Epidermolysis bullosa (EB) is the name for a skin condition that causes blisters. The skin is so fragile in people with epidermolysis bullosa that even minor rubbing may cause blistering.
The blistering can lead to serious complications, including skin infection, and blisters in the mouth or may interfere with proper nutrition.
Milder cases of EB may become apparent when a child crawls, walks, or runs, or when a young adult engages in vigorous physical activity. In severe cases, blisters may develop inside the body, such as the inside of the mouth (mucosa), esophagus, stomach, upper airway, bladder, and urethra.
A person with epidermolysis bullosa may have normal appearing skin at birth but start to develop symptoms later in life. At times, a person with epidermolysis bullosa may not be aware of rubbing or injuring the skin even though blisters develop.
The skin has an outer layer called the epidermis and an underlying layer called the dermis. The place where the two layers meet is called the basement membrane zone. Epidermolysis bullosa is the result of changes to this part of the skin.
Types of Epidermolysis Bullosa
The main forms of epidermolysis bullosa are:
- Epidermolysis bullosa simplex. This type of EB is the result of a problem with the keratin, a protein in the epidermis.
- Junctional EB. This type of EB is the result of problem with how the epidermis is attached to the dermis. The defect leads to tissue separation and blistering in the upper part of the basement membrane.
- Dystrophic EB. The abnormality affects the basement membrane. In this condition, the filaments that anchor the epidermis to the underlying dermis are either absent or do not function. This is caused by defects in the gene for type VII collagen, a fibrous protein that is the main component of the anchoring filaments.
- Epidermolysis bullosa acquisita (EBA) is a rare autoimmune disorder in which the body attacks its own anchoring fibrils with antibodies, the special proteins that help fight and destroy foreign substances that invade the body. In most cases, the cause is unknown.
Each of these major types of epidermolysis bullosa have many subtypes.
Causes of Epidermolysis Bullosa
Epidermolysis is an inherited skin disorder that results from changes to the genes the person received from one or both parents.
More than 10 genes are known to underlie the different forms of EB.
Epidermolysis Bullosa Diagnosis
A skin biopsy is often necessary to diagnose epidermolysis bullosa and determine the type of EB that is causing blisters.
Genetic testing now makes it possible to identify specific genes in EB patients and their family members.
Prenatal diagnosis can now be accomplished by amniocentesis (removing and examining a small amount of amniotic fluid surrounding the fetus in the womb of a pregnant woman) or sampling the chorionic villus (part of the outer membrane surrounding the fetus) as early as the 10th week of pregnancy.
Symptoms of Epidermolysis Bullosa
Following is a summary of some of the characteristic signs of various forms of EB.
EB simplex (EBS). A generalized form of EBS usually begins with blistering that is evident at birth or shortly afterward. In a localized, mild form called Weber-Cockayne, blisters rarely extend beyond the feet and hands. Other signs may include thickened skin on the palms of the hands and soles of the feet; rough, thickened, or absent fingernails or toenails; and blistering of the soft tissues inside the mouth.
Junctional EB (JEB). This disease is usually severe. In the most serious forms, large, ulcerated blisters on the face, trunk, and legs can be life-threatening because of complicated infections and loss of body fluid that leads to severe dehydration. Survival is also threatened by blisters that affect the esophagus, upper airway, stomach, intestines, and urogenital system. Other signs found in both severe and mild forms of JEB include rough and thickened or absent fingernails and toenails; a thin appearance to the skin (called atrophic scarring); blisters on the scalp or loss of hair with scarring (scarring alopecia); malnutrition and anemia; growth retardation; involvement of soft tissue inside the mouth and nose; and poorly formed tooth enamel.
Dystrophic EB (DEB). The dominant and recessive inherited forms of DEB have slightly different symptoms. In some dominant and mild recessive forms, blisters may appear only on the hands, feet, elbows, and knees; nails usually are shaped differently; milia may appear on the skin of the trunk and limbs; and there may be involvement of the soft tissues, especially the esophagus. The more severe recessive form is characterized by blisters over large body surfaces, loss of nails or rough or thick nails, atrophic scarring, milia, itching, anemia, and growth retardation. Severe forms of recessive DEB also may lead to severe eye inflammation with erosion of the cornea (clear covering over the front of the eye), early loss of teeth because of tooth decay, and blistering and scarring inside the mouth and gastrointestinal tract. In most people with this form of EB, some or all the fingers or toes may fuse (pseudosyndactyly). Also, individuals with recessive DEB have a high risk of developing a form of skin cancer called squamous cell carcinoma. It primarily occurs on the hands and feet. The cancer may begin as early as the teenage years. It tends to grow and spread faster in people with EB than in those without the disease.
