Cause Of Severe Allergic Reactions Research Articles

Poppy Seed Allergy: Molecular Diagnosis and Cross-Reactivity With Tree Nuts

BackgroundPoppy seed (PS) can be a cause of severe allergic reactions, especially in individuals with concurrent allergy to tree nuts and other seeds, but diagnostic criteria and sensitization patterns are lacking. ObjectiveTo assess the role of PS extract and individual allergens in diagnosing PS allergy and their cross-reactivities with tree nuts and buckwheat. MethodsOur retrospective study included 36 PS-sensitized patients; 10 with positive and 26 with a negative oral food challenge (OFC). We identified individual PS allergens and compared the diagnostic performance of sIgE to PS extract to its allergens. Cross-reactivities between PS and related allergens from other seeds was assessed by competitive ELISA. ResultsWe identified four novel PS allergens: Pap s 1 (vicilin), Pap s 1 (27-424) (α-hairpinin), Pap s 2 (legumin), and Pap s 3 (small hydrophilic seed protein). Positive OFC correlated with higher PS-sIgE levels and elevated sIgE levels for the PS allergens, except for Pap s 3. PS and α-hairpinin-sIgE effectively differentiated allergic from tolerant patients, with AUC values of 0.95 and 0.94. PS-sIgE >10.00 kUA/L exhibited 90% sensitivity and 73% specificity, while α-hairpinin -sIgE >2.60 kUA/L showed 100% sensitivity and 77% specificity. PS vicilin and legumin highly cross-reacted with hazelnut and buckwheat homologues, while α-hairpinin-sIgE cross-reacted with the related almond allergen. ConclusionsThis is the most extensive study on poppy seed allergy to date. Poppy seed and α-hairpinin-sIgE are highly sensitive indicators of clinical reactivity to poppy seeds, while vicilin and legumin-sIgE contribute to concurrent sensitization to hazelnut and buckwheat.

Reproducibility of food challenge to cow’s milk: Systematic review with individual participant data meta-analysis

Cow's milk (CM) is an increasingly common cause of severe allergic reactions, but there is uncertainty with respect to severity of reactions at low-level CM exposure, as well as the reproducibility of reaction thresholds. We undertook an individual participant data (IPD) meta-analysis of studies reporting double-blind, placebo-controlled food challenges in CM to determine the rate of anaphylaxis to low-level exposures and the reproducibility of reaction thresholds. We performed a systematic review and IPD meta-analysis of studies reporting relevant data. Authors were contacted to provide additional data and/or clarification as needed. Risk of bias was assessed using the National Institute for Clinical Excellence methodologic checklists. Thirty-four studies were included, representing data from over 1000 participants. The cumulative ED₀₁ and ED₀₅ (cumulative doses causing objective symptoms in 1% and 5% of the at-risk allergic population) were 0.3 (95% confidence interval [CI], 0.2-0.5) and 2.9 (95% CI, 1.6-5.4) mg, respectively. At meta-analysis, 4.8% (95% CI, 2.0-10.9) and 4.8% (95% CI, 0.7-27.1) of individuals reacting to ≤5 mg and ≤0.5 mg of CM protein had anaphylaxis (minimal heterogeneity, I²= 0%). Then 110 individuals underwent repeat double-blind, placebo-controlled food challenges; the intraindividual variation in reaction threshold was limited to a ½-log change in 80% (95% CI, 65-89) of participants. Two individuals initially tolerated 5 mg CM protein but then reacted to this dose at a subsequent challenge, although neither had anaphylaxis. About 5% of CM-allergic individuals reacting to ED₀₁ or ED₀₅ exposure might have anaphylaxis to that dose. This equates to 5 and 24 anaphylaxis events per 10,000 patients exposed to an ED₀₁ or ED₀₅ dose, respectively, in the broader CM-allergic population. Most of these anaphylactic reactions would be mild and respond to a single dose of epinephrine.

Food-Induced Anaphylaxis: Role of Hidden Allergens and Cofactors.

Food anaphylaxis is on the increase, with those who have an allergy to peanuts, tree nuts, milk, and seafood at the highest risk of developing such a reaction. However, the diet in many societies is increasingly varied, much of the food consumed is prepared outside the home, and meals are often composed of many different ingredients. Anaphylaxis may occur to a composite food, and it may be unclear whether the reaction is due to contamination or to a culprit allergen present in an added ingredient. Composite foods can contain many allergic proteins present in small amounts, which do not always have to be labeled, unless they feature in European or US labeling regulations. These “hidden” allergens include mustard, celery, spices, lupine, pea, natural food colourings, and preservatives, but can occasionally include allergenic material from contaminants such as cereal mites. Hidden allergens can provoke severe reactions to seemingly unconnected foods which might then lead to a diagnosis of idiopathic anaphylaxis. The same problem can arise with two well-known types of food allergy; wheat-dependant exercise induced anaphylaxis and allergy to non-specific Lipid Transfer Protein allergens, both of which might only manifest when linked to a cofactor such as exercise. Many of these risk factors for food anaphylaxis have a common link; the public's engagement with popular concepts of health and fitness. This includes the development of a food and exercise culture involving the promotion and marketing of foods for their health-giving properties i.e., meat substitutes, wheat substitutes, supplements and alternative, or “natural” remedies for common ailments. Some of these foods have been reported as the cause of severe allergic reactions, but because they are often viewed as benign unlikely causes of severe allergic reactions, could be considered to be hidden allergens. The best resource to elicit the likelihood of a hidden allergen provoking an allergic reaction is to take a detailed history of the allergic reaction, presence of co-factors, foods suspected, type of food and where it was consumed. A good knowledge of commonly used ingredients, and list of potential hidden allergen suspects are essential tools for the food allergy detective.

