Atopic Dermatitis and Allergen Hypersensitivity: State of the Art - (Pages 1-7)
Division of Allergy and Clinical Immunology, Department of Paediatrics, University of Roma “La Sapienza”, Roma, Italy
Abstract: The current growing enthusiasm for atopic dermatitis (AD) is clearly reflected in the range of current attitudes on the subject. What are considered to be its protean manifestations are frequent challenges to the paediatrician and other specialists working with children. AD may occur not only in man, but also in other vertebrates. However, it must be assumed that AD has always been an affection of our species. Hippocrates (460-370 BC) reported urticaria and gastrointestinal upset following cow’s milk (CM) ingestion. Lucretius (98-55 BC) wrote that one man’s meat is another man’s poison. Galen (131- 219) described allergy to goat’s milk. At the turn of this century the first description of acute shock due to CM allergy (CMA) and fatal CMA were published. In his pioneer studies of food allergy (FA), Schloss was the first to evaluate skin tests for the diagnosis of FA. Since then, a vast array of symptoms and disorders have been attributed to FA, many of which occur with other conditions. In addition to this, the lack of a single, practical diagnostic test has contributed to the polarization of the scientific controversy between those who believe in and those who deny FA existence. Terminology has also been confusing. A correct use of definitions is necessary for a proper epidemiologic evaluation of the conditions and an accurate diagnostic and therapeutic approach. While this concept was fundamentally correct, it was also too easily weakened by ignoring this prerequisite to be fully acceptable, and this led to an equally disordered use of the term hypersensitivity, since allergy had become a word used to embrace all possible forms of adverse reactions. AD is associated with patchy, characteristically distributed areas of cutaneous eczema, with intense itching and subsequent lichenification of the skin. Cutaneous automic dysfunction (increased vasoconstriction) and xerosis (dryness of the skin) commonly occur in the affected children. In addition, profound immunological dysregulation with various immune alterations has been described in affected children. Most children produce IgE antibodies to a number of food and inhalants allergens, at the point that a minuscule offending quantity can trigger a reaction by skin contact or by inhalation.
Keywords: IgE antibodies, allergic inflammation, eosinophils, T lymphocytes, homing receptors, inhalant and food allergens.