The cause of Atopic Dermatitis is impairment of the barrier function of the skin. This impairment is caused by decreased levels of two epidermal compounds: Ceramide and Filagrin. Ceramide is decreased because of a genetically determined increase in an enzyme that breaks down a Ceramide building block. Filagrin is decreased because of under-expression of the gene that govern Filagrin formation.
Once the skin barrier becomes impaired, it becomes more porous and Atopic Dermatitis will start to become visible. This leads to a much more sensitive skin, because it becomes easy for irritants to penetrate into the skin. The skin also becomes more susceptible to infection that can further aggravate this dermatitis.
The goal of treatment in Atopic Dermatitis is therefore to repair the skin barrier function.