EPIDERMOLYSIS BULLOSA (EB)
Epidermolysis Bullosa (EB) consists of a group of conditions that cause fragile skin. People with epidermolysis bullosa develop blisters or cuts from minor trauma. There are several subtypes of epidermolysis bullosa caused by different genetic mutations. The prognosis of an individual with epidermolysis bullosa varies based on disease subtype.
What causes epidermolysis bullosa?
Epidermolysis bullosa is caused by genetic mutations that cause problems in forming the necessary components of the basement membrane zone. The basement membrane zone is the attachment between the epidermis, the top layer of skin, and the dermis, the later just beneath the epidermis. The basement membrane zone of people with epidermolysis bullosa is not as strong as it should be, and therefore damage to the skin occurs more easily.
What are the subtypes of epidermolysis bullosa?
There are four main subtypes of epidermolysis bullosa:
1. Epidermolysis bullosa simplex (EBS) - This is the most common form of epidermolysis bullosa, accounting for 75-85% of cases (Abu Sa’d et al, 2006). It is typically inherited in an autosomal dominant fashion, meaning that it is passed from one parent to a child. Epidermolysis bullosa simplex can affect one area of the body or can cause widespread blistering and skin breakdown. Generally, the localized form of epidermolysis bullosa heals without scars, but the more widespread form can cause scarring.
2. Junctional epidermolysis bullosa (JEB) - This form of epidermolysis bullosa is inherited in an autosomal recessive fashion, meaning that each parent passes a gene for the disease. People with junctional epidermolysis bullosa have blistering of the skin and mucosal surfaces (mouth, genitals) that results in scarring. There are several subtypes of junctional epidermolysis bullosa, some of which are associated with other medical problems.
3. Dystrophic epidermolysis bullosa - This form of epidermolysis bullosa is caused by mutations in collagen type VII, which is an important part of the basement membrane zone in skin and other tissues. There are dominant and recessive forms of this condition. People with this condition can have fragile skin, blistering, and severe scarring. They can also have problems in the mucosal surfaces such as the mouth and the upper part of the esophagus. The recessive generalized form is the most severe and can lead to blistering that begins and birth and scarring that causes a “mitten” deformity of the hands and feet.
4. Kindler syndrome - This is an autosomal recessive form of epidermolysis bullosa that causes skin blisters, sensitivity to the sun, skin thinning, abnormal pigmentation, and prominent blood vessels.
What are the common complications of epidermolysis bullosa?
Malnutrition and anemia can be a serious problem for people with epidermolysis bullosa. These patients may have trouble eating and absorbing enough nutrients. The skin is also an important barrier that retains water and certain nutrients. The skin barrier in epidermolysis bullosa is disrupted, and therefore water and nutrients can be lost. Finally, people with epidermolysis bullosa are constantly devoting energy and nutrients to repairing damaged skin.
Skin infections occur commonly in people with epidermolysis bullosa. The skin is an important protective barrier against infection, and the disturbed barrier and open wounds in individuals with epidermolysis bullosa predisposes them to skin infections.
Individuals with epidermolysis bullosa may develop skin cancer, specifically squamous cell carcinoma, at an increased rate when compared to the normal population. The subtype of epidermolysis bullosa most likely to involve squamous cell carcinomas is the recessive dystrophic subtype. These squamous cell carcinomas tend to be more aggressive and deadly than the squamous cell carcinomas seen in the normal population.
Does epidermolysis bullosa affect tissues other than the skin?
Severe epidermolysis bullosa can have manifestations besides those seen in the skin. There can be chronic, non-healing, and scarring wounds. The most commonly affected sites are the hair, nails, eyes, mouth, gastrointestinal tract and genitourinary tract. The manifestations of epidermolysis bullosa on these areas can contribute meaningfully to the morbidity and mortality of the disease.
How is epidermolysis bullosa treated?
There is no specific therapy for epidermolysis bullosa currently, and each individual requires different treatments. The major aspects of disease management include supportive care and management of complications. One very important part of supportive care is management of the chronic wounds. This will promote healing and decrease the risk of infection. Infections can be prevented and treated using special creams, ointments, bathing solutions, bandages and wraps. Sometimes, more serious infections require antibiotics. Individuals with epidermolysis bullosa may need some nutritional support. Finally, epidermolysis bullosa can be painful, so pain management is an important aspect of care.