Comparison of commercial allergen extract with various milk products of skin prick tests in diagnosing cow's milk protein allergy

Introduction: In this study, we aimed to solve the incompatibilities between the skin prick test (SPT) result and the clinical picture encountered among patients. Thus, we used various milk products (raw, ultrahigh temperature [UHT], and pasteurized cow's milk) with commercial milk allergen extract in patients we think may have cow's milk protein allergy (CMPA) and made a comparison among the milk types. Methods: This study was conducted retrospectively between February 1, 2019, to June 1, 2019, at a pediatric allergy polyclinic of the university training/research hospital. A pair of 79 individuals, as control and patient groups, ages between 1 month and 21 years who were presented with a suspicion of CMPA and defined with SPT and/or allergen-specific immunoglobulin E (IgE) levels were included in the study. Allergen-specific IgE tests (specific IgE cow's milk, β-lactoglobulin, α-lactalbumin, casein) were evaluated. SPT was performed with fresh/raw, UHT, and pasteurized (daily) cow's milk besides the standard used commercial extract. Results: In the group included in the study and defined as IgE-mediated CMPA, 52.9% of the 79 patients were boys (n = 46), 47.1% were girls (n = 33), and the median age was 6 months (5.0-8.0 months). In the group of specific IgE cow's milk reaction that was sought, frequency and wheal (induration) size of SPT reaction to fresh/raw milk was also found to be statistically significant between positive- and negative-reaction groups, not detected against other milk products. The area under the curve for the diagnostic value of fresh milk was 93.1%. For the cutoff value of 2.50 mm, 88.1% sensitivity and 90.8% specificity were determined. In the group of specific IgE β-lactoglobulin reaction searched, there was a statistically significant difference in the frequency of SPT positivity and wheal size against UHT, fresh, and daily/pasteurized milk between positive and negative reaction groups. When the correlations of the mean induration axis in the tests were examined, it was found that, among raw milk, daily milk, cow's milk allergen extract, and UHT milk, a strong positive correlation was also statistically significant. Conclusion: The positivity that could not be detected with SPT when using allergen extract in a patient with positive specific IgE cow's milk result in the clinic can be detected with SPT made with fresh (raw) milk, which can be an alternative. In addition, specific IgE β-lactoglobulin seems to be the most compatible with the SPT wheal size (induration) of other milk types rather than extract. Comparative studies of SPT allergen extracts and various milk types used in the diagnosis of CMPA are very scarce in the literature, and more studies are needed on this subject.

Peanut allergy in an adult following cardiac transplant from a non-atopic donor

We present a 62-year-old woman with severe heart failure and who required cardiac transplantation. On postoperative day 22, she experienced anaphylaxis to peanut, with an elevated peanut-specific immunoglobulin E level. This case highlights the differential diagnosis of posttransplantation anaphylaxis as well as the appropriate evaluation.

Comprehensive Analysis of the Structure and Allergenicity Changes of Seafood Allergens Induced by Non-Thermal Processing: A Review

Seafood allergy, mainly induced by fish, shrimp, crab, and shellfish, is a food safety problem worldwide. The non-thermal processing technology provides a new method in reducing seafood allergenicity. Based on the structural and antigenic properties of allergenic proteins, this review introduces current methods for a comprehensive analysis of the allergenicity changes of seafood allergens induced by non-thermal processing. The IgE-binding capacities/immunoreactivity of seafood allergens are reduced by the loss of conformation during non-thermal processing. Concretely, the destruction of native structure includes degradation, aggregation, uncoiling, unfolding, folding, and exposure, leading to masking of the epitopes. Moreover, most studies rely on IgE-mediated assays to evaluate the allergenic potential of seafood protein. This is not convincing enough to assess the effect of novel food processing techniques. Thus, further studies must be conducted with functional assays, in vivo assays, animal trials, simulated digestion, and intestinal microflora to strengthen the evidence. It also enables us to better identify the effects of non-thermal processing treatment, which would help further analyze its mechanism.

