Allergy to hazelnut in adults: A two-step study

BackgroundAlthough hazelnut consumption is very high in Turkey, the prevalence of hazelnut allergy is still unknown. This study's objective was to investigate the prevalence of hazelnut sensitisation and to verify its clinical importance using double-blind, placebo-controlled challenge (DBPCFC) in an adult population.MethodsPrick-to-prick skin tests were performed with fresh hazelnut in 904 patients admitted to the allergy department. Among the 904 subjects, 20 patients with a history of allergic reactions to hazelnut and/or positive skin tests were recalled for further evaluation. Specific IgE was measured in these subjects. Eleven (11/20) patients accepted to undergo DBPCFC with hazelnut.ResultsAmong the 904 individuals, the history of reactions to hazelnut was positive in 16 subjects (1.8%); prick-to-prick skin tests were positive in 13 (1.4%); prick tests with the commercial product were positive in nine (0.9%); and history plus skin tests were positive in 16 (1.8%). Specific IgE to hazelnut was positive in only three patients. DBPCFC was conducted in 11 subjects with a positivity rate of 63.6% (7/11). We observed six mild and one moderate systemic reactions during the DBPCFC. Among seven subjects with a positive DBPCFC, six (85.7%) had a history of hazelnut allergy, and five (71.4%) had both history and skin test positivity.ConclusionSkin test sensitisation to hazelnut was found to be 1.76% (16/904) which is similar to the sensitisation rate in previous reports. However, DBPCFC was positive in 63% of cases with a history of hazelnut allergy and/or positive skin tests in this study. These results indicate that the presence of history with a positive skin test can be suggestive of hazelnut allergy; however an oral food challenge is needed to confirm the diagnosis.     

Sensitivity and specificity of food specific IgE and IgG determinations for the diagnosis of food allergy

Among the methods currently used to demonstrate a sensitization to foods, the measurement of food specific IgE antibodies (sIgE) is the most practical but not the most accurate. The "sensitivity" of food sIgE determinations is, for example, suboptimal with unstable allergens in fruits and vegetables that are involved in the (birch) pollen-related immediate oral allergy syndromes. In this particular syndrome the history is often conclusive and can be substantiated by skin prick tests with fresh foods. The "sensitivity" of sIgE tests is much better when sIgE are directed to stable plant or animal food allergens which often cause non-immediate generalized reactions. Foods, usually, contain many different (glyco)proteinic allergens of which some are stable and others not. The "sensitivity" of the sIgE test with a particular food, therefore, varies according to the type of allergen that is recognized by the patient. The "specificity" of sIgE tests with foods is affected by the existence of homologous food allergens which induce cross-reactive IgE that may or may not be clinically relevant. While variable, clinical cross-reactivity is more common among botanically-related fruits, among different nuts, among mammalian foods and among seafood than among cereals, grains and legumes. The "specificity" of food sIgE tests is much better when sIgE are directed to unique non-cross-reactive food allergens. Unfortunately, neither the presence of food sIgE nor its level are predictive of clinical reactivity. The identification of individual allergens in foods and the characterization of the relevant IgE binding sites in these allergens might lead to the development of tests that only measure sIgE to clinical relevant food allergens.     

Study of the in vitro sulphidoleukotriene production in food-allergic patients.

OBJECTIVE AND DESIGN: To study in vitro sulphidoleukotriene (sLT) production by food allergic patients using cellular allergen stimulation test (CAST)-ELISA and to evaluate the reliability of this technique for diagnosing food allergic reactions. SUBJECTS: Forty patients with adverse reactions after food intake, 20 healthy controls, and 15 individuals sensitized to inhalant allergens as atopic controls. METHODS: Skin tests, serum-specific IgE, histamine release test (HRT), CAST-ELISA and food challenges. One-way ANOVA was used to compare tests results between patients and controls and to study mediator release and specific IgE, related to the severity of clinical pictures. Sensitivity and specificity were analyzed by ROC curves. RESULTS: Food allergic patients showed higher (p < 0.05) Ag-dependent sLT production (836.2 +/- 664.1 pg/ml) (mean +/- standard deviation) than both control groups. After stimulus with anti-IgE antibodies, sLT production was higher (p < 0.05) by atopic controls (1630.8 +/- 696.5 pg/ml) compared to patients and healthy controls. Patients with anaphylactic reactions showed higher Ag-specific and anti-IgE sLT and histamine production than patients with less severe manifestations. Mean serum-specific IgE was significantly lower (p < 0.05) in patients presenting oral allergy syndrome compared to patients with more severe clinical pictures. CAST-ELISA was the most sensitive method. Prick by prick test was the most specific. CONCLUSIONS: CAST-ELISA may provide a useful tool for diagnosing food allergy. Enhanced cell releasability may be linked to the severity of the clinical response to foods.     

