The predictive value of skin prick testing for challenge-proven food allergy: a systematic review

Canadian Society of Allergy and Clinical Immunology position statement: panel testing for food allergies

This position statement addresses the critical concerns and recommended practices surrounding the use of panel food testing for diagnosing food allergies. Food allergies are a significant public health concern, and the misdiagnosis of food allergies remains a prevalent concern, made worse by the ongoing use of panel food testing. The practice of screening patients for multiple food allergens, regardless of clinical relevance, is commonly referred to as "panel food testing." Fundamentally, a panel food test is not simply a single test; a panel food test is a series of several distinct tests for multiple foods, each with its own variable predictive value. These tests have not been adequately validated as screening tests and carry a considerable false positive rate. The resulting false diagnoses lead to unnecessary dietary restrictions, increased healthcare costs, and significant psychosocial distress for patients and their families.

Cow's milk allergy skin tests: fresh milk, commercial extracts, or both?

BACKGROUND

The diagnosis of food allergy is based on a history of immediate allergic reaction following food ingestion, and skin prick test (SPT) demonstrating sensitization with commercial extracts (CE) or fresh food (FF). For most food allergens, the SPT with FF is considered more accurate and predictive. Regarding cow's milk, the results are inconclusive. This retrospective study aimed to evaluate the accuracy of SPT with fresh milk compared to CE (cow's milk and casein) for evaluation of cow's milk allergy (CMA).

METHODS

This study summarized the medical records of children, diagnosed with CMA. The data include demographics, skin tests and oral food challenge results, as well as atopic comorbidities.

RESULTS

Records of 698 patients with the diagnosis of CMA were reviewed, 388 fulfilled the inclusion criteria. Overall, 134 patients (34.54%) had an additional atopic disease. The SPT wheal size with fresh milk was significantly larger than with CE (cow's milk and casein) at first evaluation or before oral food challenge (OFC). Combination of SPT results (CE and FF) gave the maximal odds ratio for reaction during OFC and SPT with fresh milk alone gave the minimal OR (34.18 and 4.74, respectively).

CONCLUSIONS

SPT with CE for CMA evaluation is more reliable than SPT performed with fresh milk. In patients suspected of having IgE-mediated CMA, before deciding on performing OFC, it is advised to perform SPT with at least two different extracts, and always include casein. Fresh milk can serve as a backup if commercial extracts are not available. In cases that the SPT with fresh milk is 3 mm or less, there is 93.3% chance that the OFC will pass without reaction. Trial registration This study protocol was reviewed and approved by the Ethics Committee of Meir Medical Center, IRB Number 0083-18 MMC.

Blocking the inhibitory receptor programmed cell death 1 prevents allergic immune response and anaphylaxis in mice

BACKGROUND

Food allergy and acute anaphylaxis can be life-threatening. While T follicular helper (Tfh) cells play a pivotal role in the allergic immune responses, the immunologic mechanisms that regulate the production of antibodies (Abs) that mediate anaphylaxis are not fully understood.

OBJECTIVE

The aim of this study was to investigate the role of the inhibitory receptor programmed cell death protein 1 (PD-1), which is highly expressed on Tfh cells, in allergic immune responses using an animal model of peanut allergy and anaphylaxis.

METHODS

Naive wild-type mice were exposed to peanut flour intranasally and then challenged with peanut extract to induce systemic anaphylaxis. The roles of PD-1 were examined by blocking Abs and using gene-deficient animals. A hapten model and passive cutaneous anaphylaxis were used to characterize allergen-specific Abs.

RESULTS

Treatment with anti-PD-1 enhanced development of Tfh cells and germinal center B cells in mice exposed to peanut flour. Nonetheless, anti-PD-1 or its ligand fully protected mice from developing anaphylaxis. Anti-PD-1 treatment or genetic deficiency of PD-1 in CD4⁺ T cells inhibited production of peanut-specific IgE and increased the levels of IgG. The passive cutaneous anaphylaxis showed that peanut-specific Abs generated in anti-PD-1-treated animals prevented, rather than provoked, anaphylaxis when transferred to naive animals. Anti-PD-1 promoted production of Abs with low affinity for an antigen in the hapten model.

CONCLUSION

Blockade of the pathway between PD-1 and its ligand is protective against allergic immune responses. The direct interaction between Tfh cells and B cells may play a pivotal role in controlling Ab quality and clinical manifestation of allergic diseases.

Diagnostic therapeutic care pathway for pediatric food allergies and intolerances in Italy: a joint position paper by the Italian Society for Pediatric Gastroenterology Hepatology and Nutrition (SIGENP) and the Italian Society for Pediatric Allergy and Immunology (SIAIP)

Epidemiologic data suggest an increased prevalence of pediatric food allergies and intolerances (FAIs) during the last decades. This changing scenario has led to an increase in the overall healthcare costs, due to a growing demand for diagnostic and treatment services. There is the need to establish Evidence-based practices for diagnostic and therapeutic intervention that could  be adopted in the context of public health policies for FAIs are needed.

This joint position paper has been prepared by a group of experts in pediatric gastroenterology, allergy and nutrition from the Italian Society for Pediatric Gastroenterology Hepatology and Nutrition (SIGENP) and the Italian Society for Pediatric Allergy and Immunology (SIAIP). The paper is focused on the Diagnostic Therapeutic Care Pathway (DTCP) for pediatric FAIs in Italy.

