[Atopic dermatitis].

For the past decades, the prevalence of atopic dermatitis is on the rise. Three phases of the disease are recognized according to the age of the patient, either in the newborn age, in infancy or after puberty. A partial enzymatic defect in delta-6 desaturase has been reported. Such metabolic anomaly would be responsible for the alterations in both the skin barrier function and in the Th2 inflammatory reactions in part mediated through IgE. Some microorganisms colonizing the skin play an important causal role in the clinical exacerbations. The influence of food allergy on atopic dermatitis remains obscure and often unconvincing. By contrast, irritant and allergic challenges from the environment exhibit an undisputable worsening effect. The prevention relies on the eviction of predisposing factors and is favourably influenced by emollients specifically designed for atopic dermatitis. A food supplementation in alpha-linoleic acid and some specific chinese herbal remedies might well be useful. The treatment relies primarily on topical applications of corticoids. Puva-therapy, UVB phototherapy and immunomodulation by cyclosporine are indicated for difficult cases.