Double blind, placebo controlled food reactions do not correlate to IgE allergy in the diagnosis of staple food related gastrointestinal symptoms.

BACKGROUND: The mechanisms for adverse reactions to foods in the gastrointestinal tract are poorly understood. There is conflicting evidence in the literature on the role for IgE mediated allergy in gastrointestinal reactions to staple foods. AIM: The aim was therefore to study the role of IgE mediated allergy in a group of patients with a history of gastrointestinal symptoms related to staple foods (cows' milk, hens' egg, wheat and rye flour) verified in double blind placebo controlled challenges (DBPCFC). PATIENTS: Fifteen patients with DBPCFC, identified by screening of 96 consecutive patients referred to our allergy clinic for investigation of suspected gastrointestinal symptoms due to staple foods. METHODS: The screening included diaries as well as elimination diets and open and blinded food challenges. The frequency of atopy were compared between the double blind positive and double blind negative patients. RESULTS: The positive DBPCFC in the 15 patients included eight patients with milk intolerance, four with wheat flour, two with egg, and one with rye flour. There was no indications of an allergic pathogenesis in all 15 patients with positive DBPCFC, as the skin prick test and radioallergosorbent test were negative for the relevant allergens. The frequency of atopy was four of 21 (19%) in the double blind negative group and three of 15 (20%) in the double blind positive group. CONCLUSION: In adult patients with staple food induced gastrointestinal symptoms, objectively verified by DBPCFC, there were no indications of IgE mediated allergy to the relevant foods suggesting other mechanisms in adults than in children. Future studies may include measures of local events in the shock organs in relation to food intake, for instance utilising inflammatory markers in jejunal fluids.     

Occupational asthma due to carrot in a cook

BackgroundFew previous reports of carrot-induced asthma have been confirmed by objective tests. Hypersensitivity to carrot is frequently associated with allergy to Apiaceae spices and sensitization to birch and mugwort pollens.Clinical caseA 40-year-old cook woman was seen with sneezing, rhinorrhea, contact urticaria and wheezing within few minutes of handling or cutting raw carrots. She needed to leave out of the kitchen while the other cooks cut raw carrots.Methods and resultsSkin tests were positive to carrot, celery, aniseed and fennel. Rubbing test with fresh carrot was positive. Specific IgE to carrot was 4.44 kU/L. Determinations of specific IgE to mugwort, grass and birch pollens were negative. Inhalative provocation test, performed as a handling test, was positive. The IgE-immunoblotting showed two bands in carrot extract: a band with apparent molecular weight of 30 kd and other band of 18 kd. This band of 18 kd was Dau c 1. The band of 30 kd could correspond a phenylcoumaran benzylic ether reductase.Dau c 1 did not appear to be the unique allergen in this case. Additional allergens may induce the sensitization. Primary sensitization due to airborne allergens of foods and the lack of pollen allergy in this patient are notorious events.     

Food allergies associated with birch pollen: comparison of Allergodip and Pharmacia CAP for detection of specific IgE antibodies to birch pollen related foods.

