Allergie et immunologie最新文献

Allergy to pseusoephedrine seems to be rare and has been described as responsible of urticaria, contact dermatitis, fixed non-pigmenting erythema or pseudoscarlatina. We report the case of a male patient who presented a recurrent erythema after administration of different treatments including pseudoephedrine. A cutaneous biopsy was compatible with erythema multiform. Patch tests confirmed the diagnosis of allergy to pseudoephedrine but resulted in a reappearance of symptoms.

Anisakis simplex is a nematode which infects marine fish. It requires marine mammals for its development. The larvae are found in fishes, crustaceans and cephalopods which are intermediate hosts. The parasite can be ingested by man -mainly with raw fishes- and induces an infestation called anisakiasis or anisakidosis with digestive tract symptoms. Since 1990, we have known that the parasite can also induce allergic symptoms such urticaria.

Cold urticaria is characterized by the development of urticaria, usually superficial and/or angioedematous reaction after cold contact. It was found predominantly in young women. The diagnosis is based on the history and ice cube test. Patients with a negative ice cube test may have represented systemic cold urticaria (atypical acquired cold urticaria) induced by general body cooling. The pathogenesis is poorly understood. Cold urticaria can be classified into acquired and familial disorders, with an autosomal dominant inheritance. Idiopathic cold urticaria is most common type but the research of a cryopathy is necessary. Therapy is often difficult. It is essential that the patient be warned of the dangers of swimming in cold water because systemic hypotension can occur. H1 antihistamines can be used for treatment of cold urticaria but the clinical responses are highly variable. The combination with an H2 antagonists is more effective. Doxepin may be useful in the treatment. Leukotriene receptor antagonists may be a novel, promising drug entity. In patients who do not respond to previous treatments, induction of cold tolerance may be tried.

Immuno-allergology of iodine contrast products is much discussed, the main questions posed by these molecules particularly concern the existence of specific IgE and their frequency, the specificity of the antibodies, involvement of the iodine atoms and their routes of sensitisation. Our preliminary study on 6 cases of urticaria (5) and erythema (1) after use of ioxaglate and with positive search for ioxaglate-specific IgE (2.3 to 6.7) after coupling to Sepharose (Baldo and Fisher technique). The results of this technique are expressed with reference to a pool of serum of subjects who had no contact with these contrast products. The threshold of positivity was 2, the mean of the results from 10 subjects who were exposed lay between 1.37 +/- 0.42. Inhibition of specific IgE by ioxaglate was positive in 6 cases. In 2/3 cases inhibition by potassium iodide was also observed. Several published studies in favour of the existence of specific IgE of close specificity, the inhibitions of specific IgE presented were mostly only observed for the contrast product used. An hypothesis would be that the ionic molecules have a greater capacity to induce the synthesis of specific IgE than non-ionic molecules because of their affinity for carrier proteins. The inhibitions seen with mineral iodine in this short study do not permit total elimination of the participation of the iodine atom at the antigenic site.

The diagnosis of food allergies (FA) relies upon the sequential use of different means and tools, according to a decision tree. Ten clinical characteristics point to a potential FA. A diary for food consumption during a week surveys all labellings, in order to detect masked food allergens. The second step is based on skin prick tests to natural foods, and epicutaneous tests to a few proteins (casein, gluten...). Biological tests using multi detection tests of specific IgEs to numerous allergens are not advised owing to the frequency of clinically not relevant in vitro cross-reactivity. Single determination of specific IgEs, have a 95% predictive positive value of high levels in cases of allergy to milk, egg, fish and peanut, and can spare oral challenges. The primary use of biological tests is not currently advised but may be of interest in litigious cases. Standardized oral challenges are the golden standard. Eviction regimens are an alternative used for cow's milk allergy in infancy, or for suspected digestive allergies in adults.

IgE-dependent allergy to muscle relaxants (MR) has an estimated prevalence of 1 out of 6500 General Anesthesias (GA). 62% of anaphylaxis during surgery are due to MR anaphylaxis. All the molecules are divalent, carrying two NH4+ epitopes (quaternary ammonium ions), either structurally or after rapid in vivo protonization (vecuronium). The excellent overall performance of skin test makes them the golden standard for the diagnosis of anaphylactoid reactions. Techniques include intradermal tests and prick-tests. The current localizations are the forearm and the back. Positivity criteria are 3 mm for prick-tests. For IDTs, the criterium is the doubling of the size of the injection papula, when 0.02 to 0.04 ml is injected: 8 mm. The recommended concentrations are not falsely negative. Commercial concentrations can be tested by prick tests, except for mivacurium and atracurium tested of 1:10 dilution. A scale of concentrations is advised for IDT starting with 1:10,000, up to a normally non reactive concentration that is: 100 micrograms/ml (succinylcholine), 200 micrograms/ml (gallamine), 10 micrograms/ml (atracurium), 2 micrograms/ml (mivacurium), 200 micrograms/ml (pancuronium), 400 micrograms/ml (vecuronium), 1,000 micrograms/ml (rocuronium), 200 micrograms/ml (cis atracurium). The specificity and sensitivity of the skin tests to MRs are greater than 95%. The reproducibility over years is 88%. The overall concordance of PT and IDR is 97%. Both types of tests can be used for the diagnosis. IDT have to be carried out for the search of the cross sensitization. 84% of patients do have cross sensitization to MRs but only 16% react to all MRs. The further use of MRs selected by negative IDTs has been proved to be safe.

Products of the sea are important source of food. Increase in consumption, due to their nutritive value has also led to a great frequency of reactions, including those that are immunologically mediated. Although hypersensitivity reactions to sea products are often easy to identify and can be confirmed by specific in vitro and in vivo tests, some patients can only be diagnosed by double-blind provocation test against placebo (DBPCFC). An atypical or incomplete clinical history suggests, always, contamination with toxins and/or parasites such as Anisakis. Crossed reactivity between different sea products is frequent. However, there are clinical differences between allergy to molluscs, crustaceans and fishes. From precise evaluation of the reactions to sea produce, will result a reduced and reasoned suppression from this type of allergens at food levels.

Diagnosis of allergy diseases is at first linked to a detailed history, in which professional activities as well as the environment take an important place. Fishing activity as well as aquarium-related activities may be the origin of a symptomatology which is, often IgE-mediated, respiratory and skin localised: the responsible agents are most often insects in their larval form, crustaceans and worms.

6% of infants are allergic to egg. 50% of them are at risk of becoming sensitive to pneumoallergens and of whom 50% develop asthma. These evolutionary risks which are the allergy "course" of the child may be avoided by a precise interrogation which is orientated towards detection by in vitro tests of F x 5 for foods and Phadiatop for pneumoallergens. The responsible allergens may themselves be shown by skin tests, measurement of specific IgE by CAP-RAST made by UNICAP.