Epithelial adhesion disorders (EAD) are a group of heritable skin diseases, which are characterized by chronic fragility and blistering of the skin and mucous membranes. The blisters and erosions are mostly induced by minimal trauma or, sometimes, occur spontaneously. These diseases have a high personal, medical and socio-economic impact on the life of the affected individuals and their families. Complications can occur since many organs are secondarily affected and, in addition to life-long daily skin care, other medical treatments are frequently required. Currently, no specific cure exists for the EAD.
Due to diminished adhesion of the skin layers, the epidermis and the dermis, to each other, even very slight mechanical stress increases the tendency of the skin to blister. This mainly concerns the skin on the hands and feet, but also other areas of the body, the mucous membranes (e.g. in the mouth and eyes) and membranes of the digestive tract. The blisters can be filled with blister secretions or blood, depending on the depth of the affected skin layers. If the deeper layers are affected, the healing process of the resulting wounds often leads to scarring and deformities, which in turn can cause contractures (e.g. of the hands and feet). Depending on the subtype, the spectrum of symptoms of the EAD is very broad, ranging from minimal skin fragility to very severe symptoms with general complications. In some forms of EAD, also nails, hair and teeth may be involved.
The distinct forms of the EAD group are caused by mutations in the genes coding for protein components of the dermal-epidermal junction zone. As a result of the mutations, the skin cells produce functionally abnormal proteins - or no protein at all. Lack of the protein or its proper function then leads to diminished resistance of the skin  to mechanical stress and shearing forces. The main groups of EAD are:

Epidermolysis bullosa simplex (EBS). This is in general a mild form. Blister formation usually occurs more during childhood than in adulthood, and the healing of the blisters occurs without scarring or skin atrophy.

Junctional epidermolysis bullosa (JEB). Very different forms of JEB exist, both mild and moderate forms, but also early lethal forms of JEB. Healing without scarring is usually observed; however, skin atrophy, nail dystrophy and hair involvement often develop.

Dystrophic epidermolysis bullosa (DEB). DEB can either take a mild or a more severe form. Healing with scars is usual, because the deeper layers of the skin and mucous membranes are affected by blistering. In severe cases, bad scarring can cause mutilation and contractures of the hands and feet.

Kindler syndrome (KS). KS is a rare EAD subtype, which shows a changing picture with age. In early childhood, the symptoms include skin blistering and sensitivity to sun light. These improve with age, but variations of skin pigmentation and atrophy (thin skin) develop. Sometimes, thickened skin of palms and soles, and inflammation and mild scarring of mucous membranes are observed.

Diagnostic tests for EAD. The level of blistering in the skin cannot be determined externally. Therefore, a skin sample (biopsy) is needed for microscopic determination of the general EAD form. Final precise diagnosis can only be determined by genetic mutation analysis, for which a blood sample is required.