Sera from 42 patients sensitive to birch pollen were investigated in a pilot study with the new Allergodip screening dipstick for cross-reactive allergens (Allergopharma). The dipstick contained nine separate allergen pads with extracts from birch pollen, hazel pollen, alder pollen, apple, hazelnut, carrot, peach, mugwort pollen and celery root (celeriac), together with negative and positive controls. The results of the test were assessed visually and classified in Allergodip classes 0-4 and compared with the results from the Pharmacia CAP method and with the symptoms reported by the patients. The Allergodip method showed good reproducibility for color intensity and visual assessment. The correspondence between Pharmacia CAP and Allergodip was high for tree pollens (98-100%) and medium for mugwort pollen, celery, hazelnut and carrot (60-71%). Apple and peach showed only 24% and 42% concordance, respectively The sensitivity and specificity of Allergodip and Pharmacia CAP differed in regard to food symptoms. However, they were always within the range of earlier publications. As a consequence of this study, the manufacturer of Allergodip has improved the apple allergen extract by adopting a low temperature extraction procedure. Subsequent measurements with sera from 14 apple-allergic patients showed greatly improved concordance with both CAP measurements and symptoms (93% and 86%, respectively).     

Vaccination with genetically engineered allergens prevents progression of allergic disease

IgE-mediated allergy affects >25% of the population in industrialized countries. Repeated contact with the disease-eliciting allergens induces rises of allergen-specific IgE Abs and progression of the disease to more severe manifestations. Our study uses a type of vaccine that is based on genetically modified allergen derivatives to treat allergic patients. We developed hypoallergenic derivatives of the major birch pollen allergen, Bet v 1, by genetic engineering and vaccinated birch pollen-allergic patients (n = 124) in a double-blind, placebo-controlled study. Active treatment induced protective IgG Abs that inhibited allergen-induced release of inflammatory mediators. We also observed a reduction of cutaneous sensitivity as well as an improvement of symptoms in actively treated patients. Most important, rises of allergen-specific IgE induced by seasonal birch pollen exposure were significantly reduced in vaccinated patients. Vaccination with genetically engineered allergen derivatives is a therapy for allergy that not only ameliorates allergic reactions but also reduces the IgE production underlying the disease.     

Egg and milk allergy in asthmatic children: assessment by immulite allergy food panel, skin prick tests and double-blind placebo-controlled food challenges

There is a perception that asthmatic symptoms may be worsoned by ingestion of certain foods. This study aimed to investigate whether ingestion of cow's milk or egg might induce respiratory symptoms in asthmatic children. Fifty asthmatic children aged 1.5 to 6 years old, with positive Immulite Food Panel FP5 test results were included in the study. Fifty healthy children within the same age group were accepted as control group. Total serum IgE levels were measured and skin prick tests for food allergens including milk and egg were performed. All of the subjects underwent oral, double-blind, placebo-controlled challenge with fresh egg and cow's milk powder. Two medical histories were confirmed by double-blind, placebo-controlled challenge in 9 patients (22.2%). Skin prick tests were positive in 9 patients (18%) with milk and 18 patients (36%) with egg antigen. Two children experienced wheezing, one after ingesting milk and the other after egg challenge (4%). In the control group no positive reactions were seen with egg or milk challenges. Our findings confirm that food allergy can elicit asthma in children, but its incidence is low, even with major allergens such as egg and milk. History, specific IgE determinations and skin prick tests are not reliable in diagnosing food reactions. Since any diet can cause rapid deficiencies in infancy, diet restrictions must not be applied, without performing double-blind, placebo-controlled challenge.     

