Epidermolysis Bullosa

Overview of Epidermolysis Bullosa

Epidermolysis bullosa is a group of rare conditions in which the skin becomes brittle and easily blistered. Tears, sores, and blisters on the skin occur when something rubs or hits the skin. They can appear anywhere on the body. In severe cases, blisters can also form inside the body, such as in the mouth, esophagus, stomach, intestines, upper respiratory tract, bladder, and genitals.

Most people with epidermolysis bullosa inherit the mutated (altered) gene from their parents. The gene mutation changes how the body makes proteins that help skin bond with each other and stay strong. If you have epidermolysis bullosa, one of these proteins is not made correctly. The layers of skin don't usually bond together, making the skin tear and blister easily.

The main symptom of epidermolysis bullosa is fragile skin that leads to blistering and tearing. Symptoms of the disease usually begin at birth or during infancy and range from mild to severe.

There is no cure for the disease; however, scientists continue to explore possible treatments for epidermolysis bullosa. Your doctor treats symptoms, which may include relieving pain, treating wounds caused by blisters and tears, and helping you fight illness.

Who gets epidermolysis bullosa?

Anyone can get epidermolysis bullosa. It occurs in all racial and ethnic groups and affects men and women equally.

Types of epidermolysis bullosa

There are four main types of epidermolysis bullosa. The skin has a top or outer layer called the epidermis and a dermis layer that lies underneath the epidermis. The basement membrane is where the layers of skin meet. Doctors determine the type of epidermolysis bullosa based on the location of skin changes and the identified gene mutation. Types of epidermolysis bullosa include:

• Epidermolysis bullosa simplex: blisters occur in the lower part of the epidermis.
• Borderline epidermolysis bullosa: Blisters occur at the top of the basement membrane due to attachment problems between the epidermis and the basement membrane.
• Dystrophic epidermolysis bullosa: Blisters occur in the upper dermis due to attachment problems between the basement membrane and the upper dermis.
• Kindler's syndrome: blisters occur in several layers of the skin, including the basement membrane.

Researchers have identified more than 30 subtypes of the disease, which are grouped into four main types of epidermolysis bullosa. By knowing more about the subtypes, doctors can focus on treating the disease.  

The fifth type of the disease, acquired epidermolysis bullosa, is a rare autoimmune disease in which the body's immune system attacks a specific type of collagen in a person's skin. Sometimes this occurs with another disease, such as inflammatory bowel disease. Rarely does a drug cause a disease. Unlike other types of epidermolysis bullosa, symptoms can appear at any age, but many people develop symptoms in middle age.

Epidermolysis bullosa symptoms

Epidermolysis bullosa symptoms vary depending on the type of epidermolysis bullosa. Everyone with this condition has fragile skin that easily blisteres and tears. Other symptoms, by type and subtype, include the following.

• Epidermolysis Bullosa Simplex is the most common form of the disease. People with the mild subtype develop blisters on the palms of their hands and the soles of their feet. In other, more severe subtypes, blisters appear all over the body. Depending on the subtype of the disease, other symptoms may include:
  • Thickening of the skin on the palms of the hands and soles of the feet.
  • Rough, thickened, or missing fingernails or toenails.
  • Blisters inside the mouth.
  • Change in pigmentation (color) of the skin.
• Bullous nodular epidermolysis usually heavy. People with the most severe form may have open blisters on their face, torso, and legs, which can become infected or cause severe dehydration due to fluid loss. Blisters can also develop in the mouth, esophagus, upper respiratory tract, stomach, intestines, urinary system, and genitals. Other symptoms and problems associated with the disease may include:
  • Rough and thickened or missing fingernails and toenails.
  • Thin skin appearance.
  • Blisters on the scalp or hair loss with scarring.
  • Malnutrition resulting from inadequate intake of calories and vitamins due to blistering of the mouth and gastrointestinal tract. 
  • Anemia.
  • Slow overall growth.
  • Poorly formed tooth enamel.
• Bullous dystrophic epidermolysis has slightly different symptoms, depending on whether the disease is dominant or recessive; however, most people have a recessive subtype.
  • Recessive subtype: Symptoms range from mild to severe and may include:
    • Blisters usually appear on large areas of the body; in some milder cases, blisters may appear only on the feet, elbows, and knees.
    • Loss of nails or rough or thick nails.
    • Scarring of the skin, which can cause the skin to become thick or thin.
    • Milia are small white bumps on the skin.
    • Itching.
    • Anemia.
    • Slow overall growth.

Severe forms of the recessive subtype can result in eye involvement, loss of teeth, blistering of the mouth and gastrointestinal tract, and fusion of fingers or toes. The risk of developing skin cancer is also high. This cancer tends to grow and spread faster in people with epidermolysis bullosa than in people without the disease.

• • Dominant subtype: Symptoms may include:
    • Blisters only on arms, legs, elbows and knees.
    • Changing the shape of the nails or falling out of the nails.
    • Milia.
    • Blisters inside the mouth.

• Kindler syndrome has no subtypes, and blisters can form in all layers of the skin. The blisters usually appear on the arms and legs and, in severe cases, spread to other parts of the body, including the esophagus and bladder. Other symptoms include thin, wrinkled skin; scarring; milium; and skin sensitivity to sunlight.

Causes of epidermolysis bullosa

Mutations (changes) in genes inherited from parents cause most forms of epidermolysis bullosa. Genes carry information that determines which traits are passed on to you from your parents. We have two copies of most of our genes, one from each parent. People with this condition have one or more genes that carry incorrect instructions for making certain proteins in the skin.

There are two types of inheritance models:

• Dominant, which means you inherit one normal copy and one copy of the gene that causes epidermolysis bullosa. The abnormal copy of the gene is stronger or "dominates" the normal copy of the gene, causing disease. A person with a dominant mutation has a 50% chance (1 in 2) of passing the disease on to each of their children.
• Recessive, which means that your parents do not have the condition, but both parents have an abnormal gene that causes epidermolysis bullosa. When both parents carry recessive genes, there is a 25% (1 in 4) chance of having a child with the condition for each pregnancy. There is a 50% chance (2 out of 4) for a pregnancy to have a baby that inherits one abnormal recessive gene, making it a carrier. If one parent has a recessive gene mutation, all of their children will carry the abnormal gene, but will not necessarily have epidermolysis bullosa.

Researchers know epidermolysis bullosa acquired is an autoimmune disease, but they don't know what causes the body to attack collagen in a person's skin. Occasionally, people with autoimmune inflammatory bowel disease also develop acquired epidermolysis bullosa. In rare cases, drugs cause the disease.