Epidermolysis Bullosa

Epidermolysis Bullosa (EB) is an inherited group of diseases that are characterized by blistering lesions on the skin and mucus production areas. These may occur anywhere on the body but most commonly appear at sites of friction and minor trauma such as the feet and hands. Blisters may also occur on internal organs, such as the esophagus, stomach and respiratory tract, without any apparent friction.

The EB conditions result from genetic defects of molecules to adhere to one another. Loss of adhesion results in blister formation. There are 3 major types of EB based on different sites of blister formation within the skin structure. Epidermolysis Bullosa simplex (EBS) affects the epidermis or uppermost layer of skin cells. Junctional Epidermolysis Bullosa (JEB) affects the layer of skin between the epidermis and the dermis. Dystrophic Epidermolysis Bullosa (DEB) affects the deeper layer of skin cells.

Within each of these types of EB there are various subtypes. Varying degrees of severity that range from mild to severe are found with each EB type.

EB is an inherited disease, which means that you have inherited one or two EB genes. EB usually occurs at birth or shortly after. Males and females are equally affected. Occasionally EB may be mild enough at birth not to be apparent and it is not until the child is older or reaches adulthood before it is detected.

Since there are varying severities and subtypes within the EBS, each presents unique symptoms. There are four subtypes of EBS. Weber-Cockayne is the most common form of EBS. Blisters develop on the hands and feet in response to the friction of learning to crawl or walk. The wounds heal without scarring, but may result in thickening of the skin on soles and palms. Koebner is a generalized form of EBS where blisters develop all over the body, but most commonly on the hands, feet, and extremities, and mild appearances on mucus production areas and nails. The skin of the palms and soles will also thicken and may develop plaques. Dowling Meara is a severe form of EBS, with blistering on the face, trunk and limbs, nails, and possibly internal organs. The skin thickens with calluses so severe that joint movement may be affected. EB with muscular dystrophy is due to a plectin mutation which causes variable blistering followed by a case of muscular dystrophy later in life.

JEB also shows four subtypes. Herlitz JEB is the most severe form where blisters appear all over the body, in the mucus production areas and on internal organs, often starting with just a small single blister. Usually, a hoarse cry or cough is indicative of internal organ involvement. Complications often lead to infant death before age two. Non-Herlitz JEB shows blistering and mucosal involvement with particular focus on the scalp, nails, and teeth. This can still cause complications which lead to infant death. Generalized atrophic benign EB starts with mild blistering and involvement of the scalp, nail and teeth. Blisters worsen in warmer climates and heal with an atrophied appearance. EB with pyloric atresia refers to blistering in addition to pyloric atresia — an abnormal closing of an opening in the body.

DEB only has two subtypes. Dominant DEB manifests similarly to Weber-Cockayne with blistering focused in high-friction areas, resulting in white spots and scarred healing. Recessive DEB presents with severe blistering in large areas of the skin and mucus production aresa. The blistering heals with such severe scarring mobility may be limited and digits may fused together (mitten hands). Complications often lead to skin cancers or death.

Differential Diagnosis (Other conditions with similar appearance)

Pemphigoid
Dyshidrotic Eczema
Friction Blisters
Linear IgA dermatosis
Pemphigus vulgaris
Thermal Burns

Diagnosis is performed through clinical inspection to confirm correct diagnosis. Because of the number of variations and subtypes, it is important to determine the affected skin layer and severity of blistering.