花椒严重过敏反应及花椒致敏组分分析

目的总结15例花椒严重过敏反应患者的临床特点、点刺试验、特异性IgE结果,并对花椒致敏组分进行分析。方法采用统一问卷,收集所有花椒过敏反应患者的临床资料。用ImmunoCAP检测血清花椒籽和花椒皮特异性IgE。用Powerlook2100XL（UMAX）扫描和imageQuant TL软件分析花椒籽和花椒皮的SDS-PAGE蛋白电泳成分和免疫印迹结果。结果花椒过敏15例,男6例、女9例,就诊年龄28～59岁,均表现为速发型食物过敏反应,过敏反应均发生于进食过敏食物后30分钟内;14例诊断为严重过敏反应,其中5例曾发生过敏性休克（2例伴有意识丧失）,1例诊断为急性荨麻疹。14例起始症状为口咽部过敏反应。该组病例均伴有多种食物,如腰果、开心果、橘子、金桔、芝麻、杏仁、榛子、松子、芒果等过敏;15例均存在腰果和/或开心果过敏,但进食花生、黄豆均不过敏。食物过敏病程1～17年不等。10例过敏患者花椒籽点刺试验均为强阳性,2例为3＋、8例为4＋,2例出现全身反应,24小时内好转;花椒皮点刺试验1例为2＋,2例为＋,7例为-。3例健康对照者花椒皮和花椒籽点刺试验均为阴性。13例花椒过敏患者中,花椒籽特异性IgE,1例为2级,余12例均为3级以上;花椒皮特异性IgE,11例为0级,2例为2级。花椒籽与花椒皮特异性IgE比较,差异有显著性意义（P〈0.00014）。花椒籽和花椒皮致敏组分蛋白免疫印记结果显示,7例患者中1例相对分子质量为11400～12400,3例为11400,1例为11300,1例为11400～12500,1例无结合条带。结论进食少量花椒即可能诱发严重的过敏反应,甚至过敏性休克。花椒过敏反应是由IgE介导的速发型食物过敏反应,部分患者可表现为速发相和迟发相双相反应。花椒变应原来自花椒籽,而不是花椒皮。对花椒高度敏感个体,花椒点刺试验有可能诱发全身过敏反应。目前检测到的花椒籽变应原致敏组分蛋白的相对分     

Primary and pollen-associated hazelnut allergy in school-aged children in Germany: A birth cohort study

BackgroundPrimary hazelnut allergy is a common cause of anaphylaxis in children, as compared to birch-pollen associated hazelnut allergy. Population-based data on hazelnut and concomitant birch-pollen allergy in children are lacking. We aimed to investigate the prevalence of primary and pollen-associated hazelnut allergy and sensitization profiles in school-aged children in Berlin, Germany.Methods1570 newborn children were recruited in Berlin in 2005–2009. The school-age follow-up (2014–2017) was based on a standardized web-based parental questionnaire and clinical evaluation by a physician including skin prick tests, allergen specific immunoglobulin E serum tests and placebo-controlled double-blind oral food challenges, if indicated.Results1004 children (63.9% response) participated in the school-age follow-up assessment (52.1% male). For 1.9% (n = 19, 95%-confidence interval 1.1%–2.9%) of children their parents reported hazelnut-allergic symptoms, for half of these to roasted hazelnut indicating primary hazelnut allergy. Symptoms of birch-pollen allergy were reported for 11.6% (n = 116 95%-CI 9.7%–13.7%) of the children. Both birch-pollen allergy and hazelnut allergy associated symptoms affected 0.6% (n = 6, 95%-CI 0.2%–1.3%) of children. Assessment of allergic sensitization was performed in 261 participants and showed that almost 20% of these children were sensitized to hazelnut, being the most frequent of all assessed food allergens, or birch-pollen, the majority to both.ConclusionsBased on parental reports hazelnut-allergic symptoms were far less common than sensitization to hazelnut. This needs to be considered by physicians to avoid unnecessary changes in diet due to sensitization profiles only, especially when there is a co-sensitization to hazelnut and birch-pollen.     

In vitro diagnostic evaluation of patients with inhalant allergies: summary of probability outcomes comparing results of CLA- and CAP-specific immunoglobulin E test systems.

