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What Is Epidermolysis Bullosa?

While most people can put up with an occasional blister from footwear, it's a bad gamble for a person with EB. See more pictures of skin problems.
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Skin is a pretty amazing organ. It's in a constant state of death and rebirth as new skin cells (called keratinocytes) are born and replace the dead cells that slough off. Before they're lost, dead skin cells serve as the barrier that protects the younger skin and internal organs beneath from exposure to the elements, radiation from the sun and infection from bacteria.

Human skin also has a defense system that goes to work when its integrity gets compromised by injuries from friction or heat. You see this system in action every time a blister forms on your skin.

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When skin is irritated by friction or exposure to high temperatures, the layers can loosen. When this occurs, the empty pocket between them is filled with a fluid called serum. This serum serves as a cushion that allows the immature, tender skin beneath to heal, a process called re-epithelialization. As it does, the injured outside layer deadens and falls off.

Blisters are a normal and beneficial reaction to damaged skin. For most of us, they pose little more than a nuisance. For people who suffer from a condition called epidermolysis bullosa, however, blisters can be life-threatening.

Epidermolysis bullosa (EB) is a disorder where inherited mutations on 10 genes lead to a heightened blister response in the sufferer's skin. People with EB have fragile skin; even mild heat and friction can create injuries and cause blisters. While blisters can be painful, consistent and prolonged blistering can also pose a risk to a person's health, as it increases the likelihood that a blister will become infected [source: NIAMS].

The condition is actually a set of varying conditions that are defined by how blisters form, but all EBs share a lack of a cure.

Next we'll look at different types of EB and how sufferers deal with their condition.

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.
©iStockphoto.com/whitemay

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.

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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?

Burn blisters can form on the skin of people with EB simply from changes in room temperature.
Burn blisters can form on the skin of people with EB simply from changes in room temperature.
©iStockphoto.com/mahlrovitz

It's easy to overlook blisters because most of us get them infrequently, but people who suffer from epidermolysis bullosa must deal with persistent blisters. This can be a challenge, especially since blisters formed from friction develop most commonly on the palms of the hands and soles of the feet, which can make the disorder debilitating. Room temperatures must be kept constant, infants can't be held easily and sufferers often wear mittens to bed to guard against accidental scratching while they sleep [source: NIAMS].

As you can imagine, the lifestyle of a family with a member who has EB is unusual. But while inconvenience can be surmounted, pain is another aspect of EB that must be addressed.

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If you've ever had a blister, you know it can be painful. But the sore was likely isolated to a single spot, like your heel after wearing a tight shoe. With EB, the painful bumps commonly form all over the body, leading to a great deal of pain for the sufferer. While there is no cure for EB, treatment is usually centered on pain management for the patient and preventing infection [source: NLM]. A doctor can diagnose the disorder and type through a skin biopsy and will generally prescribe painkillers. The patient and her family will also be versed in the art of applying bandages to keep blisters sterile and in recognizing infections that can lead to further complications.

The risk of infection is great in EB because of the high number of open sores on the body. Equally dangerous is blisters within the body. Blisters that form on the esophagus and trachea make it difficult to swallow and breathe. As a result of these symptoms, epidermolysis bullosa can be fatal. The junctional type, typically the only lethal type, has a mortality rate of 87 percent among infants [source: NLM].

Learning that your child has epidermolysis bullosa doesn't mean a negative prognosis, however. Most cases have no effect on life span; they just require that parents and patients be more aware of the skin the rest of us take for granted.

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Sources

  • Garner, WL, et al. "The effects of burn blister fluid on keratinocytes replication and the differentiation." Journal of Burn Care Rehabilitation. March/April 1993.http://www.ncbi.nlm.nih.gov/pubmed/8501098
  • Mayo Clinic. "Epidermolysis bullosa." September 26, 2009. http://www.mayoclinic.com/health/epidermolysis-bullosa/DS01015
  • National Institutes of Health. "Epidermolysis bullosa." National Institute of Arthritis and Musculoskeletal and Skin Diseases. September 2009. http://www.niams.nih.gov/Health_Info/Epidermolysis_Bullosa/epidermolysis_bullosa_ff.asp
  • National Institutes of Health. "Epidermolysis bullosa." MedlinePlus. October 31, 2008. http://www.nlm.nih.gov/medlineplus/ency/article/001457.htm

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