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Résumé Après les antibiotiques, les AINS sont les médicaments les plus souvent responsables de réaction d’hypersensibilité (1 à 3 % parmi la population générale et jusqu’à 30 % dans la population présentant un asthme, une rhinosinusite chronique ou une urticaire chronique spontanée). Ces réactions peuvent être allergiques (médiées par les IgE ou par des lymphocytes T) ou non allergiques (liées à la libération de médiateurs par les mastocytes, les basophiles notamment). Les premières réactions (allergiques) sont spécifiques d’un AINS ou d’une famille chimique d’AINS tandis que les secondes (non allergiques) sont induites par des AINS de familles chimiques différentes (réactivité croisée pharmacologique ou « cross-intolérants »). Les différents phénotypes cliniques ont ainsi été redéfinis récemment par le groupe ENDA/EAACI dans l’objectif de préciser les moyens diagnostiques à mettre en œuvre et une prise en charge standardisée pour chaque patient ; la méthodologie est reprise dans cet exposé. After antibiotics, NSAIDs are the drugs most often responsible for drug hypersensitivity reactions, involving 1–3% of the general population and up to 30% of people with asthma, chronic rhinosinusitis or spontaneous chronic urticaria. These reactions may be allergic (IgE- or T cell-mediated) or non-allergic (due to the release of mediators from mast cells and basophils). The allergic reactions are specific to an NSAID or to a chemical family of NSAIDs, while the non-allergic reactions are induced by NSAIDs of different chemical families (pharmacological cross-reactivity or “cross-intolerance”). The different clinical phenotypes have been redefined recently by the ENDA/EAACI group aiming to clarify the diagnostic methods and to implement standardized management for each patient; the methodology is included in this presentation. [ABSTRACT FROM AUTHOR]

Introduction. – Malassezia are lipophilic yeasts, saprophytic on human skin. For the past 20 years, Malassezia were thought to be involved in the pathogenesis of certain forms of head and neck dermatitis (HND). The aim of the present study was to investigate the role of this organism in HND. We also studied possible cross-reactivity with two other yeasts, Candida albicans and Saccharomyces cerevisiae.Patients and methods. – Fifty-three subjects were included: 25 patients with HND, 10 patients with generalized atopic dermatitis (AD) and 18 healthy controls. The 25 patients with HND had yeast cultures taken for Malassezia, and all 53 subjects had patch tests, skin prick tests and IgE antibody assays for Malassezia, C. albicans and S. cerevisiae. The HND patients were then treated with ciclopiroxolamine, a topical antimycotic.Results. – We found no statistically significant relationship between the results of yeast cultures, skin tests and the serological results or the results of the antimycotic treatment in these subjects. We did find increased sensitivity to Malassezia in patients with AD compared to the healthy controls, but there was no statistical difference between HND patients and patients with generalized AD. Nevertheless, for the entire group of patients, there was a significant relationship between results of skin prick tests and specific antibodies for Malassezia, C. albicans and S. cerevisiae, suggestive of possible cross-reactivity between these three yeasts.Conclusion. – The results lead us to propose two hypotheses: (1) Patients may be sensitized to yeast proteins but have no signs of an allergy requiring antifungal treatment, i.e. HND. (2) Patients with HND might be sensitized to several yeasts, and they would need systemic antifungal treatment that is active on Malassezia and C. albicans and, in addition, a S. cerevisiae-free diet. [Copyright &y& Elsevier]