Dermatite de contact aux protéines animales due aux allergènes du chat

Contact dermatitis to animal proteins is a dermatosis that presents as chronic eczema with episodic acute exacerbations usually located on the hands and forearms. It has been described especially as a result of repeated occupational contact with livestock and foods of animal origin. The present case report describes a patient with no occupational exposure to animals but who reported regular manual contact with a cat for a few weeks before developing hand dermatitis with severe itching. The lesions did not improve with a variety of treatments, including local corticosteroids. A diagnosis of chronic hand dermatitis caused by contact with cat epithelium was suspected and confirmed by positive skin prick tests and specific IgE assay. The patient was free of symptoms when separated from his cat during a period of three weeks. A positive provocation test with a cat confirmed the diagnosis. This is the first case report of non-occupational contact dermatitis due to cat epithelium.     

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.     

La marche de l'allergie : que reste-t-il de l'histoire dite naturelle de l'allergie ?

Until recently, it was generally agreed that the natural history of allergy overlapped with that of asthma. The dominant concept was that allergy, in particular, allergy to perennial aeroallergens, was the most important cause of asthma. The classical curves of the age-related incidence of the main allergic syndromes, i.e. those closely associated with asthma, made it appear that the first step in the natural history of atopy was atopic dermatitis, followed by asthma and rhinitis. Allergy to one or more foods, especially cow milk and egg, began early in life, very often disappeared, leaving place for the development of sensitivity to aeroallergens. This classic schema allowed one to suppose that primary prevention was possible and that by avoiding the main allergens very early in life one could reduce the subsequent risk of allergic sensitization and, therefore, of asthma as well. The interest in prevention was explained by the growing prevalence of allergic diseases, which had become an important public health problem. In fact, the natural history of asthma and allergy is much more complex, being a real puzzle in which one must take into account the allergens, life style (rural or urban), contact with animals, endotoxins, parasites, atmospheric pollution (e.g. the association between diesel particles and pollen), hygiene, infections and immunizations, breast feeding, pasteurized or non-pasteurized cow milk, the diet and many other factors. The aim of this critical review is to try to untangle this maze.     

Sensibilisation parentérale du lapin aux protéines du lait de vache : effets sur la perméabilité intestinale

Objectives

Study of the cow's milk protein intolerance mechanisms in order to knowledge, in which could proportions spread the permeability of intestinal to the β-lactoglobulin and α-lactalbumin at the rabbits sensitized to these two proteins.

Methods

The rabbits were sensitized to these proteins by subcutaneous way and their degree of immunization established by Elisa dosage of the specific IgG. For the study of the transepithelial exchanges, the interaction of the proteins (marked to the ¹⁴C-formol), with the mucous intestinal of sensitized and some control rabbits were follow-up in vitro on fragments of ileums mounted in Ussing chamber. Their transepithelial fluxes were measured, after stimulation by the proteins deposed in the mucous compartment from a sampling made from serosa side.

Results

The animals sensitized present some titers in IgG anti β-lactoglobulin and anti α-lactalbumin, as well as some transepithelial fluxes, significantly more increased than control animals.

Conclusion

These results suggests that at the immunized animals, the interaction of the sensitizing protein with intestinal mucous caused some anomalies of hydroelectrolytic transport.     

Allergie aux protéines du lait de vache sans allergie associée au lait de brebis chez l'adulte

IgE-mediated milk protein allergy is common among infants and young children but it can also develop in adult life. People affected by cow milk protein allergy may often develop allergy to sheep or goat milk. Allergy to goat and sheep milk without allergy to cow milk seems exceptional. Here we report the case of a patient with an allergy to proteins derived from cow milk that first appeared in adulthood, with good tolerance to proteins derived from sheep milk. The results of skin prick tests and the measurement of specific IgEs (CAP-RAST and dot-blot) are in favor of multiple sensitization to different proteins from cow, goat and sheep milk, but with a strong and specific response to bovine caseins (α and κ-caseins).     

Sensibilisation parentérale du lapin aux protéines du lait de vache : effets sur les paramètres électrophysiologiques de l’intestin

Objectives

Study of the effect of cow's milk protein (β-lactoglobulin [β-LG] and α-lactalbumin [α-LA]) on the electrophysiological parameters of the intestine rabbits sensitized to these allergens, directly incriminated in the non immunologic allergy to cow's milk proteins and their systemic effects.

Methods

The interaction of the proteins (marked to the ¹⁴C-formol), with the mucous intestinal of parenteraly sensitized and some control rabbits, was followed-up in vitro on fragments of ileums mounted in Ussing chamber. The electrophysiological parameters which characterize the tissue to the basal state then in the time, in regular intervals, were measured after stimulation by the proteins deposed in the mucous compartment.

Results

The interaction of β-LG and α-LA with the intestinal mucous, significantly more increased among the sensitized than some control rabbits, is associated to a significant increase of the short circuit current and the difference of potential while the conductivity remain unchanged.