For the diagnosis of allergy, presence of allergen-specific immunoglobulin E (IgE) usually is established either by allergen skin tests or by in vitro allergen-specific IgE measurements. However, in vitro assays of specific IgE often are modified as manufacturers improve allergens or change reagents to optimize test performance, affecting the diagnostic performance of in vitro allergen-specific IgE assays. This investigation compares the diagnostic outcomes of the Hitachi Chemical Diagnostics chemiluminescent assay (CLA) and Pharmacia, capsulated hydrophilic carrier polymer (CAP) in vitro allergen-specific IgE test methods in patients with inhalant allergy to a panel of selected allergens. Sera were obtained from 60 consecutive patients who had a clinical history suggesting inhalant allergy and were evaluated by allergen skin-prick test (SPT). Only patients with clinical findings of allergic asthma or rhinoconjunctivitis were included. Sera from patients with at least one positive SPT, which clinically correlated with the case history, were used for specific IgE measurements. Sensitivity and specificity were defined as conditional probabilities describing performances of the CAP system and the CLA system in reference to a standard composed of a combination of allergen-specific symptoms and a positive SPT. A test concordance of 79% was found between the CLA and CAP test results with a correlation coefficient of 0.8. Allergen-specific IgE assay sensitivity of the CLA and CAP systems was similar and allergen dependent, ranging from 67 to 100%. Assay specificity ranged from 39 to 86% for the CLA system and from 36 to 81% for the CAP system. When comparing the specific IgE results with allergen SPTs, 75% (+/- 3%) of CLApositive patients had a positive SPT, and 92% (+/- 4%) of CAPpositive patients had a positive SPT. Eighty-four percent (+/- 4%) of CLAnegative patients had a negative SPT, whereas 69% (+/- 5%) of CAPnegative patients had a negative SPT. The overall concordance between skin tests and in vitro tests was 76% for CLA and 67% for CAP. CLA and CAP score values showed good correlation and both tests may be useful when skin tests cannot be performed to identify subjects with IgE-mediated allergy. The CLA and CAP assays for allergen-specific IgE may be useful as part of an initial allergy evaluation because of the high negative predictive value of negative test results. For the majority of allergens the sensitivity was high. However, the specificity of both in vitro tests was low, indicating that positive in vitro test results should be evaluated carefully in conjunction with clinical symptoms and allergen-specific skin tests to determine the clinical relevance of the allergen sensitization.     

Gastrointestinal food hypersensitivity: Symptoms, diagnosis and provocation tests.

As many as 25% of the general population in Western countries believe that they suffer from adverse reactions to food. However, the actual prevalence of food allergy is much lower. Food-induced allergic reactions cause a variety of symptoms including cutaneous, gastrointestinal and respiratory tract. Food allergy might be caused by IgE-mediated, mixed (IgE and/or non-IgE) or non-IgE-mediated (cellular) mechanisms. The clinical diagnosis is based on a careful history, laboratory findings (total and specific IgE), skin prick test, elimination diet and food challenges. New intestinal provocation tests have also been applied to pick up the allergic response of the duodenal mucosa by endosonography and external ultrasound. The management of food allergy continues to be a strict avoidance of the offending food item.     

"In vivo" and "in vitro": tests in the diagnosis of trichophyton allergy

A group of 100 patients with Trichophyton allergy and a control of group of 100 without fungal allergy have been compared in order to evaluate the diagnostic value of skin prick and intradermal tests and assay of Trichophyton specific IgE. The evaluation of sensitivity, specificity efficacy, positive and negative predictive values suggests that skin tests in two steps, prick and intradermal and research of specific IgE must be used to a better diagnostic approach. In cases were allergy is not cleared by antifungal therapy specific immunotherapy is worthwhile to be tried with a great percentage of success.     

Diagnosis of Food Allergy: Epicutaneous Skin Tests, In Vitro Tests, and Oral Food Challenge

Food allergy is becoming an increasingly common diagnosis. Because of this increase in prevalence, it is imperative that physicians evaluating patients with possible adverse reactions to foods understand the currently available assays and how they should best be used to accurately diagnose the disease. Simple tests such as skin prick testing (SPT) and serum food-specific IgE testing are the most commonly used diagnostic tests to evaluate for IgE-mediated food reactions. However, these tests, which measure sensitization and not clinical allergy, are not without pitfalls, and their utility must be appreciated to avoid over- and underdiagnosis. Although the physician-supervised oral food challenge remains the gold standard for food allergy diagnosis, a careful medical history paired with SPT and serum food-specific IgE testing often can provide a reliable diagnosis. In this review, we examine the usefulness and pitfalls of SPT and serum food-specific IgE levels, as well as examine atopy patch testing and other emerging tests, such as component-resolved diagnostics and the basophil activation test. Finally, we describe the use of the double-blind, placebo-controlled oral food challenge as the current gold standard for food allergy diagnosis.     