Absolute Quantitation of Serum Antibody Reactivity Using the Richards Growth Model for Antigen Microspot Titration

In spite of its pivotal role in the characterization of humoral immunity, there is no accepted method for the absolute quantitation of antigen-specific serum antibodies. We devised a novel method to quantify polyclonal antibody reactivity, which exploits protein microspot assays and employs a novel analytical approach. Microarrays with a density series of disease-specific antigens were treated with different serum dilutions and developed for IgG and IgA binding. By fitting the binding data of both dilution series to a product of two generalized logistic functions, we obtained estimates of antibody reactivity of two immunoglobulin classes simultaneously. These estimates are the antigen concentrations required for reaching the inflection point of thermodynamic activity coefficient of antibodies and the limiting activity coefficient of antigen. By providing universal chemical units, this approach may improve the standardization of serological testing, the quality control of antibodies and the quantitative mapping of the antibody-antigen interaction space.

IgE-Mediated food allergy: Current diagnostic modalities and novel biomarkers with robust potential

Food allergy (FA) is a serious public health issue afflicting millions of people globally, with an estimated prevalence ranging from 1-10%. Management of FA is challenging due to overly restrictive diets and the lack of diagnostic approaches with high accuracy and prediction. Although measurement of serum-specific antibodies combined with patient medical history and skin prick test is a useful diagnostic tool, it is still an imprecise predictor of clinical reactivity with a high false-positive rate. The double-blind placebo-controlled food challenge represents the gold standard for FA diagnosis; however, it requires large healthcare and involves the risk of acute onset of allergic reactions. Improvement in our understanding of the molecular mechanism underlying allergic disease pathology, development of omics-based methods, and advances in bioinformatics have boosted the generation of a number of robust diagnostic biomarkers of FA. In this review, we discuss how traditional diagnostic modalities guide appropriate diagnosis and management of FA in clinical practice, as well as uncover the potential of the latest biomarkers for the diagnosis, monitoring, and prediction of FA. We also raise perspectives for precise and targeted medical intervention to fill the gap in the diagnosis of FA.

Halting the March: Primary Prevention of Atopic Dermatitis and Food Allergies

Atopic dermatitis (AD) is one of the most common inflammatory skin conditions, affecting 15% to 30% of children and 2% to 10% of adults. Population-based studies suggest that having AD is associated with subsequent development of other atopic diseases, in what is known as the "atopic march." We will provide an overview of studies that investigate primary prevention strategies for the first 2 diseases in the march, namely, AD and food allergies (FA). These strategies include emollients, breastfeeding, microbial exposures, probiotics, vitamin D and UV light, water hardness, and immunotherapy. Some studies, including randomized controlled trials on emollients and microbial supplementation, have found encouraging results; however, the evidence remains limited and contradictory. With regard to breastfeeding, microbial and lifestyle exposures, vitamin D and UV light, water hardness, and immunotherapy, the lack of randomized controlled trials makes it difficult to draw definitive conclusions. Current American Academy of Pediatrics guidelines support the idea that breastfeeding for 3 to 4 months can decrease AD incidence in children less than 2 years old. Recommendations regarding a direct relationship between breastfeeding on FA, however, cannot be made because of insufficient data. Regarding microbial supplementation, most guidelines do not recommend probiotics or prebiotics for the purpose of preventing allergic diseases because of limited evidence. Before definitive conclusions can be made regarding these interventions, more well-designed, longitudinal, and randomized controlled trials, particularly in at-risk populations, are required.

Clinical Management of Seafood Allergy

Seafood plays an important role in human nutrition and health. A good patient workup and sensitive diagnostic analysis of IgE antibody reactivity can distinguish between a true seafood allergy and other adverse reactions generated by toxins or parasites contaminating ingested seafood. The 2 most important seafood groupings include the fish and shellfish. Shellfish, in the context of seafood consumption, constitutes a diverse group of species subdivided into crustaceans and mollusks. The prevalence of shellfish allergy seems to be higher than that of fish allergy, with an estimate of up to 3% in the adult population and fin fish allergy prevalence of approximately 1%. Clinical evaluation of the seafood-allergic patient involves obtaining a detailed history and obtaining in vivo and/or in vitro testing with careful interpretation of results with consideration of cross-reactivity features of the major allergens. Oral food challenge is useful not only for the diagnosis but also for avoiding unnecessary dietary restrictions. In this review, we highlight some of the recent reports to provide solid clinical and laboratory tools for the differentiation of fish allergy from shellfish allergy, enabling best treatment and management of these patients.