Real world use of peanut component testing among children in the Chicago metropolitan area

Background: Peanut component tests (PCT) have become important in the evaluation of peanut allergy. There remains a paucity of research across the United States in investigating the utility of PCT in clinical practice in conjunction with current standards of care. Objective: The primary aims were to evaluate the performance and sensitization patterns of PCT in clinical practice when first available at our institution. Methods: We performed a retrospective chart review of 184 children with PCT and oral food challenge (OFC) results between 2012 and 2017. Simple logistic regression models assessed the associations between PCT and OFC outcomes. Receiver operator characteristic curves were constructed, and a predicted probability curve was derived for Ara h2. Results: The median (interquartile range [IQR]) age at OFC was 4 years (2-7 years), and 111 patients (60%) were boys. Ara h 2 was the most commonly sensitized PCT. Sixty-one patients (33%) reacted at OFC. Ara h 2 specific immunoglobulin E (sIgE) ≥ 0.35 kU_A/L was associated with increased odds of reacting at OFC (odds ratio 5.91 95% confidence interval, 2.93-11.89; p < 0.001); however, 19 patients (37%) positive for Ara h 2 did not react. Ara h 2 sIgE of 0.49 kU_A/L and 4.58 kU_A/L were associated with 50% and 90% probability, respectively, of reacting at OFC. Among those sensitized only to Ara h 8 or 9 (n = 21), 86% had no reaction. There was no statistically significant association with polysensitization to Ara h 1, 2, and 3, and peanut OFC outcome. Conclusion: Although the Ara h 2 sIgE value was associated with clinical reactivity, a significant proportion of the patients sensitized to Ara h 2 tolerated peanut. OFC remains an important tool in the evaluation of peanut allergy.

Diagnosis and Management of Food Allergy

Food allergy is an immune-mediated disease and must be differentiated from other adverse effects related to food that are non-immune mediated. Symptoms of immunoglobulin (Ig) E-mediated allergy can range from mild to severe, and life-threatening anaphylaxis may occur. Current recommended strategies for diagnosis include the use of skin prick tests, allergen-specific serum IgE, and/or oral food challenges. Management entails allergen avoidance and appropriate treatment of allergic reactions should accidental ingestions occur. Treatment approaches under investigation include immunotherapy as well as biologics and novel vaccines. Attention has also recently focused on implementing strategies for prevention of food allergy.

Nutritional Aspects of Pediatric Gastrointestinal Diseases

In the last decade, the role of nutritional management in pediatric gastrointestinal diseases has gained increasing popularity. Disease-specific diets have been introduced as conventional treatments by international guidelines. Patients tend to more willingly accept food-based therapies than drugs because of their relatively “harmless” nature. Apart from a diet’s therapeutic role, nutritional support is crucial in maintaining growth and improving clinical outcomes in pediatric patients. Despite the absence of classical “side effects”, however, it should be emphasized that any dietary modification might have negative consequences on children’s growth and development. Hence, expert supervision is always advised, in order to support adequate nutritional requirements. Unfortunately, the media provide an inaccurate perception of the role of diet for gastrointestinal diseases, leading to misconceptions by patients or their caregivers that tends to overestimate the beneficial role of diets and underestimate the potential adverse effects. Moreover, not only patients, but also healthcare professionals, have a number of misconceptions about the nutritional benefits of diet modification on gastrointestinal diseases. The aim of this review is to highlight the role of diet in pediatric gastrointestinal diseases, to detect misconceptions and to give a practical guide for physicians on the basis of current scientific evidence.

A Clinical Perspective on the Dietary Therapies for Pediatric Eosinophilic Esophagitis: The Gap Between Research and Daily Practice

Pediatric eosinophilic esophagitis (ped-EoE) is an immune-mediated pathology affecting 34 per 100.000 children. It is characterized by an esophageal inflammation caused by an immune response towards food antigens that come into contact with the esophageal lining. Depending on the age of the child, symptoms can vary from abdominal pain, vomiting and failure to thrive to dysphagia and food impaction. The diagnosis of this chronic disease is based on the symptoms of esophageal dysfunction combined with an infiltration of more than 15 eosinophils per high-power field and the exclusion of secondary causes. The treatment modalities include the 3Ds: Drugs, allergen avoidance by Diet and/or esophageal Dilation. In this review we focused on the efficacy of dietary approaches in ped-EoE, which currently include the elemental diet (amino acid-based diet), the empiric elimination diet and the allergy test-directed elimination diet. Although several reviews have summarized these dietary approaches, a lack of consistency between and within the elimination diets hampers its clinical use and differences in subsequent reintroduction phases present a barrier for dietary advice in daily clinical practice. We therefore conducted an analysis driven from a clinician's perspective on these dietary therapies in the management of ped-EoE, whereby we examined whether these variations within dietary approaches, yet considered to be similar, could result in significant differences in dietary counseling.

Update on food allergy

Food allergy is a major public health issue with growing prevalence in the urbanized world and significant impact on the lives of allergic patients and their families. Research into the risk factors that have contributed to this increase and their underlying immune mechanisms could lead us to definitive ways for treatment and prevention of food allergy. For the time being, introduction of peanut and other allergenic foods in the diet at the time of weaning seems to be an effective way to prevent the development of food allergy. Improved diagnosis and appropriate management and support of food allergic patients are central to patient care with food immunotherapy and biologics making the transition to clinical practice. With the new available treatments, it is becoming increasingly important to include patients' and family preferences to provide a management plan tailored to their needs.

Proven Food-Induced Acute Urticaria and Predictive Factors for Definitive Diagnosis in Childhood

BACKGROUND

Urticaria can be the only sign of a food allergy or can be seen together with other signs and symptoms of a food allergy.

OBJECTIVE

To determine the demographic, etiologic, and clinical features of food-induced acute urticaria in childhood.

METHODS

Patients suspected of food-induced acute urticaria were included in this prospective cross-sectional multicenter study.

