Diseases & Conditions

Epidermolysis bullosa

Epidermolysis bullosa is a group of skin conditions whose hallmark is blistering in response to minor injury, heat, or friction from rubbing or scratching. There are three main types of epidermolysis bullosa, with numerous subtypes. Most are inherited.

Most types of epidermolysis bullosa initially affect infants and young children, although some people with mild forms of the condition don't develop signs and symptoms until adolescence or early adulthood. Some infants are born with blisters. Mild forms of epidermolysis bullosa may improve with age, but severe forms may cause serious complications and can be fatal.

There's no cure for epidermolysis bullosa. Treatment depends on the severity, but often is aimed at preventing pain, infection and other complications.

The primary indication of epidermolysis bullosa is the eruption of fluid-filled blisters (bullae) on the skin, most commonly on the hands and feet in response to friction. Blisters of epidermolysis bullosa typically develop in various areas, depending on the type. In mild cases, blisters heal without scarring.

Depending on the type of the condition, blistering may be present at birth, appear during infancy or occur during adolescence or early adulthood. The three main types are:

• Epidermolysis bullosa simplex, which usually begins at birth or in early infancy
• Junctional epidermolysis bullosa, which generally begins at birth and is usually severe
• Dystrophic epidermolysis bullosa, which generally begins at birth or in early childhood

Epidermolysis bullosa simplex is the most common and least severe type, with the most common and mildest subtype being Weber-Cockayne type, which typically involves blistering of the palms and soles.

Signs and symptoms of epidermolysis bullosa may include:

• Blistering of your skin — how widespread and severe depends on the type
• Deformity or loss of fingernails and toenails
• Internal blistering, including on the throat, esophagus, upper airway, stomach, intestines and urinary tract
• Skin thickening on palms and soles of the feet (hyperkeratosis)
• Scalp blistering, scarring and hair loss (scarring alopecia)
• Thin-appearing skin (atrophic scarring)
• Tiny white skin bumps or pimples (milia)
• Dental abnormalities, such as tooth decay from poorly formed tooth enamel
• Excessive sweating
• Difficulty swallowing (dysphagia)

Other types
Researchers have proposed a fourth type — hemidesmosomal epidermolysis bullosa — one form of which is associated with muscular dystrophy, an inherited disease that involves progressive weakening of muscles.

In another rare type — epidermolysis bullosa acquisita, which isn't inherited — the blistering occurs as the result of the immune system mistakenly attacking healthy tissue. It's similar to a condition called bullous pemphigoid, which also may be related to an immune system disorder. This form of the condition has been associated with Crohn's disease, an inflammatory bowel disease.

Your skin comprises an outer layer (epidermis) and an underlying layer (dermis). The area where the layers meet is called the basement membrane zone. Where blisters develop depends on the type of epidermolysis bullosa.

In most cases, epidermolysis bullosa is inherited. Researchers have identified more than 10 genes involved with skin formation that, if defective, may cause a type of epidermolysis bullosa. It's also possible to develop epidermolysis bullosa as a result of a random mutation in a gene that occurred during the formation of an egg or sperm cell.

Epidermolysis bullosa simplex
In epidermolysis bullosa simplex, the most common and generally mildest form, the faulty genes are those involved in the production of keratin, a fibrous protein in the top layer of skin. The condition causes the skin to split in the epidermis, which produces blisters.

If you have epidermolysis bullosa simplex, it's likely you inherited a single copy of the defective gene from one of your parents (autosomal dominant inheritance pattern). If one parent has the single faulty gene, there's a 50 percent chance their offspring will have the defect.

Junctional epidermolysis bullosa
In this usually severe type of the disorder, the faulty genes are involved in the formation of thread-like fibers (hemidesmosomes) that attach your epidermis to your basement membrane. This gene defect causes tissue separation and blistering in your basement membrane zone.

Junctional epidermolysis bullosa is the result of both parents carrying and passing on the defective gene (autosomal recessive inheritance pattern), although neither parent may have the disorder (silent mutation). If both parents have the faulty gene, there's a 25 percent chance their offspring will have the defect and develop the disorder.

Dystrophic epidermolysis bullosa
In this type, whose subtypes range from mild to severe, the faulty genes are involved in the production of a type of collagen, a protein in the fibers that attach your epidermis to your dermis. As a result, the fibers are either missing or nonfunctional.

Dystophic epidermolysis bullosa can be either dominant or recessive.

Contact your doctor promptly if your child is born with or develops blisters, particularly if there's no apparent reason for them. Blisters can lead to infection and deformity. Your doctor can show you how to care for them properly and advise you on ways to prevent them.

For adolescents and adults, see a doctor if blisters suddenly develop for no apparent reason or if you experience problems swallowing or breathing.

Treatment of epidermolysis bullosa aims mainly at preventing complications and easing discomfort from blistering.

Skin care
Blisters may be large and, once broken, susceptible to infection and fluid loss. Your doctor may instruct you in puncturing blisters with a sterile needle. Leaving the roof of the blister intact allows for drainage of the blister while protecting the underlying skin. Your doctor may recommend applying an antibiotic ointment or petroleum jelly or other moisturizing substance before applying a nonsticking bandage.

For wounds that don't heal over time, your doctor may recommend skin grafts, using either your own skin or your child's own skin from an unaffected area or manufactured skin. Covering the wound with skin can help spur healing.

Surgery
Repeated blistering and scarring can cause deformities, such as fusing of the fingers or toes or abnormal bends in the joints (contractures). Your doctor may recommend surgery to correct these deformities, particularly if they interfere with normal motion.

Blistering and scarring of the esophagus may lead to esophageal narrowing, making eating difficult. Your doctor may recommend surgery to widen (dilate) the esophagus. Using light sedation, the surgeon positions a small balloon in the esophagus and inflates it to dilate the area.

If feeding is impossible, a tube (gastrostomy tube) may be implanted to deliver food directly to the stomach. Feedings through the tube may be delivered overnight using a pump.

Physical therapy
Working with a physical therapist can help ease the limitations on motion caused by scarring and contracture.