The number of rare and complex skin disorders is extremely high and their aesthologies and clinical features vary a lot. They may concern the development/growth (genodermatoses including germ-line genetic disorder and somatic cell genetic disorders) or a high genetic predisposition (such as vascular disorders, autoimmune, inflammatory and proliferative cutaneous diseases).

Most of genodermatoses are first detected in childhood, persisting through life, but some may also arise in later years. In the same way auto-immune or proliferative cutaneous disorders, frequent among adults, can also be observed among children.

In the meantime, even though rare and complex dermatological diseases are heterogeneous they can be interconnected and share common management in the care and the field of research. The pathophysiological mechanisms behind these different rare skin diseases are extremely complex and intricate.

The understanding of some skin diseases is the key for understanding the others and provides a better knowledge on skin biology. In that respect, the cooperation between the thematic groups composing the ERN-Skin is a massive asset.

These diseases are frequently difficult to diagnose or to classify with no clear diagnostic guidelines for most of them. The diagnosis consists of a full assessment of the skin and mucous membrane as well as other systems.

Only expert dermatologists are able to make the differential diagnosis leading to the precise recognition necessary for adequate treatment and prognosis. Skin conditions may also trigger other disorders, necessitating the involvement of other specialists such as radiologists, cardiologists, surgeons etc.

Within the structure of the ERN-Skin, dermatologist play a key role in organising the multidisciplinary care, as skin knowledge of other medical professionals is in general quite poor. As coordinator of the multidisciplinary management they ensure both an integrated management and continuity of care with the community health care system.