RESULTS

Two hundred twenty-nine urticaria cases were included in this study. Seventeen patients who did not meet the inclusion criteria of the study were excluded. Of the 212 included cases, 179 (84.4%) were diagnosed with definitive food-induced acute urticaria. The most common foods causing acute urticaria were cow's milk, hen's eggs, and nuts in 56.4, 35.2, and 19% of cases, respectively. The positive predictive value of a history of milk-induced acute urticaria together with a milk-specific IgE >5 kU/L for cow's milk-induced acute urticaria was 92% (95% CI: 81-96%). A history of cow's milk-induced and/or hen's egg-induced acute urticaria was consistent with a definitive diagnosis of food-induced urticaria (Chen's kappa: 0.664 and 0.627 for milk and eggs, respectively). Urticaria activity scores were higher in patients with food-induced acute urticaria (p = 0.002).

CONCLUSION

Cow's milk, hen's eggs, and nuts were the most common allergens in the etiology of childhood food-induced acute urticaria. Although the urticaria activity score provides guidance for diagnosis, an oral food challenge is often essential for the definitive diagnosis of a patient with a history of food-induced acute urticaria.

Increased Frequency of CTLA-4 and PD-1 Expressing Regulatory T Cells and Basophils With an Activating Profile in Infants With Moderate-to-Severe Atopic Dermatitis Hypersensitized to Food Allergens

Background: Infants with severe atopic dermatitis (AD) may be sensitized to foods that have not been introduced into their diet, posing a risk for developing an immediate hypersensitivity reaction on the first exposure to the food to which they are sensitized. The aim of this work was to perform an analysis of the sensitization profile in infants with moderate-to-severe AD and to identify cellular and molecular markers for food allergy (FA). Methods: Blood samples from healthy donors and children with moderate-to-severe AD were studied. Specific IgE to several allergens were determined using ImmunoCAP FEIA system and ISAC technology. Furthermore, using flow cytometry-based studies, basophils and regulatory T (Treg) cells were phenotypically characterized. Results: 90% of children with AD were sensitized to food antigens before introducing them into the diet, and 100% developed FA. Phenotypic analysis showed a significantly higher percentage of CTLA-4 and PD-1 expressing Treg cells in AD patients than in healthy controls. Basophils from patients exhibited a marked reduction in the expression of CD300a, higher expression of FcεRI and CXCR4, and to some extent higher expression of CD63 and CD300c. Conclusions: Infants with moderate-to-severe AD are at high risk of being sensitized to food allergens. Therefore, to avoid allergic reactions, broad-spectrum sensitization studies are necessary before introducing complementary diet. Increased expression of CTLA-4 and PD-1 suggests greater suppressive potential of Treg cells in infants with AD than healthy controls. Furthermore, our results suggest a role for CD300 molecules on circulating basophils as possible biomarkers for FA susceptibility.

Sialylation of immunoglobulin E is a determinant of allergic pathogenicity

Approximately one-third of the world's population suffers from allergies¹. Exposure to allergens crosslinks immunoglobulin E (IgE) antibodies that are bound to mast cells and basophils, triggering the release of inflammatory mediators, including histamine². Although IgE is absolutely required for allergies, it is not understood why total and allergen-specific IgE concentrations do not reproducibly correlate with allergic disease^3-5. It is well-established that glycosylation of IgG dictates its effector function and has disease-specific patterns. However, whether IgE glycans differ in disease states or affect biological activity is completely unknown⁶. Here we perform an unbiased examination of glycosylation patterns of total IgE from individuals with a peanut allergy and from non-atopic individuals without allergies. Our analysis reveals an increase in sialic acid content on total IgE from individuals with a peanut allergy compared with non-atopic individuals. Removal of sialic acid from IgE attenuates effector-cell degranulation and anaphylaxis in several functional models of allergic disease. Therapeutic interventions-including removing sialic acid from cell-bound IgE with a neuraminidase enzyme targeted towards the IgE receptor FcεRI, and administering asialylated IgE-markedly reduce anaphylaxis. Together, these results establish IgE glycosylation, and specifically sialylation, as an important regulator of allergic disease.

Clinical factors associated with peanut allergy in a high-risk infant cohort

BACKGROUND

Prognostication of peanut allergy (PNA) is relevant for early interventions. We aimed to determine baseline parameters associated with the development of PNA in 3- to 15-month-olds with likely egg and/or milk allergy, and/or moderate to severe atopic dermatitis (AD) and a positive egg/milk skin prick test (SPT), but no known PNA.

METHODS

The primary endpoint was PNA [confirmed/convincing diagnosis or last classified as serologic PNA (<2 years, ≥5 kUA/L, otherwise ≥14 kUA/L, peanut IgE)] among 511 participants (median follow-up, 7.3 years). Associations were explored with univariate logistic regression; factors with P < 0.15 were analyzed by stepwise multiple logistic regression, using data stratified by PNA status and randomly assigned to development and validation datasets.

RESULTS

205/511 (40.1%) had PNA. Univariate factors associated with PNA (P < 0.01) included increased AD severity, larger egg and peanut SPT, greater egg, milk, peanut, Ara h1-h3 IgE, higher peanut IgG and IgG4, and increased pregnancy peanut consumption. P-values were between 0.01 and 0.05 for younger age, non-white race, lack of breastfeeding, and increased lactation peanut consumption. Using a development dataset, the multivariate model identified younger age at enrollment, greater peanut and Ara h2 IgE, and lack of breastfeeding as prognosticators. The final model predicted 79% in the development and 75% in the validation dataset (AUC = 0.83 for both). Models using stricter or less strict PNA criteria both found Ara h2 as predictive.

CONCLUSIONS

Key factors associated with PNA in this high-risk population included lack of breastfeeding, age, and greater Ara h2 and peanut-specific IgE, which can be used to prognosticate outcomes.