L’allergie aux Rosacées chez l’enfant : à propos de vingt-deux cas

Rosaceae allergy is the fourth most frequent food allergy in Spanish children whereas it is rare in French children. The aim of the present study was to analyse the natural history of Rosaceae allergy in French children living in the Mediterranean area and to underline its specificities. We reviewed the case records of 22 children. The diagnosis of Rosaceae allergy was based on the clinical history and confirmed by skin prick tests with fresh foods and with commercial extracts and the Pharmacia CAP-RAST. Sensitivity to birch was also assessed by prick tests. The patients were divided into two groups: 12 children who were sensitised to Rosaceae and to birch pollen and eight who were sensitised to Roseacea only. The diagnostic value of prick tests with commercial extracts for Roseacea allergy was poor in both of these groups. The birch-negative group had become allergic to peaches first, and all of these children were sensitive to extracts of the cooked native fruits that were responsible for their clinical reactivity. Severe allergic reactions had occurred more frequently in this group. Prick tests with commercial extracts were positive only in this group. In contrast, the birch-positive group was more frequently allergic to apples, and the oral allergy syndrome was common among them. The median level of sensitisation to fresh fruits was also higher in this group. French children living in the Mediterranean appear to have a specific Rosaceae sensitisation profile: 60% of them have a Northern Europe profile (birch–apple allergy) and 40% of them have a Spanish–Italian profile (lipid-transfer protein allergy).     

Clinical value of morphine,pholcodine and poppy seed IgE assays in drug-abusers and allergic people

BackgroundThe diagnosis of anaphylactic reactions due to opiates during anaesthesia can be difficult, since in most cases various drugs may have been administered. Detection of specific IgE to poppy seed might be a marker for sensitisation to opiates in allergic people and heroin-abusers. This study assessed the clinical value of morphine, pholcodine and poppy seed skin-prick and IgE determination in people suffering hypersensitivity reactions during anaesthesia or analgesia and drug-abusers with allergic symptoms.MethodsWe selected heroin abusers and patients who suffered severe reactions during anaesthesia and analgesia from a database of 23,873 patients. The diagnostic yield (sensitivity, specificity and predictive value) of prick and IgE tests in determining opiate allergy was analysed.ResultsOverall, 149 patients and 200 controls, mean age 32.9 ± 14.7 years, were included. All patients with positive prick to opiates showed positive prick and IgE to poppy seeds, but not to morphine or pholcodine IgE. Among drug-abusers, 13/42 patients (31%) presented opium hypersensitivity confirmed by challenge tests. Among non-drug abusers, sensitisation to opiates was higher in people allergic to tobacco (25%), P<.001. Prick tests and IgE against poppy seed had a good sensitivity (95.6% and 82.6%, respectively) and specificity (98.5% and 100%, respectively) in the diagnosis of opiate allergy.ConclusionsOpiates may be significant allergens. Drug-abusers and people sensitised to tobacco are at risk. Both the prick and specific IgE tests efficiently detected sensitisation to opiates. The highest levels were related to more-severe clinical profiles.     

"Atopy patch tests" in the diagnosis of delayed food hypersensitivity

The prevalence of atopic diseases is increasing worldwide. Food allergies are the earliest manifestation of atopy. Atopic eczema affects about 18% of infants in the first 2 years of life and the main cause is allergy to multiple foods. A strong association has been shown between atopic eczema and IgE mediated allergy to milk, egg or peanut, but more than two-thirds of patients intolerant to food proteins have no evidence of IgE sensitization to the relevant food protein. Recently, patch testing with proteins has been found to be helpful in diagnosing food allergy in cases where skin prick tests and estimation of specific antibodies have failed. The methodology of atopy patch test (APT) is unstandardized, and contradictory results have been reported. In contrast to the more standardized APT methodology with aeroallergens, the sensitivities and specificities of food allergens can easily be estimated with food challenge tests. With multiallergic children adding of APTs to the skin prick tests and specific antibody estimation tests give more information for planning a wide enough elimination diet to get the skin and gastrointestinal tract symptomless in order to perform the challenge test which remains the only reliable test for food allergy. Standardization of the APT materials and reading procedure will add to the reliability of this new test method.     