Oxytocin: an unexpected risk for cardiologic and broncho-obstructive effects, and allergic reactions in susceptible delivering women.

Oxytocin (Sintocynon) is considered an uncommon cause of severe allergic reactions during delivery. We have recently shown that allergic sensitization to latex might constitute an important predisposing risk factor for anaphylaxis after the first infusion of oxytocin during delivery.Some oxytocin cardiovascular activities such as lowering blood pressure, negative cardiac inotropy and cronotropy, parasympathetic neuromodulation, vasodilatation etc. can induce significant side effects mimicking cardiac anaphylaxis, and constitute an additional differential diagnostic problem in delivering women with suspected or real allergic background. Finally, some ex vivo models have shown that oxytocin, under pro-inflammatory cytokines stimulation, such as those occurring in asthma, may induce contraction of smooth muscle and airway narrowing.This background suggests that allergic sensitization to latex allergens constitutes a significant but underestimated risk factor for triggering severe systemic reactions after the infusion of oxytocin and, consequently, there is a need of particular attention in managing delivering women suffering from latex allergy and bronchial asthma. An accurate anamnestic, clinical and diagnostic evaluation, latex-free anesthesiological setting, use of oxytocin-alternative agents and, if necessary, a drug premedication are likely to reduce the risk of anaphylactic/broncho-obstructive reactions in these women.

Oxytocin: an unexpected risk for cardiologic and broncho-obstructive effects, and allergic reactions in susceptible delivering women

Oxytocin (Sintocynon) is considered an uncommon cause of severe allergic reactions during delivery. We have recently shown that allergic sensitization to latex might constitute an important predisposing risk factor for anaphylaxis after the first infusion of oxytocin during delivery. Some oxytocin cardiovascular activities such as lowering blood pressure, negative cardiac inotropy and cronotropy, parasympathetic neuromodulation, vasodilatation etc. can induce significant side effects mimicking cardiac anaphylaxis, and constitute an additional differential diagnostic problem in delivering women with suspected or real allergic background. Finally, some ex vivo models have shown that oxytocin, under pro-inflammatory cytokines stimulation, such as those occurring in asthma, may induce contraction of smooth muscle and airway narrowing. This background suggests that allergic sensitization to latex allergens constitutes a significant but underestimated risk factor for triggering severe systemic reactions after the infusion of oxytocin and, consequently, there is a need of particular attention in managing delivering women suffering from latex allergy and bronchial asthma. An accurate anamnestic, clinical and diagnostic evaluation, latex-free anesthesiological setting, use of oxytocin-alternative agents and, if necessary, a drug premedication are likely to reduce the risk of anaphylactic/broncho-obstructive reactions in these women.

Modeling of allergen proteins found in sea food products

Shellfish are a source of food allergens, and their consumption is the cause of severe allergic reactions in humans. Tropomyosins, a family of muscle proteins, have been identified as the major allergens in shellfish and mollusks species. Nevertheless, few experimentally determined three-dimensional structures are available in the Protein Data Base (PDB). In this study, 3D models of several homologous of tropomyosins present in marine shellfish and mollusk species (Chaf 1, Met e1, Hom a1, Per v1, and Pen a1) were constructed, validated, and their immunoglobulin E binding epitopes were identified using bioinformatics tools. All protein models for these allergens consisted of long alpha-helices. Chaf 1, Met e1, and Hom a1 had six conserved regions with sequence similarities to known epitopes, whereas Per v1 and Pen a1 contained only one. Lipophilic potentials of identified epitopes revealed a high propensity of hydrophobic amino acids in the immunoglobulin E binding site. This information could be useful to design tropomyosin-specific immunotherapy for sea food allergies.

Allergy to fruit seeds presenting with anaphylaxis

Allergic reactions to fruits, particularly citrus, are relatively common, often presenting with symptoms of oral allergy syndrome (also known as pollen-food syndrome), with systemic allergic reactions occurring less frequently. Fruit allergy testing, including serum specific immunoglobulin E (IgE) and skin prick testing will identify the allergen in most cases, however these tests commonly use extract from the fruit and may fail to identify reactions to the seed, which may be more severe. We report three children with anaphylactic reactions to fruit seeds, who were able to tolerate the fruit pulp. Two children experienced anaphylaxis to orange seed, and both had evidence of sensitisation to multiple citrus seeds, peanut and tree nuts. The third child developed anaphylaxis to a commercially-produced baby food containing apple puree, and was found to be sensitised to a range of fruit and citrus seeds, as well as to sesame and nuts. These cases highlight the need to consider fruit seeds as a potential cause of severe allergic reactions to fruit.