Diagnosis and Management of Food Allergy

Food allergy is an immune-mediated disease and must be differentiated from other adverse effects related to food that are non-immune mediated. Symptoms of immunoglobulin (Ig) E-mediated allergy can range from mild to severe, and life-threatening anaphylaxis may occur. Current recommended strategies for diagnosis include the use of skin prick tests, allergen-specific serum IgE, and/or oral food challenges. Management entails allergen avoidance and appropriate treatment of allergic reactions should accidental ingestions occur. Treatment approaches under investigation include immunotherapy as well as biologics and novel vaccines. Attention has also recently focused on implementing strategies for prevention of food allergy.

Component-resolved diagnostics in the clinical and laboratory investigation of allergy

The diagnosis and management of allergy is complex; the clinical symptoms associated with allergic reactions span a broad spectrum of severity, from mild hay fever-type symptoms through to life-threatening anaphylaxis. Obtaining an allergy-focused clinical history is therefore vital for identifying possible allergic triggers and directing testing. However, this focus could be changing as scientific and technological advances have paved the way for developments within in vitro testing for allergy. With knowledge of allergens at the molecular level expanding, there are now the facilities to characterize the sensitization profiles of allergy sufferers and determine the specific molecules (or components) against which the allergen-inducing immunoglobulin type E proteins have been produced. This technology is termed component-resolved diagnostics. We know that accurate identification of immunoglobulin type E specificity, the source of the causative allergen, and knowledge of potential allergic cross-reactivities are required for optimal clinical management of allergy patients. These factors can make allergy a diagnostic challenge outside of a specialist centre, and contribute to the difficulties associated with requesting and interpreting allergy tests. The incorporation of component-resolved diagnostics into current practice has provided a platform for patient-tailored risk stratification and improved the application of allergen-specific immunotherapy, revolutionizing specialist management of these patients. This review discusses the roles of each type of testing in allergy management and predictions for future pathways.

Analysis of a Large Standardized Food Challenge Data Set to Determine Predictors of Positive Outcome Across Multiple Allergens

Background: Double-blind placebo-controlled food challenges (DBPCFCs) remain the gold standard for the diagnosis of food allergy; however, challenges require significant time and resources and place the patient at an increased risk for severe allergic adverse events. There have been continued efforts to identify alternative diagnostic methods to replace or minimize the need for oral food challenges (OFCs) in the diagnosis of food allergy.

Methods: Data was extracted for all IRB-approved, Stanford-initiated clinical protocols involving standardized screening OFCs to a cumulative dose of 500 mg protein to any of 11 food allergens in participants with elevated skin prick test (SPT) and/or specific IgE (sIgE) values to the challenged food across 7 sites. Baseline population characteristics, biomarkers, and challenge outcomes were analyzed to develop diagnostic criteria predictive of positive OFCs across multiple allergens in our multi-allergic cohorts.

Results: A total of 1247 OFCs completed by 427 participants were analyzed in this cohort. Eighty-five percent of all OFCs had positive challenges. A history of atopic dermatitis and multiple food allergies were significantly associated with a higher risk of positive OFCs. The majority of food-specific SPT, sIgE, and sIgE/total IgE (tIgE) thresholds calculated from cumulative tolerated dose (CTD)-dependent receiver operator curves (ROC) had high discrimination of OFC outcome (area under the curves > 0.75). Participants with values above the thresholds were more likely to have positive challenges.

Conclusions: This is the first study, to our knowledge, to not only adjust for tolerated allergen dose in predicting OFC outcome, but to also use this method to establish biomarker thresholds. The presented findings suggest that readily obtainable biomarker values and patient demographics may be of use in the prediction of OFC outcome and food allergy. In the subset of patients with SPT or sIgE values above the thresholds, values appear highly predictive of a positive OFC and true food allergy. While these values are relatively high, they may serve as an appropriate substitute for food challenges in clinical and research settings.

Treatment of eosinophilic esophagitis in the pediatric patient: an evidence-based approach

Eosinophilic esophagitis (EoE) is a unique form of non-IgE-mediated food allergy characterized by esophageal eosinophilic infiltration that commonly causes dysphagia and food impaction in children and adolescents. Assessing the efficacy of dietary restrictions or drug therapies to achieve clinical and histologic resolution of EoE through randomized controlled trials and meta-analyses has resulted in new evidence-based guidelines. Avoiding food triggers is the only therapy targeting the cause of the disease. None of the currently available food allergy tests adequately predict food triggers for EoE. Exclusively feeding with an amino acid-based elemental diet and empiric six-food elimination diet (avoiding the six foods most commonly related with food allergy) has consistently provided the best cure rates, but their high level of restriction and need for multiple endoscopies are deterrents for implementation. Simpler and less restrictive empirical methods, like a four-food (milk, gluten-containing cereals, egg, legumes) or a two-food (milk and gluten) elimination diet, show encouraging results. Proton pump inhibitors are currently a first-line treatment, achieving histological remission and improvement of symptoms in 54.1 and 64.9% of pediatric EoE patients, respectively. The efficacy of topical corticosteroids in EoE assessed in several trials and summarized in meta-analyses indicates that budesonide and fluticasone propionate are significantly superior to placebos, both in decreasing eosinophil mucosal infiltration and in relieving symptoms. Owing to differences in drug delivery, viscous budesonide formulas seem to be the best pharmacological therapy for EoE.

