Audrey Nosbaum

Allergic and irritant contact dermatitis

Irritant and allergic contact dermatitis are common inflammatory skin diseases induced by repeated skin contact with low molecular weight chemicals, called xenobiotics or haptens. Although both diseases may have similar clinical presentations, they can be differentiated on pathophysiological grounds. Irritant contact dermatitis (ICD) is a non-specific inflammatory dermatitis brought about by activation of the innate immune system by the pro-inflammatory properties of chemicals. Allergic contact dermatitis (ACD) corresponds to a delayed-type hypersensitivity response with a skin inflammation mediated by hapten-specific T cells. Recent progress in the pathophysiology of chemical-induced skin inflammation has shown that ICD and ACD are closely associated and that the best way to prevent ACD is to develop strategies to avoid ICD. The immunological diagnosis of ICD or ACD requires investigation of the presence (ACD) or absence (ICD) of antigen-specific T cells. The detection of T cells can be performed in the skin (collected from ACD lesions or positive patch tests) and/or in the blood, particularly by using the enzyme-linked immunospot assay (ELISPOT). This method, recently developed in ACD to metals, offers a new biological tool enabling the immunobiological diagnosis of ACD.

Negativity of the basophil activation test in quinolone hypersensitivity: a breakthrough for provocation test decision-making.

Background: Quinolone hypersensitivity reactions are being more frequently reported. Skin tests in investigations of patients are known to not be fully reliable. The provocation test thus remains the gold standard in the definitive diagnosis of allergy, despite the risks involved. The aim of this study was to evaluate basophil activation tests (BATs) in the diagnosis of immediate-type reactions to quinolones. Methods: Thirty-four patients who presented an immediate-type hypersensivity reaction less than an hour after quinolone administration were studied. The allergologic workup of these patients consisted of a careful clinical history, a skin test and a BAT with the culprit quinolone. If not contraindicated, and in the case of high probability of a nonallergic reaction, provocation tests were performed to assess the nonimmunologic nature of the hypersensitivity. Results: Among the 34 patients studied, 17 (50%) presented a negative BAT to the suspected quinolone, while the other 17 (50%) patients presented a positive BAT for quinolone at the time of their reaction. Among the 17 patients with negative BATs, 15 (2 of whom had had positive skin tests) had quinolone successfully reintroduced. Conclusions: Our report suggests that the BAT, if negative for the culprit quinolone, is a valuable tool in the decision whether or not to perform provocation tests in patients with a history of immediate-type reaction to quinolones, in order to exclude an allergic reaction.

Chronic spontaneous urticaria is not an allergic disease

The links between chronic urticaria, IgE sensitization and allergy have been much discussed but little studied. We investigated IgE sensitization and allergy in 128 adult chronic urticaria patients during 2006-2008. During a one-day hospitalisation, the patients answered a standardized questionnaire and underwent blood serum analysis, physical tests and skin prick-tests. IgE sensitization to environmental allergens was defined by the positivity of at least one skin prick test and/or elevated levels of serum IgE ≥ 300 Kui/L. The chronic urticaria was considered allergic if: i) a high correlation between positive skin prick tests to a clinically relevant allergen and the case history was found; ii) complete remission of urticaria occurred within two months of allergen withdrawal. Of 105 patients with interpretable skin prick tests, 46.7% were IgE sensitized. Two patients had clinically relevant positive skin prick tests but their chronic urticaria had many other triggering factors and neither was in complete remission after withdrawal of these allergens. IgE sensitization is higher in chronic urticaria patients than in the global adult population, suggesting that it is one important etiopathogenic factor in chronic urticaria. However, it cannot be considered as the expression of an IgE-mediated allergy but as a chronic inflammatory disease, more frequent in IgE sensitized people and favoured by multiple factors, among which IgE-mediated allergy is exceptional.

Patch testing in atopic dermatitis patients.

The exposure of atopic dermatitis (AD) patients to aeroallergens or food allergens can exacerbate or maintain the disease. Atopy patch tests (APTs) are able to identify these triggering factors and consist of the epicutaneous application of allergens for 48 hours, with an evaluation of the eczematous lesions induced after 48 and 72 hours, according to the reading criteria of the European Task Force on Atopic Dermatitis (ETFAD). APTs show a higher specificity than skin prick and specific IgE tests, since the pathophysiological mechanism of the reaction induced is very similar to that which occurs in AD lesions. The standardization of APTs to aeroallergens has brought a certain reliability to this method, which is not the case for food APTs, in which the positive predictive value must be improved to avoid any unnecessary dietary restrictions. Thus, optimization of APTs and progress in the knowledge of the pathophysiology of eczemas could help to develop new immunobiological diagnostic methods and specific immunotherapy for AD.

Systemic allergic contact dermatitis to black cumin essential oil expressing as generalized erythema multiforme

ejd.2011.1351 Auteur(s) : Audrey Nosbaum audrey.nosbaum@chu-lyon.fr, Benoit Ben Said, Sarah-Jane Halpern, Jean-Francois Nicolas, Frederic Berard Allergy and Clinical Immunology Department, Centre Hospitalier Lyon-Sud, Hospices Civils de Lyon, 69495 Pierre Benite cedex, France The seeds of Nigella sativa, more commonly known as black cumin, contain 0.4%-2.4% essential oil [1]. In addition to the increasing scientific attention paid to its antioxidant and anticancer activities [2], black cumin [...]