IgE-Mediated Fish Allergy in Children

Fish allergy constitutes a severe problem worldwide. Its prevalence has been calculated as high as 7% in paediatric populations, and in many cases, it persists into adulthood with life-threatening signs and symptoms. The following review focuses on the epidemiology of Immunoglobulin E (IgE)-mediated fish allergy, its pathogenesis, clinical manifestations, and a thorough approach to diagnosis and management in the paediatric population. The traditional approach for managing fish allergy is avoidance and rescue medication for accidental exposures. Food avoidance poses many obstacles and is not easily maintained. In the specific case of fish, food is also not the only source of allergens; aerosolisation of fish proteins when cooking is a common source of highly allergenic parvalbumin, and elimination diets cannot prevent these contacts. Novel management approaches based on immunomodulation are a promising strategy for the future of these patients.

The use of microarray and other multiplex technologies in the diagnosis of allergy

OBJECTIVE

To give an overview and describe the strengths and weaknesses of immunoglobulin E (IgE) microarray and other multiplex assays that have been developed and are being used for allergy diagnostics.

DATA SOURCES

Queries for IgE microarray and multiplex assays were conducted with PubMed and Google Scholar, searching for primary articles and review papers.

STUDY SELECTIONS

We focused on articles written in English on commercially available IgE multiplex assays that were reported in the allergy and immunology literature.

RESULTS

Several commercial IgE assays that use microarray or other multiplex technology have been developed, and some have been implemented into clinical practice in Europe and Asia, with the Immuno Solid-Phase Allergen Chip being the most widely studied. Results of these assays generally correlate with results using "singleplex" IgE assays (eg, ImmunoCAP), though there can be variability among products and among allergens. A strength of the microarray technology is that IgE to a large number of allergens can be detected simultaneously in a single test, and only a small amount of patient serum is required. Cost, inadequate sensitivity under some scenarios, and difficulties with data interpretation, in some cases of 100 or more allergens, can be limitations.

CONCLUSION

IgE microarray assays are already a valuable tool in research applications. These assays, and also other forms of IgE multiplex assays, are likely to play an important role in the clinical practice of allergy in the future. Additional studies focused on clinical outcomes, and the development of more targeted allergen panels could facilitate increased clinical use.

Appropriate age range for introduction of complementary feeding into an infant's diet

Following a request from the European Commission, the Panel on Nutrition, Novel Foods and Food Allergens (NDA) revised its 2009 Opinion on the appropriate age for introduction of complementary feeding of infants. This age has been evaluated considering the effects on health outcomes, nutritional aspects and infant development, and depends on the individual's characteristics and development. As long as foods have an age-appropriate texture, are nutritionally appropriate and prepared following good hygiene practices, there is no convincing evidence that at any age investigated in the included studies (< 1 to < 6 months), the introduction of complementary foods (CFs) is associated with adverse health effects or benefits (except for infants at risk of iron depletion). For nutritional reasons, the majority of infants need CFs from around 6 months of age. Infants at risk of iron depletion (exclusively breastfed infants born to mothers with low iron status, or with early umbilical cord clamping (< 1 min after birth), or born preterm, or born small-for-gestational age or with high growth velocity) may benefit from earlier introduction of CFs that are a source of iron. The earliest developmental skills relevant for consuming pureed CFs can be observed between 3 and 4 months of age. Skills for consuming finger foods can be observed in some infants at 4 months, but more commonly at 5-7 months. The fact that an infant may be ready from a neurodevelopmental perspective to progress to a more diversified diet before 6 months of age does not imply that there is a need to introduce CFs. There is no reason to postpone the introduction of potentially allergenic foods (egg, cereals, fish and peanut) to a later age than that of other CFs as far as the risk of developing atopic diseases is concerned. Regarding the risk of coeliac disease, gluten can be introduced with other CFs.

Food Allergen Sensitisation Patterns in Omani Patients with Allergic Manifestations

Objectives

This study aimed to evaluate the relationship between food allergen sensitisation patterns and allergic manifestations in Omani patients and highlight the importance of specific immunoglobulin E (IgE) testing.

Methods

This retrospective study included all patients referred due to allergic manifestations to the Sultan Qaboos University Hospital (SQUH), Muscat, Oman, from November 2012 to November 2016. Specific IgE blood testing was performed to determine sensitisation to common foods known to cause allergic reactions.