CONCLUSION

Applying evidence-based therapies and a practical management algorithm provide an effective control of EoE. What is Known: • Eosinophilic esophagitis (EoE) now constitutes the main cause of dysphagia and food impaction in children, adolescents, and young adults. • Its chronic course and frequent progression to subepithelial fibrosis leading to strictures and narrow-caliber esophagus indicate the need for treatment. What is New: • Therapeutic goals in children with EoE include resolution of esophageal symptoms, to cure esophageal inflammation (mucosal healing) and restore a proper esophageal caliber in case of fibrostenotic endoscopic findings. Avoiding iatrogenic drug effects and nutritional deficiencies, as well as maintaining an adequate quality of life, is also essential. • Novel evidence-based guidelines, endorsed by several European scientific societies, incorporate recent advances in knowledge from several randomized controlled trials and systematic reviews to provide the best standard of care to pediatric patients, by following simple management algorithms.

Early introduction of allergenic foods for the prevention of food allergy from an Asian perspective-An Asia Pacific Association of Pediatric Allergy, Respirology & Immunology (APAPARI) consensus statement

Emerging evidence for the early introduction of allergenic foods for the prevention of food allergies, such as peanut allergy in Western populations, has led to the recent publication of guidelines in the USA and Europe recommending early peanut introduction for high-risk infants with severe eczema or egg allergy. Peanut allergy is, however, much less prevalent in Asia compared to the West. Varying patterns of food allergy are seen even within Asian countries-such as a predominance of wheat allergy in Japan and Thailand and shellfish allergy in Singapore and the Philippines. Customs and traditions, such as diet and infant feeding practices, also differ between Asian populations. Hence, there are unique challenges in adapting guidelines on early allergenic food introduction to the Asian setting. In this paper, we review the evidence and discuss the possible approaches to guide the timely introduction of allergenic food in high-risk infants in Asia.

Human Immune Monitoring Techniques during Food Allergen Immunotherapy

PURPOSE OF REVIEW

Encouraging results from recent food allergen immunotherapy clinical trials indicate that the immune system plays an essential role in peripheral tolerance to food allergen. Thus, the monitoring of changes in immune responses and their possible correlation with clinical outcome in allergic patients receiving immunotherapies could theoretically serve as surrogate markers and be harnessed as rationale for food allergen immunotherapy development.

RECENT FINDINGS

A shift towards antigen specificity in recent assays has provided a solid foundation for the elucidation of cellular mechanisms involved in food allergen immunotherapy as well as the tracking of allergen-specific immune cells. In this review, we overview the current challenges and technologies used in immune monitoring during immunotherapy in allergic patients with a focus on cell-mediated immunity. We also discuss critical steps involved in some of the cellular immune assays utilized in clinical trials.

Implementation of a Standardized Clinical Assessment and Management Plan (SCAMP) for Food Challenges

BACKGROUND

Oral food challenges (OFCs) are routinely used to confirm ongoing food allergy. Serum-specific IgE (sIgE) and skin prick testing (SPT) are imperfect predictors of which patients will pass OFCs.

OBJECTIVE

The objective of this study was to describe the design and implementation of a Standardized Clinical Assessment and Management Plan (SCAMP) to study and iteratively improve sIgE and SPT thresholds to determine when and where to conduct OFCs for patients.

METHODS

Allergists consulted recommended sIgE and SPT thresholds when ordering challenges although diversions were permitted. Criteria were iteratively improved after periodic analyses of challenge outcome and diversions.

RESULTS

Over 3 years, allergists ordered 2368 food challenges for 1580 patients with histories of IgE-mediated reactions to food: 1386 in an outpatient clinic and 945 in a higher resource infusion center. Reactions to challenge were observed in 13% of clinic and 23% of infusion center challenges. Six patients challenged in clinic required treatment with epinephrine compared with 22 in the infusion center. The need for epinephrine was more common in patients with asthma-5% of asthmatic patients required epinephrine compared with 1% of nonasthmatic patients (P < .01). Recommended sIgE and SPT thresholds were incrementally changed and, using the control chart methodology, a significant decrease was noted in the proportion of challenges ordered in the higher resource location.

CONCLUSIONS

By setting and continually refining sIgE and SPT recommendations using the SCAMP method, allergists can better determine the risk of severe reaction and triage patients to the appropriate setting for an OFC.

A new framework for the interpretation of IgE sensitization tests

IgE sensitization tests, such as skin prick testing and serum-specific IgE, have been used to diagnose IgE-mediated clinical allergy for many years. Their prime drawback is that they detect sensitization which is only loosely related to clinical allergy. Many patients therefore require provocation tests to make a definitive diagnosis; these are often expensive and potentially associated with severe reactions. The likelihood of clinical allergy can be semi-quantified from an IgE sensitization test results. This relationship varies though according to the patients' age, ethnicity, nature of the putative allergic reaction and coexisting clinical diseases such as eczema. The likelihood of clinical allergy can be more precisely estimated from an IgE sensitization test result, by taking into account the patient's presenting features (pretest probability). The presence of each of these patient-specific factors may mean that a patient is more or less likely to have clinical allergy with a given test result (post-test probability). We present two approaches to include pretest probabilities in the interpretation of results. These approaches are currently limited by a lack of data to allow us to derive pretest probabilities for diverse setting, regions and allergens. Also, cofactors, such as exercise, may be necessary for exposure to an allergen to result in an allergic reaction in specific IgE-positive patients. The diagnosis of IgE-mediated allergy is now being aided by the introduction of allergen component testing which may identify clinically relevant sensitization. Other approaches are in development with basophil activation testing being closest to clinical application.

