What Is Epidermolysis Bullosa? What Causes Epidermolysis Bullosa?

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Main Category: Dermatology
Also Included In: Pediatrics / Children's Health
Article Date: 10 Nov 2009 - 0:00 PST

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Epidermolysis bullosa (EB) is a group of rare genetic skin conditions that cause the skin to blister in response to minor injury, heat, or friction from rubbing or scratching. Genetic conditions are inherited. They are caused by faulty genes that run in the family.

Most types of epidermolysis bullosa initially affect infants and young children. Some people with mild forms of the condition do not develop signs and symptoms until adolescence or early adulthood. Mild forms of EB may improve with age, but severe forms may cause serious complications and can be fatal. Some infants are born with blisters. Children with EB are sometimes called butterfly children because their skin is said to be as fragile as a butterfly's wing.

EB affects boys and girls equally, and can affect any ethnic group. In rare cases, EB can also affect adults, but the condition tends to be mild.

There is no cure for EB. Treatment depends on the severity, but it is often aimed at preventing pain, infection and other complications.

There are three main types of EB:

• Epidermolysis Bullosa simplex. This is the most common type of EB, 70 percent of EB cases.
• Dystrophic Epidermolysis Bullosa affects about 25 percent of people with EB.
• Junctional Epidermolysis Bullosa affects about 5 percent of people with EB.

Within each type of EB, there are several different forms and symptoms and causes can vary. Currently, there are more than 25 known forms of EB.

If a child has EB, faulty genes in their skin cells cause blisters to form. Their skin is also very fragile. Even the slightest rubbing, friction or minor injury can cause their skin to blister and tear.

Blisters can also develop on their own, even if the skin is not damaged. Blisters and skin damage can leave open wounds and raw patches on the skin.

Some forms of EB can make everyday activities, such as learning to crawl and walk, difficult for both babies and older children.

According to Medilexicon's medical dictionary, Epidermolysis bullosa is:

"a group of inherited chronic noninflammatory skin diseases in which large bullae and erosions result from slight mechanical trauma; a form localized to the hands and feet is called Weber-Cockayne syndrome, of autosomal dominant inheritance caused by mutation in either the gene encoding keratin-5 (KRT5) on chromosome 12q or the gene for keratin-14 (KRT14) on 17q."

Mild or severe forms of EB

Some forms of EB can be mild. Symptoms may affect only localized parts of the body, such as the feet and hands. The symptoms of some forms can also improve as a child grows older.

In other forms of EB, blisters and skin damage can be more widespread. Blisters may form in the mouth, eyes, nose, stomach, airways and genitals.

Some forms of EB can be severe, and the condition can be life threatening.

EB acquisita.

A rare skin condition that mainly affects adults. EB acquisita also causes blistering. However, EB acquisita is not a genetic disease; it is an autoimmune condition. The immune system produces antibodies, which normally attack foreign cells such as bacteria. In an autoimmune condition, the antibodies attack the body's own healthy cells and tissue. In EB acquisita, antibodies attack and destroy skin cells, causing blisters to form. It is sometimes linked with other conditions such as Crohn's disease, diabetes, systemic lupus erythematosus which is an inflammation of tissues affecting the whole body.

What are the signs and symptoms of epidermolysis bullosa?

A symptom is something the patient feels and reports, while a sign is something other people, such as the doctor notice. For example, pain may be a symptom while a rash may be a sign.

The primary indication of epidermolysis bullosa is the eruption of fluid-filled blisters (bullae) on the skin. They most commonly appear on the hands and feet in response to friction. In mild cases, blisters heal without scarring.