Epidermolysis Bullosa Treatment
People with mild forms of EB may not require extensive treatment. However, they should attempt to keep blisters from forming and prevent infection when blisters occur.
People with moderate and severe forms may have many complications and require psychological support along with attention to the care and protection of the skin and soft tissues.
In many forms of EB, blisters will form with the slightest pressure or friction. This may make parents hesitant to pick up and cuddle young babies. However, a baby needs to feel a gentle human touch and affection, and can be picked up when placed on a soft material and supported under the buttocks (bottom) and behind the neck. A baby with EB should never be picked up under the arms.
A number of things can be done to protect the skin from injury. These include:
- Avoiding overheating by keeping rooms at an even temperature.
- Applying moisturizers to the skin to reduce friction and keep the skin moist.
- Using simple, soft clothing that requires minimal handling when dressing a child.
- Using sheepskin on car seats and other hard surfaces.
- Wearing mittens at bedtime to help prevent scratching.
Caring for Blistered Skin
When blisters appear, the objectives of care are to reduce pain or discomfort, prevent excessive loss of body fluid, promote healing, and prevent infection.
The doctor may prescribe a mild analgesic to prevent discomfort during changes of dressings (bandages). Dressings that are sticking to the skin may be removed by soaking them off in warm water. Although daily cleansing may include a bath with mild soaps, it may be more comfortable to bathe in stages where small areas are cleaned at a time.
Blisters can become quite large and create a large wound when they break. Therefore, a medical professional will likely provide instructions on how to safely break a blister in its early stages while still leaving the top skin intact to cover the underlying reddened area.
A moderately moist environment promotes healing, but heavy drainage from blister areas may further irritate the skin, and an absorbent or foam dressing may be needed. The doctor or other health care professional may recommend gauze or bandages that are soaked with petroleum jelly, glycerin, or lubricating substances, or may suggest more extensive wound care bandages or products.
The chances of skin infection can be reduced by good nutrition, which builds the body’s defenses and promotes healing, and by careful skin care with clean hands and use of sterile materials. For added protection, the doctor may recommend antibiotic ointments and soaks.
Even in the presence of good care, it is possible for infection to develop. Signs of infection are redness and heat around an open area of skin, pus or a yellow drainage, excessive crusting on the wound surface, a red line or streak under the skin that spreads away from the blistered area, a wound that does not heal, and/or fever or chills. The doctor may prescribe a specific soaking solution, an antibiotic ointment, or an oral antibiotic to reduce the growth of bacteria.
Wounds that are not healing may be treated by a special wound covering or biologically developed skin.
Treating Nutritional Problems
Blisters that form in the mouth and esophagus in some people with epidermolysis bullosa are likely to cause difficulty in chewing and swallowing food and drinks. If breastfeeding or bottle-feeding results in blisters, infants may be fed using a preemie nipple (a soft nipple with large holes), a cleft palate nipple, an eyedropper, or a syringe. When the baby is old enough to take in food, adding extra liquid to pureed (finely mashed) food makes it easier to swallow. Soups, milk drinks, mashed potatoes, custards, and puddings can be given to young children. However, food should never be served too hot.
Dietitians can identify high-caloric and protein-fortified foods and beverages that help replace protein lost in the fluid from draining blisters. They can suggest vitamin and mineral nutritional supplements that may be needed, and show how to mix these into the food and drinks of young children. Dietitians can also recommend adjustments in the diet to prevent gastrointestinal problems, such as constipation, diarrhea, or painful elimination.
Surgical treatment may be necessary in some forms of epidermolysis bullosa. Individuals with the severe forms of autosomal recessive dystrophic EB whose esophagus has been narrowed by scarring may require dilation of their esophagus for food to travel from the mouth to the stomach. Other individuals who are not getting proper nutrition may need a feeding tube that permits delivery of food directly to the stomach. Also, patients whose fingers or toes are fused together may require surgery to release them.
Photo courtesy of Master Sgt. Keith A. Milks of the U.S. Marine Corps