Physiopathologie de l’urticaire et approches thérapeutiques

L’urticaire (nom féminin dérivé d’urtica ou ortie) est un synrome cutanéomuqueux inflammatoire très fréquent, puisque 12 à 0 % de la population présente au moins un épisode d’urticaire au ours de son existence. Il s’agit d’une éruption papuleuse, érythéateuse, prurigineuse et fugace (moins de 24 heures d’évolution our chaque lésion). L’urticaire peut être superficielle (œdème ermique) ou profonde (angio-œdème ou œdème du tissu sousutané) et disparaît sans laisser de cicatrice ni de pigmentation ésiduelle. Toute éruption qui ne rentre pas dans cette définition st dite « urticariforme » mais ce n’est pas a priori de l’urticaire. La cellule clé de l’urticaire est le mastocyte ; son rôle physioloique est d’établir une première ligne de défense sous-épithéliale ontre les microorganismes pathogènes et les parasites pénétrant ar cette voie. L’activation des mastocytes cutanés a schématiqueent trois conséquences (Fig. 1) : la dégranulation brutale avec

Systemic sclerosis and prevalence of monoclonal immunoglobulin.

INTRODUCTION The purpose of this study was to estimate the prevalence of monoclonal immunoglobulin (MIg) among patients with systemic sclerosis (SSc) according to the capillary electrophoresis or immunofixation method of detection and to search for any related clinical correlations. PATIENTS AND METHODS Retrospective multicenter comparison of capillary electrophoresis and immunofixation results in SSc patients and of the characteristics of patients with and without MIg. RESULTS The study included 244 SSc patients (216 women and 28 men, mean age: 55±14 years). Median time since SSc diagnosis was 51 months [0-320]; disease was diffuse in 48% of cases. Ten percent of patients had cancer, including Waldenström macroglobulinemia (n=1) and multiple myeloma (n=3). Capillary electrophoresis showed a γ-globulin anomaly in 41% of cases, and immunofixation in 18%: MIg (13.5%) and restriction of heterogeneity (4.5%). Capillary electrophoresis failed to detect 60% of the 33 MIg patients. Measurable MIg concentrations were obtained from 7 patients. MIg patients were significantly older at SSc diagnosis than those without MIg (p=0.002), had a lower diffusing capacity (p=0.002), a higher prevalence of pulmonary hypertension and cancer (p=0.002) and were more frequently positive for anti-mitochondrial and anti-beta2-glycoprotein-I antibodies (p=0.03 and p=0.02, respectively). Multivariate analyses showed that only age at test [hazard ratio 1.03 (95% CI, 1.00-1.07, p=0.04)] and presence of cancer [hazard ratio 4.46 (95% CI, 1.6-12.4, p=0.004)] were associated with MIg. CONCLUSION Immunofixation detected a high prevalence of MIg among SSc patients especially in patients aged 50-years or older. MIg was not detected by the standard capillary electrophoresis in 60% of cases and was significantly associated with cancer.

Corticosteroids should not be used in urticaria because of the potential risk of steroid dependence and development of severe anti-H1- resistant urticaria

ejd.2011.1311 Auteur(s) : Frederic AUGEY frederic.augey@chu-lyon.fr, Audrey NOSBAUM, Frederic BERARD, Jean-Francois NICOLAS Allergology and Clinical Immunology, CH Lyon-Sud, F-69495 Pierre-Benite Cedex, France Corticosteroids are widely used to treat urticaria and several inflammatory and autoimmune diseases. Steroid dependence is a well-known phenomenon. Corticosteroids are supposed to have a more constant impact on itching and swelling than anti-histamines (anti-H1), although neither topical [...]

The basophil activation test: a sensitive test in the diagnosis of allergic immediate hypersensitivity to pristinamycin.

Immediate hypersensitivity (IHS) reactions to macrolides and to macrolide-derived antibiotics like pristinamycin are uncommon. In this context, there is little data available to appreciate the true value of biological tools regarding the diagnosis of immediate allergy to pristinamycin. Here we assess the clinical usefulness of the basophil activation test (BAT) to differentiate allergic from nonallergic IHS to pristinamycin. Thirty-six patients were tested with skin tests as the gold standard and BAT. The BAT achieved a sensitivity of 76% and a specificity of 100%, implying an absence of false positive results. Multicenter studies remain to be performed to better define the sensitivity, specificity and interlaboratory variation of BAT in the diagnosis of allergy to pristinamycin and macrolides.

Atopy Patch Tests

Patch tests are used for diagnosing delayed hypersensitivity allergic reactions, like allergic contact dermatitis (ACD). More recently, atopy patch tests (APT) have been developed with aeroallergens and food allergens to diagnose delayed allergic outbreaks of atopic dermatitis (AD). In fact, exposure of patients suffering from AD to aeroallergens (house dust mites, cat dander, grass pollens) or food allergens can provoke an exacerbation or prolongation of the disease. Prick tests and specific IgE can be useful for detecting aggravating factors, but their precise implication in the genesis of the skin lesions should be controlled by carrying out APT, which are more adapted to the pathophysiology of AD.