Diagnostic tests for patients with suspected allergic disease. Utility and limitations

STUDY OBJECTIVE: To evaluate the clinical efficacy of diagnostic tests used for persons with suspected allergic disease. DESIGN: Information synthesis based on historical review of developments in the understanding of the pathophysiology of allergic diseases and on selected recent literature on efficacy of specific diagnostic tests. MAIN RESULTS: Skin testing is most effective when based on clues from the patient's history. The sensitivity and specificity of skin testing methods are compared: skin prick testing alone is often sufficient to identify or exclude immunoglobulin E (IgE)-mediated hypersensitivity, including food allergy. Except for penicillin and certain macromolecules, skin testing is not useful for evaluating drug allergy. Skin test titration may be useful for determining the starting dose for immunotherapy; otherwise it is rarely necessary. The patch skin test helps identify the cause of allergic contact dermatitis. Bronchial provocation testing is useful in special cases. Oral provocation testing may be used to identify allergy or other intolerance to suspected foods, food additives, and certain drugs. Provocation testing is time-consuming and requires special precautions. In-vitro methods for identifying allergen-specific IgE are especially useful when skin testing is unreliable, equivocal, or cannot be done. In-vitro tests should be used as adjuncts to the clinical interview and examination. CONCLUSIONS: Tests that are effective for identifying allergenic substances usually can be determined from a careful patient interview. Clinicians should be aware of nonspecific test results and allergy tests of unproven effectiveness.     

Prevalence of food allergy in 137 latex-allergic patients.

There have been reports of increased prevalence of certain food allergies in patients with Type I latex allergy (LA). A detailed food allergy history was obtained from 137 patients with LA. Latex allergy was defined by positive history of IgE mediated reactions to contact with latex and positive skin prick test to latex and/or positive in vitro test (AlaSTAT and/or Pharmacia CAP). Food allergy was diagnosed by a convincing history of possible IgE mediated symptoms occurring within 60 minutes of ingestion. We identified 49 potential allergic reactions to foods in 29 (21.1%) patients. Foods responsible for these reactions include banana 9 (18.3%), avocado 8 (16.3%), shellfish 6 (12.2%), fish 4 (8.1%), kiwi 6 (12.2%), tomato 3 (6.1%), watermelon, peach, carrot 2 (4.1%) each, and apple, chestnut, cherry, coconut, apricot, strawberry, loquat, one (2.0%) each. Reactions to foods included local mouth irritation, angioedema, urticaria, asthma, nausea, vomiting, diarrhea, rhinitis, or anaphylaxis. Our study confirms the earlier reports of increased prevalence of food allergies in patients with LA. We also report increased prevalence of shellfish and fish allergy not previously reported. The nature of cross reacting epitopes or independent sensitization between latex and these foods is not clear.     

Eosinophilic esophagitis

BackgroundEsophagitis is an increasingly diagnosed disease. Patients with gastroesophagic reflux, dysphagia, vomiting or abdominal pain, with a torpid response to the treatment, could be suffering from it.Material and methodsA 37 year-old male patient with background of gastroesophagic reflux and dysphagia for solids since 2002, self-limited diarrhea episodes and intolerance to alcoholic drinks due to epigastric pain. Skin prick tests, specific IgE, histamine release test and basophil activation test were carried out.ResultsSkin prick test to the usual allergens with negative result; prick-prick tests to egg white and yolk, milk and apple with positive result to egg white; total serum IgE within normal levels, specific IgE to egg white with positive result; histamine release test (HRT) and basophil activation test (BAT) with positive result to egg white and yolk.ConclusionThe patient was diagnosed eosinophilic esophagitis. The commercial food extracts have a great variability in their allergenic composition, which could result in false negative results in the prick test. Prick-prick with the natural food is a more sensitive technique than prick in the diagnosis of food allergy. There are other useful in vitro techniques, apart from specific IgE, in the diagnosis of food allergy. In our case, an exclusion diet of the involved food was more effective than other treatments for remission of the symptoms.