[Immunoallergology in children: diagnosis and treatment]

Atopy is the most frequent allergic disease in western countries: about 30% of children are suffering from various forms of its manifestations. During the 20th century, its frequency gradually increased. This is not only true for sensitization (presence of specific immunoglobulin E (IgE) in the skin or in the serum), but also for clinical symptoms associated with sensitization. It is usually a disease of skin and mucosae, but atopy can also become systemic (anaphylaxis). Hygienist hypothesis (reduction of infectious diseases and Th1 pressure) gives a possible explanation to the impressive increase of allergic diseases during the last decades. In the child, atopic dermatitis and food allergies are first observed (allergic march): 5 allergens explain more than 85% of cases (white egg, milk, peanuts, fish and nuts). Skin prick tests are more sensible than specific IgE measurements in the serum; they are usually done before. Provocation tests (labial and oral) can confirm the diagnosis when necessary. Four families of aeroallergens are described (pollens, house dust mites, pets and moistures). Eviction is the first line of treatment, than drugs are prescribed to reduce symptoms and inflammation (corticosteroids, antihistamine). Desensitization and immunomodulators that can induce tolerance are also proposed in defined situations.