

An increased incidence of EBA in patients with darker skin phototypes has previously been noted. This has now been attributed to enriched representation of HLA-DRB1*15:03 allele found in African Americans as well as HLADRB1*16.

EBA typically has a slow onset and a chronic clinical course. Scarring may produce secondary dysfunction, particularly of the hands and fingers, in the mechanobullous variant. Other sequelae include hair and nail loss, esophageal stenosis, periodontal disease, malnutrition, and blindness.

Related topic: epidermolysis bullosa simplex