The symptoms of EB usually develop in babies. They can be present at birth or develop soon after. Symptoms tend to develop later in life with milder forms of EB, for example, when the condition affects adults. EB in adults is rare. Signs and symptoms of epidermolysis bullosa may include:

• Blisters forming in the skin
• Deformity or loss of fingernails and toenails
• Dental abnormalities, such as tooth decay from poorly formed tooth enamel
• Difficulty swallowing
• Excessive sweating
• Internal blistering, including on the throat, esophagus, upper airway, stomach, intestines and urinary tract
• Peeling of the skin
• Scalp blistering, scarring and hair loss
• Skin falling off
• Skin thickening on palms and soles of the feet (hyperkeratosis)
• Tearing of the skin
• Thin-appearing skin
• Tiny white skin bumps or pimples (milia)

In EB, the skin is fragile and can easily be damaged by:

• the slightest rubbing or friction
• minor injuries, including knocks and bumps
• clothing that touches or rubs the skin

In some forms of EB, blisters can affect the eyes and the body's internal linings, such as the membranes inside the mouth, nose, airways, esophagus, stomach and genitals.

Seek prompt medical attention if a baby or child develops blisters, and there is no apparent reason for them. In some cases of epidermolysis bullosa, blistering may not appear until a toddler first begins to walk, or until an older child begins new physical activities that trigger more intense friction on the feet.

If a child has been diagnosed with epidermolysis bullosa and develops signs of an infection around an open area of skin, seek medical attention. Such signs can include:

• Redness, heat or pain
• Pus or a yellow discharge
• Crusting
• Red line or streak under the skin, stretching away from the wound
• A wound that does not heal
• Fever or chills

Blisters can lead to infection and deformity. Proper care is essential.

Seek medical attention for individuals of all ages experiencing problems swallowing or breathing.

There are different types of EB. The main types of EB include:

• EB simplex
• dystrophic EB
• junctional EB
• Kindler syndrome

Within these types, there are different forms of EB, and the symptoms can range from mild to severe.

EB simplex (localized and generalized)

This most common and generally mildest form usually begins at birth or in early infancy. The faulty genes are involved in the production of keratin. If one parent has the single faulty gene, there is a 50 percent chance his or her offspring will have the defect.

Blisters develop mainly on a child's hands (on the palms) and feet (on the soles). Symptoms may include excessive sweating on the hands and feet (hyperhidrosis). This form of EB is called localized EB simplex, or Weber-Cockayne EB simplex.

There may also be blisters inside the mouth. This form of EB is called generalized EB simplex, or Köbner (or Koebner) EB simplex.

In these forms of EB simplex, the blisters usually heal without leaving scars. Warm weather, heat and humidity can make the blistering worse.

EB simplex (Dowling Meara)

The Dowling Meara form of EB simplex is more severe. The blisters appear in clusters. Blistering or skin loss may be widespread.

The baby may have blisters on their voice box (larynx), which can cause a hoarse cry. Also, they may have blisters in their mouth, which can cause feeding problems. In this type of EB simplex, the blistering often improves as the child gets older. After blisters heal, they may leave the skin discolored.

Dystrophic EB (DEB)

The symptoms of DEB can vary widely. They can be mild to severe. In some forms of DEB, blisters may only affect part of the body (localized) or can be much more widespread (generalized). After the blisters heal, they usually leave scars and small, raised white spots on the skin.

If DEB is inherited from one parent (dominant inheritance), the symptoms are usually milder. This form is called dominant dystrophic EB (DDEB).

If DEB is inherited from both parents (recessive inheritance), the condition tends to be more severe. This form is called recessive dystrophic EB (RDEB). The symptoms can be very severe. There can be extensive blistering and scarring, as well as problems with the digestive system and the kidneys. This form is called severe generalized RDEB, or Hallopeau-Siemens RDEB.

Junctional EB (JEB)

The disorder generally begins at birth. As with DEB, the symptoms of JEB can vary and can be mild or severe. Blisters and fragile skin can affect only part of the body, or they can be very widespread.

Herlitz JEB is a severe, life-threatening form of the condition. Herlitz JEB causes many complications, including extensive loss of skin, breathing difficulties and anemia (iron deficiency).

Kindler syndrome

In Kindler syndrome, blistering mainly affects the hands and feet. Other symptoms that can also affect the skin are gradual wasting away (atrophy), sensitivity to light (photosensitivity) and skin color or pigment variation (poikiloderma).

What are the causes of Epidermolysis bullosa?

In most cases, epidermolysis bullosa is inherited. It is caused by faulty genes in skin cells. These genes control the way the body produces skin. It is also possible to develop EB as a result of a random mutation in a gene.

