Epidermolysis bullosa acquisita (EBA) is a rare autoimmune disorder that causes the skin to blister in response to minor injury. Common areas of blistering include the hands, feet, knees, elbows, and buttocks. It can also affect the mouth, nose, and eyes. Some affected people have other health problems such as Crohn's disease, systemic lupus erythematosus, amyloidosis, or multiple myeloma. EBA is not inherited and usually occurs in adulthood. Treatment aims to protect the skin, stop the formation of blisters, and promote healing. Immunosuppressive drugs may be used to reduce the body's autoimmune response.

The underlying cause of epidermolysis bullosa acquisita (EBA) is not known. It is thought to be an autoimmune disorder, which means that the immune system attacks healthy cells by mistake. In EBA, certain immune proteins (usually IgG autoantibodies) mistakenly target and attack a specific type of collagen (a skin protein) involved in "anchoring" the skin. In some milder cases of EBA, the immune proteins involved are thought to be IgA, rather than IgG autoantibodies. The initiating event that leads to autoantibody production is unknown. EBA affecting several family members has been reported, suggesting a genetic component may be involved in some cases. Rarely, people with lupus, a systemic autoimmune disease, develop a generalized blistering skin disease with the features of EBA. EBA has also been associated with Crohn's disease.

Symptoms of epidermolysis bullosa acquisita (EBA) usually occur in a person's 30s or 40s. The signs and symptoms can differ among affected people, and the condition has several distinct forms of onset. For example:

Non-inflammatory or mildly inflammatory EBA affecting only trauma-prone skin (the "classic" form) may cause:

• tense, blood- or pus-filled blisters, mostly on the hands, knees, knuckles, elbows and ankles
• mucous-membrane blisters that rupture easily
• healing with significant scarring and small white spots (milia)

Generalized inflammatory EBA may cause:

• widespread blisters that are not localized to trauma-prone sites
• generalized redness and itching
• healing with minimal scarring

• blisters on various mucous membranes
• significant scarring and dysfunction

The features of the condition may change during the course of the disease or may represent two forms at the same time.

Unlike the genetic forms of epidermolysis bullosa, epidermolysis bullosa acquisita (EBA) is considered an acquired, sporadic disease. This means that it generally occurs in people with no history of the condition in their families. There have been a couple of reports of families with more than one affected person, suggesting a genetic component may be involved. This could mean that EBA may develop in a person who is "genetically susceptible." However, the condition is not thought to be due to any specific gene(s).