Results

A total of 164 patients were referred to SQUH over the study period, with 35.4% presenting with one allergic manifestation, 48.8% with 2-3 and 15.9% presenting with more than three manifestations. There was a family history of allergies in 70.7% of patients. Eosinophil counts and total and specific IgE levels were elevated in 18.9%, 54.9% and 73.2% of patients, respectively. Patients demonstrated sensitisation to cow milk (47.6%), wheat (41.5%), chicken eggs (34.8%), mixed tree nuts (34.1%), lentils (33.5%), peanuts (32.9%), soy (32.3%), shrimp (23.2%) and fish (15.2%). Overall, 19.5% were sensitised to a single allergen, 14% were sensitised to 2-3 and 39.6% were sensitised to more than three allergens. Almost one-third (29.3%) of patients suffered from food-induced anaphylaxis, of which 85.4% were prescribed self-injectable adrenaline.

Conclusion

To the best of the authors' knowledge, this study is the first to describe food allergen sensitisation patterns among Omani patients with allergic manifestations. In conjunction with clinical symptoms, the correct interpretation of specific IgE levels is important to diagnose food allergies and make safe decisions about reintroducing foods.

Sensitization profiles to hazelnut allergens across the United States

BACKGROUND

Measurement of IgE antibody to hazelnut components can aid in the prediction of allergic responses to the food.

OBJECTIVE

To investigate the association between patient demographics (age, location) and patterns of allergic sensitization to hazelnut components across the United States and to investigate the degree of correlation between hazelnut sensitization with sensitization to other tree nuts, peanuts, and their components.

METHODS

Serum samples from 10,503 individuals with hazelnut extract specific IgE (sIgE) levels of 0.35 kU_A/L or higher were analyzed for IgE antibodies to Cor a 1, 8, 9, and 14 by ImmunoCAP. A subset of these patients were analyzed for IgE antibodies to peanut, walnut, and cashew nut IgE along with associated components.

RESULTS

Among hazelnut sensitized individuals, children (<3 years old) were predominantly sensitized to Cor a 9 and Cor a 14. Conversely, Cor a 1 sIgE sensitization was much higher in adults than children, especially in the Northeastern United States. Cor a 8 sensitization was relatively constant (near 10%) across all ages. Cosensitization of hazelnut with other tree nuts and peanuts was related to correlation of IgE concentrations of individual component families.

CONCLUSION

We conclude that sensitization to individual hazelnut components is highly dependent on age and/or geographic location. Component correlations suggest that cosensitization to hazelnut and walnut may be caused by their pathogenesis-related protein 10 allergens, nonspecific lipid transfer proteins, or seed storage proteins, whereas hazelnut and peanut cosensitization is more often caused by cross-reactivity of pathogenesis-related protein 10 (Cor a 1 and Ara h 8) and nonspecific lipid transfer proteins (Cor a 8 and Ara h 9).

The impact of oral food challenges for food allergy on quality of life: A systematic review

BACKGROUND

Food allergy significantly impairs health-related quality of life (HRQL). Currently, it is still unknown whether diagnostic interventions for food allergy improve HRQL. We aim to assess the impact of diagnostic interventions for food allergy on HRQL.

METHODS

A systematic search was performed in MEDLINE, Embase, Cochrane Library, and CINAHL focused on patients with a (suspected) food allergy who underwent diagnostic interventions (ie, skin prick test, specific IgE, or oral food challenges [OFC]) and in whom HRQL was assessed. The mean difference between HRQL before and after the diagnostic intervention was calculated. A minimal clinically important difference of 0.5 was considered clinically relevant for the food allergy quality of life questionnaire.

RESULTS

Seven of 1465 original identified publications were included in which the impact of an OFC on HRQL was investigated (total patients n = 1370). No other diagnostic interventions were investigated. Food allergy-specific parent-reported HRQL improved significantly after an OFC irrespective of the outcome in children with a suspected food allergy in two publications. The change was considered clinically relevant in one of two publications. In addition, parent-reported HRQL improved after an OFC to assess the eliciting dose in children with a confirmed food allergy. The parental burden was significantly reduced after an OFC to assess resolution of food allergy. A meta-analysis could not be performed due to the limited numbers of, and considerable heterogeneity between, eligible publications.