Conclusion

These results suggest that the interaction of the sensitizing protein with intestinal mucous caused anomalies of hydroelectrolytic transport at the immunized animals and establishes an interesting approach for the understanding of physiopathological mechanisms of the increased permeability at these proteins.     

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.     

Console de jeu : mode de transmission de l'allergie à l'arachide

The authors report the case of a child allergic to peanuts since he was one year old who, at the age of 9 years, developed angioedema after playing with his "Play Station". This device had been used previously by his uncle who had eaten peanuts at a family get-together. This observation illustrates a new way of transmitting food allergies and provides an opportunity to review the principal situations in which this allergy can be transmitted by proxy.     

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

Oral food challenges (OFC) have to be carefully interpreted. OFC prove the food allergy or persistent food allergy. OFC prove also the absence or the cure of food allergy. Objective and subjective signs are distinguished. Cutaneous and gastrointestinal symptoms are more frequent than respiratory or systemic symptoms. Delayed reactions, isolated or associated, have to be taken into account. In some cases, the OFC cannot be interpreted. Negative double-blind placebo-controlled food challenge must be confirmed by an open manner.     

Allergie aux anesthésiques

Allergic hypersensitivity reactions occurring during anaesthesia are a major cause of concern, since these reactions remain unpredictable and may be life-threatening for the patient. Neuromuscular blocking agents, latex and antibiotics are the three agents most frequently involved in these reactions. A systematic allergoanaesthetic screening after every peri-anaesthetic incident is clearly warranted, both to avoid the patient's having a reaction during any subsequent anaesthesia and to obtain additional epidemiological data that can be used to improve the future management of all anaesthesia procedures. This allergy screening includes standardized laboratory and skin test procedures, with verification of the concordance between the clinical history and the test results. Atopic infants and those having had multiple surgical interventions are at risk for allergic reactions to latex. In the case of children with spina-bifida, strict latex avoidance measures must be followed systematically, beginning with the first intervention.     

Allergie respiratoire aux protéines de feuilles, implication d’un nouvel allergène

Symptoms of subjects presenting with rhinitis, conjunctivitis or contact urticaria when exposed or in contact with grass are usually attributed to allergy to grass pollen or to certain airborne molds. The four cases described in the present report presented with allergic symptoms when mowing their lawn. The suspicion of allergy to grass leaves was confirmed by skin prick tests with native leaves. An extract of rye grass leaves was made and its allergens were analyzed by SDS-PAGE and immunoblotting. Three of the four patients were found to have IgE specific for a single 56 kDa molecule. It was shown to be a major leaf protein and identified as a subunit of ribulose 1,5 diphosphate carboxylase/oxydase, a major plant kingdom enzyme involved in photosynthesis. This protein is widely present in leaves and is, in addition, used as a non-allergenic model in investigation of the allergenicity of food proteins. In fact, it is degraded instantaneously by digestive enzymes, in contrast to the known principal food allergens. In conclusion, respiratory allergy to grass leaf proteins was demonstrated in this study of four patients, who were or were not allergic or sensitized to grass pollen.     

Sensibilisation aux médicaments topiques

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.     

Quoi de neuf en allergologie pédiatrique en 2005 ? Partie 4. Allergie cutanée,alimentaire, médicamenteuse et aux insectes (Une revue de la littérature internationale d'octobre 2004 à octobre 2005)

Allergological work-up and treatment of french children with atopic dermatitis have been the subject of a recent consensus. Food avoidance is useless for prevention of atopic dermatitis, and should be indicated in children with severe atopic dermatitis associated with food allergy only. Exposure, sensitization and allergy rates to nuts increase with age, and avoidance of nuts (even tolerated) is recommended in young children allergic to one or several nuts to prevent the risk of sensitization and allergy to an increasing number of nuts. Threshold values of skin prick-tests and specific IgE determinations with a 90-100% predictive value for food allergy are highly variable from one study to another one, and depend on numerous factors such as age of the children, the allergens used, etc. The diagnostic value of patch-tests and skin application food tests remains controversial. Treatment of food allergy is based on the eviction of the allergenic foods. However, probiotics and « desensitization » to foods may be efficacious in some patients. In children that have outgrown their food allergy, tolerance should be maintened by regular consumption of the foods. However, the parents should be informed that relapses requiring an emergency treatment may occur. Finallly, in children as in adults, repeated mosquito bites induce a desensitization, and most children outgrow their allergy between five to fourteen years.     

Allergologie et auto-immunité : médecine interne aux frontières de l'allergologie

At the crossroad of numerous medical specialties, Internal Medicine incorporates a number of different fields, including autoimmune diseases and other immunological conditions, the symptoms of which can simulate those of allergies, particularly allergies of the skin and lungs. We will limit our discussion to only a few aspects of this subject: 1) concerning immunological aspects, CD4+ IL17+ lymphocytes and the detection of autoantibodies in chronic urticaria; 2) concerning pharmacological aspects, discussion of the eventual role of acetaminophen in the recent increase in the frequency of asthma and allergic diseases; and 3) concerning other clinical matters, mastocytosis and insect stings, eosinophilic esophagitis, mosquito bites, allergy and NK lymphoma.     