Blisters

The skin is made up of different layers including the top layer (epidermis) and the lower layers (dermis).

Because of the faulty genes the different skin layers cannot hold or stick together, and they separate. Where the layers of skin have separated, fluid gathers in the space to form a blister. The skin is fragile and easily damaged.

Currently, there are more than 25 known forms of EB and three main types. Each type is caused by different genes and different faults. Researchers have identified the genetic mutations that cause most forms of EB.

Where and when blisters develop depends on the type of epidermolysis bullosa. The faulty genes cause blisters to form in different layers of the skin, depending on the type of EB. For example:

• In dystrophic EB: blisters form in the lower layers and tissues of the skin.
• In EB simplex: blisters form within the top layer of the skin (epidermis).
• In junctional EB: blisters form where the top and lower layers meet.
• In Kindler syndrome: the layers of skin where blisters form can vary.

In some forms of EB, the faulty genes can also cause blisters to form inside the body, inside the mouth, nose, esophagus, stomach, airways and genitals.

Genetic conditions

All human beings inherit two genes for each characteristic (eye color, height and skin color). One gene comes from each parent.

A child can inherit a genetic condition in several ways. For example:

• Dominant inheritance: One parent can pass on a faulty gene to their child. In this case, the parent will also have the condition.
• Recessive inheritance: Both parents pass on faulty genes to the child. In these cases, the parents will not have the condition, and may not be aware that they are carriers.

How is EB inherited?

EB can be inherited in different ways. The forms inherited from both parents (recessive) tend to be more severe.

EB simplex is usually inherited from one parent who has the faulty gene. The parent also has the condition.

In rare cases, a child can have EB simplex where there is no family history of the condition. A gene can mutate, even though neither parent has the condition. What causes the genes to mutate is unknown.

Dystrophic EB can be inherited from both parents, or from one parent. Junctional EB and Kindler syndrome are inherited from both parents. Junctional epidermolysis bullosa is the result of both parents carrying and passing on the defective gene, although neither parent may clinically have the disorder (silent mutation). If both parents have the faulty gene, there is a 25 percent chance that one of their offspring will have the defect and develop the disorder.

What are the risk factors of epidermolysis bullosa?

A risk factor is something which increases the likelihood of developing a condition or disease. For example, obesity significantly raises the risk of developing diabetes type 2. Therefore, obesity is a risk factor for diabetes type 2.

The major risk factor for developing the disorder is to have a family history of epidermolysis bullosa.

How is epidermolysis bullosa diagnosed?

During medical evaluation the skin will be examined to assess:

• size of the blisters
• how easily the skin is damaged
• how much of the body is affected
• what causes the blisters
• where the blisters are on the body

The mouth, eyes, nails, teeth, and hair will be examined. There will be a review of the parents' family history of EB.

Testing is necessary to confirm diagnosis of EB and to identify the type of EB and how it was inherited.

A biopsy may be carried out, where a sample of the skin tissue is taken for testing. In some cases, blood samples may be taken from the child and their parents. The samples can be used for genetic tests in order to confirm whether the condition has been inherited from one or both parents.
 


After the diagnosis

If a child is diagnosed with EB, they will be referred to a specialist EB centre.

What is the treatment for epidermolysis bullosa?

There is currently no cure for epidermolysis bullosa (EB). Treatment of EB aims mainly at preventing complications, easing discomfort from blistering and controlling the condition's symptoms.

Skin care


Blisters may be large. Once broken, they are susceptible to infection and fluid loss. They may be punctured with a sterile needle. Leaving the roof of the blister intact allows for drainage of the blister while protecting the underlying skin. Antibiotic ointment, petroleum jelly or other moisturizing substance may be recommended before applying a non-sticking bandage. In some cases, there may be no need for a dressing and it is best to 'dust' the blister with corn flour, which helps to dry it and reduce further friction.

In the case of wounds that do not heal over time, skin grafts may be recommended, using either the parents' or the child's own skin, or manufactured skin. Covering the wound with skin can help stimulate healing.

