Epidermolysis bullosa Health Article

Definition

Epidermolysis bullosa is a group of inherited disorders in which skin blisters develop in response to minor injury.

Alternative Names

Junctional epidermolysis bullosa; Dystrophic epidermolysis bullosa; Hemidesmosomal epidermolysis bullosa; Weber-Cockayne syndrome

Causes, incidence, and risk factors

There are four main types of epidermolysis bullosa:

• Epidermolysis bullosa simplex
• Junctional epidermolysis bullosa
• Dystrophic epidermolysis bullosa
• Hemidesmosomal epidermolysis bullosa

Another rare type of epidermolysis bullosa, called epidermolysis bullosa acquisita, is an autoimmune disorder. This may be indistinguishable from another autoimmune skin disorder called mucous membrane pemphigoid.

Depending on the type present, epidermolysis bullosa varies in severity from minor blistering of the skin to a lethal form involving other organs. The condition generally starts at birth or soon after that. Epidermolysis bullosa acquisita, however, usually appears in adults over age 50, although it has been reported in children. Also, mild cases of epidermolysis bullosa simplex may remain undiagnosed until adulthood.

The classification of epidermolysis bullosa is complicated. Even within the main types mentioned, there are many different subtypes of this condition. For example, Weber-Cockayne is the most common form of epidermolysis bullosa simplex. This type involves blistering of the palms and soles and may include excessive sweating.

All of the different types of epidermolysis bullosa are generally inherited. Therefore, having a family history of the disease, especially an affected parent, is a risk factor. The inheritance pattern may be dominant or recessive. A dominant form means that an offspring can inherit the gene or trait from one affected parent. The recessive form means that both parents must carry a gene and transmit that gene to the offspring in order for the infant or child to be affected. The recessive forms of epidermolysis bullosa tend to be more severe.

The hallmark of these conditions is the formation of large, fluid-filled blisters that develop in response to minor trauma. Some infants may have large blisters at birth. Others start shortly after birth. Chafing (wearing away) of the skin, rubbing, or even increased room temperature may cause blisters to form.

In the severe forms, scarring after blister formation may cause deformities, fusion of the fingers and toes, and contracture deformities (for example, at the fingers, elbows and knees). If the mouth and esophagus are involved, blistering and scarring lead to feeding and swallowing difficulties.

Secondary infection is common.

Symptoms

Symptoms depend on the type of epidermolysis bullosa, but can include:

• Blistering of the skin as a result of minor trauma or temperature change
• Blistering present at birth
• Nail loss or deformed nails
• Blistering in or around the mouth and throat, causing feeding difficulty or swallowing difficulty
• Blistering around the eyes and nose
• A hoarse cry, cough, or other respiratory difficulties
• Dental abnormalities such as tooth decay
• Alopecia (hair loss)
• Milia (tiny white bumps or pimples)

For epidermolysis bullosa acquisita, there is an association with Crohn's disease (an inflammatory bowel disease) and, possibly, lupus. Symptoms of these conditions may be present, therefore, in adults who present with this type of epidermolysis bullosa.

Signs and tests

Your physician may suspect epidermolysis bullosa based upon the appearance of the skin. A skin biopsy, genetic testing, and special microscopic tests applied to the skin samples are needed to confirm the diagnosis. Special skin tests also distinguish epidermolysis bullosa acquisita presenting in a child (which does happen on rare occasion) from other forms of epidermolysis bullosa.

Your doctor may also do a blood test to see if there is anemia. If there are wounds that are healing poorly, a culture may be done to check for bacterial infection.

If swallowing or feeding difficulties are present, upper endoscopy or an upper GI series may be performed.

In an infant with epidermolysis bullosa or suspected epidermolysis bullosa, growth curves will be followed very closely.

If contractures are present, the range of motion of limbs will be tested.