Risk and safety requirements for diagnostic and therapeutic procedures in allergology: World Allergy Organization Statement

One of the major concerns in the practice of allergy is related to the safety of procedures for the diagnosis and treatment of allergic disease. Management (diagnosis and treatment) of hypersensitivity disorders involves often intentional exposure to potentially allergenic substances (during skin testing), deliberate induction in the office of allergic symptoms to offending compounds (provocation tests) or intentional application of potentially dangerous substances (allergy vaccine) to sensitized patients. These situations may be associated with a significant risk of unwanted, excessive or even dangerous reactions, which in many instances cannot be completely avoided. However, adverse reactions can be minimized or even avoided if a physician is fully aware of potential risk and is prepared to appropriately handle the situation. Information on the risk of diagnostic and therapeutic procedures in allergic diseases has been accumulated in the medical literature for decades; however, except for allergen specific immunotherapy, it has never been presented in a systematic fashion. Up to now no single document addressed the risk of the most commonly used medical procedures in the allergy office nor attempted to present general requirements necessary to assure the safety of these procedures. Following review of available literature a group of allergy experts within the World Allergy Organization (WAO), representing various continents and areas of allergy expertise, presents this report on risk associated with diagnostic and therapeutic procedures in allergology and proposes a consensus on safety requirements for performing procedures in allergy offices. Optimal safety measures including appropriate location, type and required time of supervision, availability of safety equipment, access to specialized emergency services, etc. for various procedures have been recommended. This document should be useful for allergists with already established practices and experience as well as to other specialists taking care of patients with allergies.

Food allergy: Past, present and future

Hippocrates is often credited with first recognizing that food could be responsible for adverse symptoms and even death in some individuals, but it was not until the seminal observations by Prausnitz that the investigation of food allergy was viewed on a more scientific basis. In the first half of the 20th century, there were periodic reports in the medical literature describing various food allergic reactions. In the mid- to late- 1970's, the studies of Charles May and colleagues began to penetrate the medical world's skepticism about the relevance of food allergy and how to diagnose it, since standard skin testing was known to correlate poorly with clinical symptoms. With May's introduction of the double-blind placebo-controlled oral food challenge, the study of food allergy became evidence-based and exponential strides have been made over the past four decades in the study of basic immunopathogenic mechanisms and natural history, and the diagnosis and management of food allergies. Today IgE- and non-IgE-mediated food allergic disorders are well characterized and efforts to treat these allergies by various immunotherapeutic strategies are well under way.

Overview of food allergy diagnosis

Food allergy is a condition with significant social and economic impact and a topic of intense concern for scientists and clinicians alike. Worldwide, over 220 million people suffer from some form of food allergy, but the number reported is just the tip of the iceberg. Recent years have brought new perspectives in diagnosing food allergy. Elucidating incriminated immunological mechanisms, along with drawing the clinical phenotype of food hypersensitivity reactions ensures an accurate diagnosis of food allergy. Moreover, molecular based allergy diagnosis, which is increasingly used in routine care, is a stepping-stone to improved management of food allergy patients. The aim of this review is to summarize the topic of IgE-mediated food allergy from the perspective of current diagnostic methods.

Is it possible to make a diagnosis of raw, heated, and baked egg allergy in children using cutoffs? A systematic review

The diagnosis of IgE-mediated egg allergy lies both on a compatible clinical history and on the results of skin prick tests (SPTs) and IgEs levels. Both tests have good sensitivity but low specificity. For this reason, oral food challenge (OFC) is the ultimate gold standard for the diagnosis. The aim of this study was to systematically review the literature in order to identify, analyze, and synthesize the predictive value of SPT and specific IgEs both to egg white and to main egg allergens and to review the cutoffs suggested in the literature. A total of 37 articles were included in this systematic review. Studies were grouped according to the degree of cooking of the egg used for OFC, age, and type of allergen used to perform the allergy workup. In children <2 years, raw egg allergy seems very likely when SPTs with egg white extract are ≥4 mm or specific IgEs are ≥1.7 kUA /l. In children ≥2 years, OFC could be avoided when SPTs with egg white extract are ≥10 mm or prick by prick with egg white is ≥14 mm or specific IgE is ≥7.3 kUA /l. Likewise, heated egg allergy can be diagnosed if SPTs with egg white extract are >5 and >11 mm in children <2 and ≥2 years, respectively. Further and better-designed studies are needed to determine the remaining diagnostic cutoff of specific IgE and SPT for heated and baked egg allergy.

Assessment of Allergy to Milk, Egg, Cod, and Wheat in Swedish Schoolchildren: A Population Based Cohort Study

Objectives

Knowledge about the prevalence of allergies to foods in childhood and adolescence is incomplete. The purpose of this study was to investigate the prevalence of allergies to milk, egg, cod, and wheat using reported data, clinical examinations, and double-blind placebo-controlled food challenges, and to describe the phenotypes of reported food hypersensitivity in a cohort of Swedish schoolchildren.

Methods

In a population-based cohort of 12-year-old children, the parents of 2612 (96% of invited) completed a questionnaire. Specific IgE antibodies to foods were analyzed in a random sample (n=695). Children reporting complete avoidance of milk, egg, cod, or wheat due to perceived hypersensitivity and without physician-diagnosed celiac disease were invited to undergo clinical examination that included specific IgE testing, a celiac screening test, and categorization into phenotypes of food hypersensitivity according to preset criteria. Children with possible food allergy were further evaluated with double-blind challenges.

Results

In this cohort, the prevalence of reported food allergy to milk, egg, cod, or wheat was 4.8%. Food allergy was diagnosed in 1.4% of the children after clinical evaluation and in 0.6% following double-blind placebo-controlled food challenge. After clinical examination, children who completely avoided one or more essential foods due to perceived food hypersensitivity were categorized with the following phenotypes: allergy (29%), outgrown allergy (19%), lactose intolerance (40%), and unclear (12%).

Conclusions

There was a high discrepancy in the prevalence of allergy to milk, egg, cod and wheat as assessed by reported data, clinical evaluation, and double-blind food challenges. Food hypersensitivity phenotyping according to preset criteria was helpful for identifying children with food allergy.

