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What is epidermolysis bullosa?


Types of Epidermolysis Bullosa
EB can arise either from malfunctioning genes that govern the expression of proteins related to skin development or can be acquired by an immune deficiency.
EB can arise either from malfunctioning genes that govern the expression of proteins related to skin development or can be acquired by an immune deficiency.
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There are three types of inherited epidermolysis bullosa, and a fourth extremely rare disorder that people may acquire later in life. This fourth type, EB acquisita, usually appears after age 50 and is an autoimmune disorder, where the body's immune system mistakes skin cells and structural fibers for foreign bodies and attacks them [source: NLM]. The disease affects up to 1 in 30,000 people.

The inherited types of EB -- simplex, junctional and dystrophic -- are differentiated based on the gene mutations that cause the skin abnormalities that lead to blisters. However, all three types originate in the basement membrane, the area where the outer epidermis layer of skin connects to the dermis beneath. Depending on the gene mutation, a variety of problems in the connection between these two areas can occur.

In junctional EB, the gene mutation has led to the underproduction of proteins that produce fibers called hemidesmosomes that anchor the epidermis to the basement layer. In dystrophic EB, less collagen is under produced due to gene mutation, causing a light or nonexistent connection between the epidermis and the dermis [source: Mayo Clinic].

In EB simplex, the most common form of the disorder, the genes that oversee the production of keratin -- a protein that provides structure and toughness to skin -- don't signal enough to be produced. Keratin is also vital in the formation of other parts of the body, like fingernails and tooth enamel. As a result of low keratin production, people with EB simplex often have problems with their teeth and disfigured fingernails and toenails, as well as hair loss from fine and thinning hair.

Because the connection in the basement membrane is structurally unsound, the skin of an EB sufferer gets injured easily, which leads to the characteristic blisters. Not all of these appear on the skin; the lining of the esophagus, stomach, throat and bladder can also form blisters, leading to further health risks.

Most forms of EB present themselves in infancy. In the most extreme cases, a baby may be born with blisters on its skin [source: Mayo Clinic]. A common avenue to diagnosis of the condition is the appearance of inexplicable blisters on an infant's body. In other cases, blisters begin to form once a child becomes more active. Even the friction created by walking, crawling and playing can lead to blisters.

There isn't a cure for epidermolysis bullosa. So how do patients and families cope with EB?


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