Seuil minimal de réactivité au cours des tests de provocation orale

Determination of the threshold dose for clinical reactivity for a given food is done as a function of certain criteria. For example, the patient must not be aware of the minimal reactivity dose; it should be noted that this dose might vary from time to time. In addition, the food production industry, being concerned with safety issues, would like to know the minimal reactivity dose for specific foods. Currently available data indicate that this dose can be less than 1 mg and, furthermore, that it is difficult to determine with precision.     

Détermination des seuils de réactivité au cours des allergies alimentaires

It is important for an individual allergic to food to be aware of the threshold (the minimal amount) of the allergenic food that can trigger a reaction. This information is equally essential to the food-processing industry for labeling of pre-packaged foodstuffs. Three methods are available to determine the threshold: case reports, statistical methods and oral provocation tests. Published data available at present allow only limited analysis for three foods (cow milk, chicken egg and peanut). In addition, the absence of standardized oral provocation tests limits determination of thresholds.     

Un cas une revue : syndromes coronariens aigus avec sus-décalage du segment ST à coronaire « coupable » angiographiquement saine

Acute coronary syndrome results in most cases of atherosclerotic plaque rupture. In a few cases, the physiopathological mechanism is different. This does not necessarily change the initial strategy but the subsequent treatments. We report three cases of clinical presentations of acute coronary syndrome whose pathophysiological mechanism is not or not mainly due to atherosclerotic lesions. Based on these cases and a review of the literature, two topics will be tackled: the diagnostic and therapeutic strategy in the management of Tako-tsubo cardiomyopathies and also acute coronary syndromes due to vasospastic angina.     

Test de provocation par voie orale aux aliments chez l'enfant. Quand,pour qui et comment ? Conséquences

Whatever results are, oral food challenges (OFC) will have consequences, particularly on diet and emergency kit. Positive OFC, negative OFC and food specificities are discussed, according to the literature review. In case of positive OFC, the management and monitoring of persistent food allergy is specified. Practical recommendations are suggested.     

Exploration des conjonctivites allergiques : comment explorer ?

The management of allergic conjunctivitis requires a specific approach, which can be divided into three particular schemes: (1) faced with a benign acute seasonal or chronic conjunctivitis, the workup should include skin prick-tests and assays for specific IgE antibodies. The allergens to use and the criteria for a positive reaction should be adapted to the condition of the ocular surface. When not clinically evident, the pertinence of the tests to be used will depend on the results of conjunctival provocation tests; they can be done on an ambulatory basis ; (2) contact allergy should be suspected in another context, that is, when the patient is older and the lesion looks more like blepharitis than conjunctivitis. Patch tests or open testing can detect many allergies, such as eye drop additives, various cosmetics and occupational allergens ; (3) when confronted with vernal or atopic kerato-conjunctivitis, arguments in favour of an allergy of the ocular surface may be obtained by comparing results of lachrymal and blood assays (eosinophils, ECP, total IgE). When sensitization is obvious, conjunctival allergen challenge is indicated with the suspected allergen in a specialized clinic. Then specific allergic treatment can be evaluated.     

Devenir des allergènes dans l’arbre respiratoire

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.     

Choc anaphylactique à l'Augmentin chez une patiente présentant des tests cutanés et un test de provocation négatifs à l'amoxicilline

Mme M. was seen in consultation with a history of possible allergy to penicillin. The patient reported that three months earlier she had experienced the sudden onset of a generalized but not very severe urticarial reaction, which included swelling of the face, beginning four days after taking amoxicillin, but not any other medication. She was not aware of any previous reaction associated with taking any drug, including penicillin. Skin tests with major and minor penicillin determinants, and then with amoxicillin, up to a concentration of 20 mg/ml intradermally were negative. It was then elected to do an oral provocation test with amoxicillin. She tolerated a single 1 g oral dose perfectly well. Eighteen months later, she was seen again following an episode of anaphylactic shock that had begun immediately after taking 1 g of amoxicillin associated with clavulanic acid (Augmentin^®). Between the two consultations, the patient had received no betalactamines, whereas she had tolerated two courses of treatment with macrolides. At the second consultation, skin tests with penicilloyl-polylysine and amoxicillin were definitely positive. This observation suggests two hypotheses, which are not however mutually exclusive: 1) The low predictive value of skin and provocation tests in patients weakly sensitized (Could such patients continue treatment with amoxicillin for several more days?); 2) the possibility that an initially weak sensitization was potentiated by the skin and provocation tests (Is it advisable to systematically do a second allergy workup several weeks after the first one to exclude the possibility of sensitization in this type of patient?).     

Dermatite atopique et allergie alimentaire chez l'enfant

Food allergy is known to provoke flares of atopic dermatitis (AD). The prevalence of food allergy in infants with atopic dermatis has been estimated to be 40%. Atopy patch testing is a novel approach to diagnose food-induced AD, but standardization of atopy patch test extracts needs addional studies. Oral food challenge is the gold standard for diagnose of food allergy. Nevertheless, the method used for oral food challenges in cases of late eczematous reactions remains to be defined. Food appears to aggrevate eczematous lesions in young children, and it is recognized that allergy testing needs to be standardized in order to prove that relationship.     

Aproximación al diagnóstico y tratamiento de la anemia crónica secundaria a causas digestivas

Iron deficiency anemia is the most common type of anemia and can cause asthenia, cognitive and functional impairment, and decompensation of underlying diseases. Iron deficiency anemia is not a disease but is the result of a potentially serious medical problem. Consequently, patients should always undergo investigation of the underlying cause. In men and postmenopausal women, the condition is caused by gastrointestinal loss and malabsorption of iron. In this group, recommended procedures are gastroscopy, colonoscopy and serological testing for celiac disease. If the results of these tests are negative, repeat examinations and iron therapy should be considered. In treatment-refractory or recurrent anemia, the small intestine should be investigated. In this case, the procedure of choice is capsule endoscopy. Iron deficiency anemia should always be treated until iron deposits have returned to normal levels. A wide variety of preparations are available, in both oral and parental formulations.     

Allergie aux corticostéroïdes

Corticosteroids are widely used for their anti-inflammatory and immunosuppressive properties in the treatment of respiratory, allergic and autoimmune diseases. Their adverse effects are well known, but allergic reactions to these drugs are relatively rare although they are sometimes severe. While the route of administration was different in the two cases reported here - one oral, the other by inhalation - the adverse reactions began soon after administration and presented the same symptoms, namely, cough, dyspnea and wheezing. Skin tests and/or provocation tests are essential to confirm the diagnosis. They require tests with different groups of molecules. For our young asthmatic patient, the results were positive for only one group of corticosteroids, which allowed us to prescribe an alternative treatment.