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Abstract: The management of patients who have developed a contact dermatitis due to topical drugs requires to stop the suspected drug application, to declare, if severe, the adverse drug reaction to a center for drug safety, to treat the patient with corticosteroid ointments, to perform dermatoallergological investigations e.g. drug patch tests in case of contact eczema and diluted prick tests in case of contact urticaria in order to determine whether the adverse drug reaction was due to excipients or to the drug itself. It is also absolutely necessary to advise the patient concerning the avoidance of topical but also systemic readministration of the responsible molecule. An excipient responsible in inducing a contact sensitization to a topical drug can also be found in cosmetics, the name of the responsible excipient has to be given to the patient under the common name but also under the INCI and/or CFTA name. When the drug itself is responsible in inducing a contact allergy it is necessary to determine if cross reactions with other drugs can occur and if the responsible molecule can induce systemic cutaneous adverse drug reactions if the drug is systemically readministred. Among NSAID there is no cross reactions between bufexamac and diclofenac, between salicylamide, glycol salicylate, salicylic acid and acetylsalicylic acid. In case of photosensitization 1) to ketoprofen or 2) piroxicam the topical and/or systemic administration of the following molecules are contraindicated with respectively 1) ketoprofen, tiaprofenic acid, fenofibrate, oxybenzone or 2) piroxicam, thimerosal. A patient sensitized to corticosteroid ointment has to be tested in order to determine which corticosteroid classes are sensitizing. The topical and systemic administrations of molecules belonging to the sensitizing classes (A, B, C, D1 or D2) have to be forbidden. In general, a contact dermatitis due to an antimicrobial drug induces a contraindication in further topical or systemic uses of the drug and to all the molecules belonging to the same class. In most of the cases there is no risk in systemically administering iodine, sulfites or excipients in a sensitized patient who had developed a contact dermatitis to topical medications. [Copyright &y& Elsevier]

Abstract: Occupational dermatitis (irritant dermatitis, contact urticaria and contact eczema) is frequent among healthcare workers. Irritant hand dermatitis, the most common occupational dermatitis, occurs often in individual who work in a humid environment, who handle disinfectants, and who are required to wash their hands frequently; atopic dermatitis is a risk factor for this condition. Natural rubber latex present in rubber gloves is the most common cause of contact urticaria. Contact eczema can be induced by rubber accelerators (for example, thiurams) present in gloves, and also by disinfectants (glutaraldehyde, dodecyldimethylammonium), disinfectants and detergents, hand creams, acrylates (in dentists), and echography gels. Nurses sometimes develop contact dermatitis to drugs they handle; these allergies should be diagnosed by appropriate skin testing because sensitized individuals may develop a severe, generalized cutaneous adverse reaction if they are subsequently exposed systemically to the sensitizing drug. [Copyright &y& Elsevier]

Recent studies have emphasized the value of drug patch tests, in addition to, prick and intradermal tests to determine the molecule responsible for cutaneous adverse drug reactions (CADR), also known as drug eruptions. The value of drug patch tests depends on the clinical features of the CADR, and they are valuable in the investigation of drug reactions, such as generalized eczema, systemic contact dermatitis, maculopapular rashes, toxic epidermal necrolysis, and fixed drug eruptions. Their sensitivity also depends on the particular drug involved. Guidelines for performing prick, ID and patch tests, published in 2001, are analyzed in the present article. We also report on the information published more recently on how to perform the tests, how to interpret them, new drugs reported to yield positive reactions and, finally, how to define the relevance and the specificity of drug patch tests in the workup of cutaneous drug allergies. [Copyright &y& Elsevier]

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]