Revue francaise d'allergologie et d'immunologie clinique最新文献

All asthma consensus statements recommend the use of a written action plan. Patients tend to have a positive perception regarding the use of action plans for asthma. They find that action plans are useful for the management of their asthma. Nevertheless, an action plan should not be viewed as the only element in self-management strategy. It is usually part of a multifaceted intervention, including therapeutic education sessions, medical review and prescription of medications. A recent meta-analysis reported a positive effect of the use of written action plans. It is agreed that a written action plan should be tailored to each individual patient and to the type and severity of his asthma. Still, the precise elements of action plans that are responsible for their benefit have not yet been clearly identified. However, considering the different action plans that have been published, it would appear reasonable to build on prior experience and adopt a three-step approach, such as a sequence of stoplight colours, as a means to compare one action plan with others.

Immunotherapy trials on food allergy were published some years ago and few of them were randomized. The protocols used varied and IgE-mediated food allergies were the first studied. Immunotherapy is mainly indicated for persistent food allergy after the usual age of recovery. Other factors, such as the dose of the allergen and the nature of the symptoms due to food allergy, are less well-defined with regard to indications for immunotherapy. Different techniques are available: the subcutaneous route, with well-known adverse effects when currently available extracts are used; the oral route, with efficacy in a third of the cases and the sublingual route, which seems to be promising. The real effect of immunotherapy, whether persistent, transitory or merely an increase in the amount of food tolerated, remains to be defined.

Two important parameters control skin sensitization to a xenobiotic molecule: its sensitizing potential, an intrinsic property of each chemical, and exposure. It is often difficult to quantify a patient's exposure to a given allergen, which makes it difficult to define strong allergens. Indeed, the prevalence of an allergen, as determined by patch testing, reflects not its strength but a combination of sensitizing potential and exposure. The definition of strong sensitizers is therefore mainly derived from animal experiments where it is possible to assess a sensitization threshold or the dose per square centimeter that is able to induce significant sensitization. It has been shown in a limited number of case studies, that there is a good correlation between sensitization thresholds assessed in mice by the Local Lymph Node Assay (LLNA) and those obtained in humans with the Human Repeated Insult Patch Test (HRIPT). Based on this classification, one can recognize that strong sensitizers are quite common and that the general population is exposed regularly to them. Although the strong sensitizers include a broad diversity of chemicals, they have in common the ability to rapidly modify nucleophilic residues of proteins.

Some skin diseases require emergency medical intervention when they are life-threatening or when the eruption is spectacular and brutal and the patient has an elevated temperature. We will discuss the clinical presentations of these conditions, excluding cutaneous drugs eruptions. Patients with severe atopic dermatitis may require brief hospitalisation if their eczema is generalized, refractory to classical therapy, or there are infectious complications, as in the Kaposi-Juliusberg syndrome when the condition is associated with a secondary herpetic infection. Acute urticaria and angioedema are frequent causes of emergency room-visits. They can be the result of drug allergy, food allergy, allergy to stinging insects or contact urticaria. However, the cause is not always identified, even after a complete allergy work-up. Some cases of contact eczema are spectacular, in particular when the face is severely oedematous. Paraphenylenediamine, topical corticosteroids and topical non-steroidal anti-inflammatory drugs are often the cause of severe delayed-type hypersensitivity reactions.

Insects can be found in any areas in the world, so that it will be practically impossible to avoid them in a journey. They are the cause of many different pathologies, minor at large, but potentially severe sometimes, because a large number of them are part of epidemiological cycles, and are likely to transmit different pathogenic agents. A journey, especially in tropical areas, will have to be prepared so as to clarify the measures vital to take (vaccines, precautions of hygiene, protection equipment, preventive medicines…). Nowadays it represents a serious problem, considering the constant increase in world-wide tourism and trades.

To date, neither in vitro nor in vivo tests can establish with reliability the diagnosis of food allergy. The availability of recombinant allergens (RA) has led to improvement in the standardization of allergenic extracts and enrichment of natural extracts, resulting in more sensitive screening tests. These biotechnological advances facilitate the diagnostic approach which now rests on an individual reaction profile (component resolved diagnosis) with well-characterized allergens classified on a molecular basis. Development of diagnostic tests using RA or peptides expressing some distinctive epitopes of interest may improve the prediction of severe and/or persistent food allergies and guide the choice of the therapeutic measures that follow.

Atopic dermatitis (AD) is by definition a chronic pruritic skin disease characterised by a history of flares and remissions. Genetic studies have recently demonstrated a link of causality between an impaired permeability barrier defect and both AD and mucosal allergic disorders, putting the skin stratum corneum at the centre of the pathophysiology of these disorders. The respective importance of flare factors is difficult to sort out in published papers. Some of them, such as temperature, irritants and aeroallergens have a demonstrated impact on the permeability barrier anomaly, based on epidemiological or experimental evidence. However, a better methodology and terminology are needed to identify the most significant flare factors and promote an efficient prevention.

The information provided by pollen counts cannot be ignored by allergists and allergic individuals, but the divergence sometimes observed with clinical observations has led the réseau national de la surveillance aérobiologique (RNSA) to initiate the monitoring network of allergens by immunosampling (Monalisa) project. Moreover, some recent papers has shown the influence of pollution in the region and even of the year on the content in pollen allergens, particularly that of birch pollen. Thus, the goal of the Monalisa project was to set up a measuring system based on an immunological method that would result in validation of this new way of measuring airborne pollen counts. This European Life Environment project includes nine partners: Bertin Technologies (France), RNSA (France), NPARU (England), UCO (Spain), UTU (Finland), UAM (Poland), UEVORA (Portugal), AIA (Italy), and Meteoswiss (Switzerland). The results obtained during the 2006 season and then in the 2007 campaign, after modifications made in the sampler, were not very good. The principal results concern the measurement of birch and olive allergens, captured essentially in the prepollination period and sometimes in the postpollination period. Detection of these allergens may be due either to their presence on submicroscopic particles emitted independently of pollination, these allergens cross-reacting with birch and olive allergens. The difficulties encountered in this study lead us to say that pollen counts, phenological observations and clinical data are still the best way to assess the effects of airborne pollen.

The role of allergens as a trigger for bronchial symptoms has always appeared to be deeply linked to their ability to get into the respiratory tract. Interest in large diameter particles has focussed essentially on their capacity to reach the lower airways. The recent demonstration of the effect of aerosols of allergen-loaded pollen particles of a respirable size supports this hypothesis. Nevertheless, the exact site of allergen deposition leading to asthma symptoms is still not known. Studies carried out with allergen bronchial challenge tests using particles of different sizes have lead to a better understanding of the associated pathophysiological phenomena. Thus, the role of large-diameter particles could be more important than previously thought. Indeed, the results obtained provide support for the importance of these particles and their proximal deposition in the immediate bronchial response.

Occupational skin diseases of chemical origin are frequent among hairdressers. They can be caused by hair dyes, in particular those containing para-amines (especially paraphenylenediamine); bleaching agents containing alkaline persulphates, which can cause eczema, contact urticaria, rhinitis and asthma; liquids used in permanents containing products derived from irritant, sensitizing glycolic acid; irritant and sensitizing shampoos, in particular those with coconut derivatives, proteins hydrolysates and ubiquitous perfumes. Other allergic factors which are observed episodically include nickel, glutaraldehyde, formaldehyde, ethyl cyanoacrylate and minoxidil (Regaine^®). Prevention, which is essential, should start at the beginning of the training.