Diagnosis and treatment of pediatric food allergy: an update

The prevalence of pediatric food allergy and anaphylaxis has increased in the last decades, especially in westernized countries where this emerging phenomenon was marked as a "second wave" of the allergic epidemic. Over recent years great advances have been achieved in the field of in vitro allergy testing and component-resolved diagnosis has increasingly entered clinical practice. Testing for allergen components can contribute to a more precise diagnosis by discriminating primary from cross-reactive sensitizations and assessing the risk of severe allergic reactions.The basic concept of the management of food allergy in children is also changing. Avoidance of the offending food is still the mainstay for disease management, especially in primary health care settings, but it severely affects the patients' quality of life without reducing the risk of accidental allergic reactions. There is a growing body of evidence to show that specific oral tolerance induction can represent a promising treatment option for food allergic patients. In parallel, education of food allergic patients and their caregivers as well as physicians about anaphylaxis and its treatment is becoming recognized a fundamental need. International guidelines have recently integrated these new evidences and their broad application all over Europe represents the new challenge for food allergy specialists.

Food allergy: a practice parameter update-2014

This parameter was developed by the Joint Task Force on Practice Parameters, representing the American Academy of Allergy, Asthma & Immunology (AAAAI); the American College of Allergy, Asthma & Immunology (ACAAI); and the Joint Council of Allergy, Asthma & Immunology (JCAAI). The AAAAI and the ACAAI have jointly accepted responsibility for establishing "Food Allergy: A practice parameter update-2014." This is a complete and comprehensive document at the current time. The medical environment is a changing one, and not all recommendations will be appropriate for all patients. Because this document incorporated the efforts of many participants, no single individual, including those who served on the Joint Task Force, is authorized to provide an official AAAAI or ACAAI interpretation of these practice parameters. Any request for information about or an interpretation of these practice parameters by the AAAAI or ACAAI should be directed to the Executive Offices of the AAAAI, ACAAI, and JCAAI. These parameters are not designed for use by pharmaceutical companies in drug promotion.

Recommendations for the allergy management in the primary care

The majority of patients seeking medical advice for allergic diseases are first seen in a primary care setting. Correct diagnosis with identification of all offending allergens is an absolute prerequisite for appropriate management of allergic disease by the general practitioner. Allergy diagnostic tests recommended for use in primary care are critically reviewed in accordance with the significant workload in a primary care setting. Simplified pathways for recognition and diagnosis of allergic diseases are proposed, that should be further adapted to local (national) conditions.

Recent advances on diagnosis and management of childhood asthma and food allergies

The epidemic of childhood allergic disorders has been associated to the decline of infectious disease. However, exposure to many triggers (airborne viruses, tobacco smoke, pollution, indoor allergens, etc.) contribute to the disease. Breast feeding practices, nutrition, dietary and obesity also play a multifaceted role in shaping the observed worldwide trends of childhood allergies. Guidelines for treatment are available, but their implementation is suboptimal. Then developed countries are slowing learning integrating the development of suitable guidelines with implementation plans. Awareness, psychosocial and family factors strongly influence asthma and food allergy control. Moreover, monitoring tools are necessary to facilitate self-management. By taking into consideration these and many other pragmatic aspects, national public health programs to control the allergic epidemic have been successful in reducing its impact and trace the need for future research in the area.

The natural history of IgE-mediated food allergy: can skin prick tests and serum-specific IgE predict the resolution of food allergy?

IgE-mediated food allergy is a transient condition for some children, however there are few indices to predict when and in whom food allergy will resolve. Skin prick test (SPT) and serum-specific IgE levels (sIgE) are usually monitored in the management of food allergy and are used to predict the development of tolerance or persistence of food allergy. The aim of this article is to review the published literature that investigated the predictive value of SPT and sIgE in development of tolerance in children with a previous diagnosis of peanut, egg and milk allergy. A systematic search identified twenty-six studies, of which most reported SPT or sIgE thresholds which predicted persistent or resolved allergy. However, results were inconsistent between studies. Previous research was hampered by several limitations including the absence of gold standard test to diagnose food allergy or tolerance, biased samples in retrospective audits and lack of systematic protocols for triggering re-challenges. There is a need for population-based, prospective studies that use the gold standard oral food challenge (OFC) to diagnose food allergy at baseline and follow-up to develop SPT and sIgE thresholds that predict the course of food allergy.

Food allergy diagnosis and therapy: where are we now?

Food allergy is a growing worldwide epidemic that adversely effects up to 10% of the population. Causes and risk factors remain unclear and diagnostic methods are imprecise. There is currently no accepted treatment for food allergy. Therefore, there is an imminent need for greater understanding of food allergies, revised diagnostics and development of safe, effective therapies. Oral immunotherapy provides a particularly promising avenue, but is still highly experimental and not ready for clinical use.

Testing children for allergies: why, how, who and when: an updated statement of the European Academy of Allergy and Clinical Immunology (EAACI) Section on Pediatrics and the EAACI-Clemens von Pirquet Foundation

Allergic diseases are common in childhood and can cause a significant morbidity and impaired quality-of-life of the children and their families. Adequate allergy testing is the prerequisite for optimal care, including allergen avoidance, pharmacotherapy and immunotherapy. Children with persisting or recurrent or severe symptoms suggestive for allergy should undergo an appropriate diagnostic work-up, irrespective of their age. Adequate allergy testing may also allow defining allergic trigger in common symptoms. We provide here evidence-based guidance on when and how to test for allergy in children based on common presenting symptoms suggestive of allergic diseases.