Surgery


Repeated blistering and scarring can cause deformities. Surgery may be recommended to correct these deformities, particularly if they interfere with normal activity.

Blistering and scarring of the esophagus may lead to esophageal narrowing, making eating difficult. Surgery to widen the esophagus may be needed. Using light sedation, a small balloon is inflated in the esophagus to dilate the area.

If feeding is impossible, a tube may be implanted to deliver food directly to the stomach.

Physical therapy


It can help ease the limitations on motion caused by scarring and contracture.

Specialist centers for EB

Children with EB can have complex needs, particularly if they have a severe form of EB. Their care may involve many different healthcare professionals. Specialist centers coordinate care for children and adults with EB.

Avoiding damage to child's skin

Advice about how to avoid damage to a child's skin may vary, depending on the form of EB and the severity of their symptoms. This may include:

• Avoid everyday knocks, bumps and scratches.
• Avoid rubbing their skin in order to help avoid blisters and skin damage. Be extra gentle when picking them up.
• Avoiding clothes that fit tightly or rub the skin.
• Choosing comfortable shoes that fit well. Natural fabric like leather may help to keep their feet cool.
• Keep the child from eating hard or sharp foods that can cause blisters in the mouth.
• Keeping your child as cool as possible in warm weather.
• Wearing clothes made from natural fabrics, such as cotton, to help the child to keep cool.

Infections

Open wounds and raw patches of skin can often become infected. An antibiotic cream may be prescribed.

Pain relief

The need for pain relief medicine will vary, depending on the severity of the child's symptoms. The blisters and the wounds can be very painful. Simple activities, such as moving and walking can be difficult.

Dental care

Good dental hygiene and regular visits to a dentist are important. Soreness caused by blisters inside the child's mouth can make cleaning their teeth difficult.

Feeding

If the baby has blisters in the mouth, it can cause problems with feeding. Get medical advice on how to cope with these problems, whether breastfeeding or bottle feeding.

Child's diet and nutrition

Ask for medical advice about the child's diet. A healthy diet is very important since the healing process makes great demands on the body. Good nutrition is essential to help heal the wounds on the child's skin.

A diet high in calories and protein can be recommended. Also supplements, such as vitamins or iron if they have anemia (iron deficiency).

Genetic counseling

Treatment for EB may include genetic counseling, to provide support and advice, as well as information about how it is inherited and which family members may be affected.

Gene therapy

Research into improving treatments for EB is ongoing. It focuses on managing chronic pain and gene therapy, which involves replacing faulty genes with normal genes, or genes that have been altered.

What are the complications of epidermolysis bullosa (EB)?

There are currently more than 25 known forms of epidermolysis bullosa (EB). Each has different complications.

Complications caused by scarring

In some forms of EB, blisters and open wounds can heal slowly, leaving scar tissue that builds up over time. In EB simplex, scar tissue can thicken and harden skin on the palms of the hands and soles of the feet (hyperkeratosis).

In other forms of EB, the build-up of scar tissue can cause disability, and difficulty with movement. In severe recessive dystrophic EB, scar tissue can build up between fingers or toes so that they join together. Surgery may be needed in order to enable the child to move their fingers again.

Blisters can cause scarring in the mouth and esophagus. It can cause problems with chewing, swallowing food and making eating very painful.

Scarring can also make the esophagus narrower, or cause blockages in it. Surgery may be needed to enable swallowing again. Nutrients may be fed directly to the stomach through a tube.

Blistering and scarring around the anus can make passing stools (faeces) painful and cause constipation.

Secondary skin infection. Blistering can leave skin vulnerable to bacterial infection, particularly staph infection, and increase chances for sepsis.

Sepsis. It occurs when bacteria from a massive infection enter the bloodstream and spread throughout the body. Sepsis is a rapidly progressing, life-threatening condition. It can cause shock and organ failure.

Deformities. Severe forms of epidermolysis bullosa can cause fusion of fingers or toes and abnormal bending of joints, such as fingers, knees and elbows.

Malnutrition. Some forms of epidermolysis bullosa cause blistering of the mouth and other mucous membranes, eating may be difficult. The resulting malnutrition can slow down normal growth.

