Definition of Epidermolysis bullosa:

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

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.