Food allergy and anaphylaxis in pediatrics: update 2010-2012

This review highlights the progress made in food allergy (FA) and anaphylaxis research in pediatrics published in the journal Pediatric Allergy and Immunology since 2010. Putative risk factors for FA are as follows: a family history of allergic disease, particularly in the mother, low birth order, season of birth, and severe atopic eczema. Obstetric practices, antibiotic use, and home environment are factors deserving further research. Diagnostic decision levels and component-specific IgE are useful in the diagnosis of FA; however, oral food challenges remain the gold standard and may also be a means to reduce parental anxiety and to improve education. Oral immunotherapy studies show promise in increasing the threshold of reactivity of allergic patients and therefore improving their quality of life. In single-nut-allergic patients, introduction of other nuts allows broadening the diet and thus reducing the psychological impact of allergen avoidance. Nutritional deficiencies are not uncommon in food-allergic children and should be specifically assessed. The prescription of injectable adrenaline is still insufficient and not consistent among practitioners, requiring improved training and implementation of guidelines. Current research into the epidemiology and immunological mechanisms of FA and tolerance will enable us to devise strategies to both prevent and treat food allergies.

Oral food challenge: safety, adherence to guidelines and predictive value of skin prick testing

BACKGROUND

The diagnostic gold standard of food allergy is the oral food challenge (OFC). Data on severe reactions and drug use during OFC are scarce. Our aims were (i) to investigate the prevalence and spectrum of reactions' severity during OFC and to assess drug use and epinephrine use in anaphylaxis due to OFC; (ii) to investigate the predictive value of the skin prick test wheal size for the outcome of OFCs.

METHODS

A retrospective charts review of children undergoing OFC at three Allergy Centres between January 2007 and December 2008 was performed.

RESULTS

A total of 544 OFCs were analysed. Most frequently involved foods were egg, milk and wheat. 254/526 (48.3%) were positive. 167 (65.7%) were defined mild reactions, 81 (31.9%) multiorgan reactions and 6 (2.4%) anaphylaxis. No patients had cardiovascular symptoms. Data on treatments were available in 98.8% OFCs. In half of them antihistamines were used vs. 10% cases in which steroids were preferred. Six children (2.4%) were treated with Epinephrine inhalation, 5 (2%) with beta-2 inhalation, 8 (3.1%) with steroid inhalation. One child was treated with IM Epinephrine + IV fluids. Skin prick tests predictive cut-off were 9 mm for albumen, 7 for yolk, 13 for fresh albumen, 10 for α-lactalbumin, seven for casein, eight for β-lactoglobulin, 20 for cow's milk and 10 for fresh cow's milk.

CONCLUSION

OFCs performed in controlled settings by expert Allergists are safe. Consideration needs to be given as to whether the Anaphylaxis' Guideline need to be modified when applied in treating patients undergoing OFC.

Relationship between red meat allergy and sensitization to gelatin and galactose-α-1,3-galactose

BACKGROUND

We have observed patients clinically allergic to red meat and meat-derived gelatin.

OBJECTIVE

We describe a prospective evaluation of the clinical significance of gelatin sensitization, the predictive value of a positive test result, and an examination of the relationship between allergic reactions to red meat and sensitization to gelatin and galactose-α-1,3-galactose (α-Gal).

METHODS

Adult patients evaluated in the 1997-2011 period for suspected allergy/anaphylaxis to medication, insect venom, or food were skin tested with gelatin colloid. In vitro (ImmunoCAP) testing was undertaken where possible.

RESULTS

Positive gelatin test results were observed in 40 of 1335 subjects: 30 of 40 patients with red meat allergy (12 also clinically allergic to gelatin), 2 of 2 patients with gelatin colloid-induced anaphylaxis, 4 of 172 patients with idiopathic anaphylaxis (all responded to intravenous gelatin challenge of 0.02-0.4 g), and 4 of 368 patients with drug allergy. Test results were negative in all patients with venom allergy (n = 241), nonmeat food allergy (n = 222), and miscellaneous disorders (n = 290). ImmunoCAP results were positive to α-Gal in 20 of 24 patients with meat allergy and in 20 of 22 patients with positive gelatin skin test results. The results of gelatin skin testing and anti-α-Gal IgE measurements were strongly correlated (r = 0.46, P < .01). α-Gal was detected in bovine gelatin colloids at concentrations of approximately 0.44 to 0.52 μg/g gelatin by means of inhibition RIA.

CONCLUSION

Most patients allergic to red meat were sensitized to gelatin, and a subset was clinically allergic to both. The detection of α-Gal in gelatin and correlation between the results of α-Gal and gelatin testing raise the possibility that α-Gal IgE might be the target of reactivity to gelatin. The pathogenic relationship between tick bites and sensitization to red meat, α-Gal, and gelatin (with or without clinical reactivity) remains uncertain.

ICON: food allergy

Food allergies can result in life-threatening reactions and diminish quality of life. In the last several decades, the prevalence of food allergies has increased in several regions throughout the world. Although more than 170 foods have been identified as being potentially allergenic, a minority of these foods cause the majority of reactions, and common food allergens vary between geographic regions. Treatment of food allergy involves strict avoidance of the trigger food. Medications manage symptoms of disease, but currently, there is no cure for food allergy. In light of the increasing burden of allergic diseases, the American Academy of Allergy, Asthma & Immunology; European Academy of Allergy and Clinical Immunology; World Allergy Organization; and American College of Allergy, Asthma & Immunology have come together to increase the communication of information about allergies and asthma at a global level. Within the framework of this collaboration, termed the International Collaboration in Asthma, Allergy and Immunology, a series of consensus documents called International Consensus ON (ICON) are being developed to serve as an important resource and support physicians in managing different allergic diseases. An author group was formed to describe the natural history, prevalence, diagnosis, and treatment of food allergies in the context of the global community.