Modèles animaux d’allergie alimentaire. Application aux protéines de blé

The allergens responsible for wheat food allergy are beginning to be characterized. Nevertheless, animal models that produce highly-specific IgE and clinical symptoms comparable to those observed in allergic patients are of great interest for precise studies of allergens and of the mechanisms involved in wheat allergy. The aim of our research was to develop, in the first instance, a mouse model of allergy to a total extract of gliadins, then to use this model to study two major wheat allergens involved in wheat food allergy on children and adults, namely, the lipid-transfer protein (LTP) and the omega-5 gliadins.

Methods

First, we determined the mouse strain and the allergen dose required to induce an optimal allergic reaction to wheat. Three strains of mice (Balb/cJ, B 10.A ND c3 h/hEj) received four successive intraperitoneal injections of a total-gliadin extract (10 or 20 μg) adsorbed on alum. The level of sensitization was determined by assay of gliadin-specific IgE and IgG1 and by the level of cytokines secreted by splenocytes activated in vivo by the gliadins; in vitro basophil (RBL) degranulation tests were also done. In addition, the intensity of the allergic reaction was evaluated in vivo by analysis of the production of type Th2 cytokines and the influx of eosinophils in bronchoalveolar fluid (BAF) after intranasal gliadin extract provocation. Sensitization assays and provocation tests with LTP and omega-5 gliadins were done subsequently.

Results

The highest level of sensitization was observed in the Balb/cJ mice, whatever the dose of gliadins used. After the provocation test, these mice developed an intense-allergic reaction, as demonstrated by the strong production of type Th2 cytokines and the influx of eosinophils in the BAF. In contrast, a weak or no reaction was observed in the other two mouse strains. While sensitization of Balb/cJ mice by omega-5 gliadins was not very effective, administration of LTP induced significant production of specific IgE and IgG1 as well as specific degranulation of RBL cells, but little or no secretion of type Th2 cytokines by activated splenocytes. Induction of an allergic response after intranasal introduction of LTP was not very effective, in spite of the cellular influx in the BAF.

Conclusion

Balb/cJ mice, sensitized by intraperitoneal injection of a total-gliadin extract, appeared to produce some of the markers of wheat allergy, but the results of the sensitization studies with the purified allergens appear to be more complex.     

Résultats de tests cutanés intradermiques sur un groupe de sujets contrôles avec le rocuronium et le cis-atracurium à la concentration de 1/10

To investigate the cause of a pre-operative adverse reaction, intradermal tests are the validated method used for the diagnosis of immediate allergic reactions to curares. The maximal concentrations to be injected are still under discussion. The aim of this study was, therefore, to show that tests done with 1/10 dilutions of rocuronium and cis-atracurium lead to false positive reactions. Twenty-six healthy volunteers were tested with rocuronium and 53 with cis-atracurium. Intradermal tests were done with concentrations of 1/10 (1 mg/ml and 0.1 mg/ml, respectively), the cutaneous responses being read 15-20 minutes later. A wheal with a diameter of at least twice the diameter of the wheal produced by the injection was considered positive. Our results showed a tendency toward nonspecific histamine liberation at the concentrations of the two myorelaxants used. Thus, we observed positive reactions in 11/26 (42%) of the rocuronium controls and 19/53 (36%) of the cis-atracurium controls. Our results support the present recommendations of the Société Française d’Anesthésie et de Réanimation concerning the dilutions to be used with rocuronium and cis-atracurium to avoid false positive skin tests. In screening for peri-operative allergy, the maximum concentration used in intradermal testing with these two curares should not exceed 1/100.     

Intolérances et allergies aux colorants et additifs

Intolerance to food colorants and additives remains a reality, well-known in adults but difficult to prove in children because of the load of the examinations that must be done. The incidence of adverse effects is certainly low in the general population, between 0.03 and 0.2% according to many reports, although it may be as high as 1% according to other reports. It is higher depending on the population studied, being, for example, up to 2% in atopic children. There are many pathophysiological mechanisms, depending on the nature of the responsible substance. An IgE-dependant mechanism dependant is present in the case of the carime in cochineal (E 120), carrageenan (E 407), guar gum (E 413), lysozyme (E 1105) and annatto. The published data on colorants, conservatives, taste screeners, antioxidants, texturants, enzymes, sweeteners, and aromas is reviewed. Diagnosis is based on evidence obtained from the clinical history, responses to questions dealing with eating habits, a provocation test, the effect of avoidance and on eventual reintroduction of the suspected substance.     

Comment tester les eczémas de contact aux cosmétiques ?

The diagnosis of allergic contact dermatitis to cosmetics is based on a careful history (anamnesis), taking into account all the cosmetic products that have been used by the patient, on inspection of the clinical symptoms and localisation of the lesions, and on the performance of epicutaneous tests or patch tests. In addition, other types of tests such as open and semi-open testing with products having a certain irritant potential as well as repeated open application tests (ROAT) on the forearm can also be very useful in the diagnosis of contact dermatitis caused by cosmetic products.     

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?).