Anemia. Continuous loss of blood from open sores and possibly inability to take in adequate nutrition may contribute to iron deficiency anemia.

Complications affecting the eyes

Eye complications are more common in the more severe forms of EB. The most frequent complication that affects the eyes is tearing, blistering or scarring of the cornea which is the clear outer layer at the front of the eye. Other eye complications can include:

• blistering of the conjunctiva (the transparent membrane that covers the white part of the eye and the inner eyelid surfaces)
• blisters on the eyelids
• inflamed eyelids
• the eyelid turning outwards (ectropion)

Treatment for eye complications may include lubricating the eye using drops and ointments to help keep it moist.

Dehydration

Skin holds water and fluids inside the body. If a child has widespread blisters, or open wounds, they may lose large amounts of fluids and this can cause severe dehydration.

Other conditions

Some forms of EB can be linked with other conditions:

• Sometimes children with EB simplex also have muscular dystrophy (a genetic condition that leads to slow, progressive wasting of the muscles).
• Some children with EB simplex and junctional EB also have pyloric atresia (a blockage or lack of a small opening between the stomach and the small intestine).

Skin cancer

In some forms of EB, skin cancer can be a common complication that develops between 15 and 35 years of age.

Death

Infants who have a lethal form of junctional epidermolysis bullosa are at high risk of infections and loss of body fluids from widespread blistering. In some cases, blistering of internal organs, may hinder ability to get enough nourishment and, sometimes, to breathe. Many of these infants die in childhood. Milder forms of epidermolysis bullosa, however, may not affect life expectancy.

Remedies for epidermolysis bullosa

Careful wound care and good nutrition are essential. If blisters are left intact, they can grow. This creates a bigger wound when they finally break. Seek medical advice about safe ways to break and drain blisters before they get too large. Products can be recommended to keep the affected areas moist to promote healing and prevent infection, such as gauze containing a moisturizing agent.

When treating wounds:

• Always wash your hands before touching the child's blisters.
• If a soiled dressing sticks, do not pull it off. Soaking the area in warm water loosens the dressing.

If oral or esophageal blisters inhibit the child's ability to eat:

• If drinking from breast or bottle causes the infant to develop blisters, use nipples designed for premature infants, infants with cleft palate or a facial birth defect. A syringe or eyedropper can also be used.
• Reduce foods to pulp with extra liquid (such as broth or milk) to make them softer.

How to prevent epidermolysis bullosa?

Currently, it is not possible to prevent EB. If there is a family history of EB, seek medical advice before deciding to have a baby.

Antenatal diagnosis

If a couple has already had a child with a severe form of EB, they may be offered an antenatal diagnosis if they want to find out whether a later pregnancy is affected. This may involve tests that involve taking samples of tissue from the placenta, amniotic fluid from the womb (amniocentesis), or tissue from the unborn baby (fetal skin biopsy).

Steps to help prevent blisters:

• Gently handle child. Be very gentle. Do not lift your child from under his or her arms. To pick up the child, place him or her on soft material, such as cotton, and support under the buttocks and behind the neck.
  
  
• Moderate home temperature. The home should remain cool with a steady temperature.
  
  
• Keep child's skin moist. Gently apply lubricants, such as petroleum jelly.
  
  
• Dress child in soft materials. Use clothing that is easy to get on and off.
  
  
• Trim child's fingernails regularly. To help prevent scratching.
  
  
• Refrain child from rough activities. Prevent older children from participating in contact sports or other activities in which skin can be rubbed or injured easily.
  
  
• Dressing blisters. Do not apply adhesive bandages or tape to the skin.
  
  
• Avoid hard surfaces and rough materials. Use soft material on car seats and infant seats. Use a water or air mattress on the child's bed and soft sheets and blankets.

Caring for a child with a chronic disease can be stressful. Parents need to provide the child with the emotional support in order to live with a chronic illness. Being different from other children can be extremely difficult. For some people, sharing concerns and information with families in similar circumstances can be beneficial. Joining EB support groups, talking to counselors, clergy or social workers who work with families coping with EB can be helpful.

Written by Stephanie Brunner (B.A.)
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today