Food allergy in Asia

Food allergy is increasing in prevalence in Western populations, but little is known about it in Asia. The perception is that the prevalence in this region is low, but is likely to increase with the global increase in allergy. Asia is unique because of the many different cultures and eating habits, with the resulting occurrence of unique food allergens. This review describes the epidemiology and clinical features of food allergy, and introduces some of the unusual food allergens in Asia. Recent studies describing the pattern of anaphylaxis and the role of food triggers show that food is an important cause of severe allergic reactions in Asia. Progress has been made on the characterization of unique food allergens from the region. Peanut and tree nuts are rarely the cause of allergic reactions in Asia. The lack of availability of epinephrine auto-injectors in many countries is an important issue that needs to be addressed. The pattern of food allergy in Asia is unique. Unfortunately, data from many parts of Asia are still lacking. Large, well-designed epidemiological studies are needed so that the scale of the problem can be understood, public awareness can be increased and important food allergens in the region can be identified.

How dangerous is food allergy?

Food allergy is the inappropriate and harmful response of the immune system to specific food proteins that are normally harmless. In susceptible individuals, adverse reactions can range from mild skin reactions to severe and life-threatening reactions. Food allergy is the most common cause of severe allergic reactions in children. The connection between danger and allergy is deeply ingrained in the public and medical consciousness. Communication of the risks, or lack of risk, of life-threatening reactions, although important, is not the whole story in managing rapid hypersensitivity. Paramount is the need for a ‘care package’ including advice and backup as well as appropriate treatments.

Ant allergy in Asia and Australia.

Anaphylaxis due to ant sting is increasingly being recognized as a significant problem. Severe allergic reactions to ants are well described in the south-eastern United States, but have only been recognized in recent years as being important in other parts of the world. There are many different ant species and their distribution around the world varies. The purpose of this review is to familiarize the reader with the epidemiology and clinical characteristics of ant allergy in Asia and Australia. In Korea, allergy to Pachycondyla chinensis (subfamily Ponerinae) has been well described. In an ant-endemic area, sensitization was 23%, with about 1% having anaphylactic reactions. There were at least eight IgE-binding proteins in P. chinensis venom, with 1 major allergen binding 85% of patient sera. P. chinensis venom was also found to be possibly crossreactive with bee venom, but not with imported-fire-ant venom. In Australia, anaphylactic reactions to ant stings are usually caused by the 'jack jumper' ant (Myrmecia pilosula) or the bull ant (Myrmecia pyriformis). A recent study showed promising results for immunotherapy with M. pilosula venom. There have been reports of stings by other ant species in Asia and Australia, but these reports are few and sporadic. The study of ant allergy in Asia is in its infancy. Clinicians in Asia need to be aware of ant stings as a cause of severe allergic reactions. Certain species that cause allergic reactions are unique to Asia and Australia and deserve further research. The allergens in the venom of the different ant species need to be identified. We should aim for improved understanding of the epidemiology of ant-sting anaphylaxis, formulation of better diagnostic tests and possibly the introduction of immunotherapeutic strategies.

Two cases of ortho-phthalaldehyde induced allergic reactions in patients undergoing surveillance cystoscopy

Rationale Sterilizing agents, including gluteraldehyde, have been implicated as causes of immunologic respiratory reactions. Ortho-phthalaldehyde (OPA), a gluteraldehyde-free agent, is recognized as an alternative disinfectant and has not been associated with allergic hypersensitivity. We report two cases in which OPA has been implicated as the cause of anaphylaxis and angioedema. Methods Case 1: WP is a 70-year-old man diagnosed with bladder cancer three years prior to presentation and has been followed by routine cystoscopic evaluations every three months. After his ninth cystoscopy, WP noted immediate pruritis and angioedema of his genitals followed by urticaria, dyspnea, hypotension, and syncope which responded to IV fluids and diphenhydramine. Our evaluation included RAST for latex, skin testing to local anesthetics, topical lidocaine gel, and the disinfectant–OPA. Case 2: AK is a 68-year-old man diagnosed with bladder cancer 18 months prior to evaluation who is followed by surveillance cystoscopies every three months. His most recent one resulted in immediate angioedema of his genitals and lower abdomen that progressively worsened over the next hour. Our evaluation was similar to the one described in case 1. Results In both cases, the latex RAST and skin tests for local anesthetics and topical lidocaine gel were negative. The pricks for OPA in serum albumin were positive at a 1:10,000 dilution in each patient. Conclusions These are the first reported cases of urticaria, angioedema and anaphylaxis associated with OPA. This gluteraldehyde-free agent should be considered a possible cause of severe allergic reactions in those exposed to it during endoscopic procedures.