CONCLUSION

An OFC is associated with an improved food allergy-specific HRQL and a reduced parental burden of food allergy.

The potential of component-resolved diagnosis in laboratory diagnostics of allergy

The initial laboratory approach in the diagnosis of allergies is to detect the type of allergic reaction, i.e. whether the patient’s allergy is mediated by immunoglobulin E (IgE) or not. For this purpose, the concentration of total serum IgE (tIgE) and specific IgE (sIgE) are determined. Progress in laboratory diagnostics is the use of component-resolved diagnosis (CRD) which implies determination of sIgE against purified native and recombinant allergenic molecules. Component-resolved diagnosis is used in laboratory practice as singleplex and multiplex assays. The choice of allergen for singleplex assay is based on anamnesis, clinical findings of a patient and on skin prick test results. Multiplex-microarray assays simultaneously determine multiple sIgE’s against numerous allergens. The goal of CRD is to distinguish the true allergens from the cross-reactive allergen molecules. Component-resolved diagnosis allows predicting the risk of severe symptoms, as well as anticipating the development of allergies. Thus, determination of sIgE against allergenic components may significantly improve current diagnostics of allergy. Since this method is applied in laboratory practice just a few years, it is necessary to acquire new knowledge and experience, to establish good co-operation between specialist in medical biochemistry and laboratory medicine and the specialist allergologist, so that the method can be applied in a rational manner. Component-resolved diagnosis will significantly improve the diagnostics of IgE-mediated allergy in the future. The aim of this article is to present potentials of CRD in the laboratory diagnostics of allergy mediated by IgE.

Diagnosis of Food Allergy

Food allergy diagnosis remains challenging. Most standard methods are unable to differentiate sensitization from clinical allergy. Recognizing food allergy is of utmost importance to prevent life-threatening reactions. On the other hand, faulty interpretation of tests leads to overdiagnosis and unnecessary food avoidances. Highly predictive models have been established for major food allergens based on skin prick testing and food-specific immunoglobulin E but are lacking for most other foods. Although many newer diagnostic techniques are improving the accuracy of food allergy diagnostics, an oral food challenge remains the only definitive method of confirming a food allergy.

Sensitization profiles to peanut allergens across the United States

BACKGROUND

Measurement of IgE antibody to peanut components can aid in the prediction of allergic responses the food.

OBJECTIVE

To investigate the association between patient demographics (age, location) and allergic sensitization to peanut components across the United States.

METHODS

Serum samples from 12,155 individuals with peanut extract specific IgE levels of 0.35 kUA/L or higher were analyzed for IgE antibodies to Ara h 1, 2, 3, 8, and 9 by ImmunoCAP.

RESULTS

Among this population of peanut sensitized individuals, 79.1% of children (<3 years old) were sensitized to one or more peanut storage proteins (Ara h 1, 2, and/or 3), in contrast to 64.2% of adolescents (12-15 years old) and 22.1% of adults (>20 years old). Although sensitization was more prevalent to Ara h 2 than to the other storage proteins, a sizable fraction of patients were sensitized to Ara h 1 and/or 3 but not to Ara h 2 (eg, 13% of children <3 years old). Moreover, 9.6% of children, 10.2% of adolescents, and 10.5% of adults were sensitized to Ara h 9, whereas 2.4% of children, 49.4% of adolescents, and 42.9% of adults produced IgE to Ara h 8 (pathogenesis-related protein 10). Sensitization to Ara h 8 alone was markedly higher in the Northeastern United States relative to other regions of the country.

CONCLUSION

We conclude that sensitization to individual peanut components is highly dependent on age and geographic location. Given that a severe allergic reaction to peanut is unlikely in individuals with isolated sensitization to Ara h 8, a sizable fraction of patients, in particular adolescents and adults, may be at lower risk than anticipated based only on demonstration of sensitization to whole peanut extract.

Nitrogen balance after a single oral consumption of sacha inchi (Plukenetia volúbilis L.) protein compared to soy protein: a randomized study in humans

Sacha inchi is a seed produced in the Peruvian Amazonian and its oil is recognized by the lowering lipids effect in humans. The remaining material transformed to flour has a higher amount of protein, but, the nitrogen balance once ingested orally has not been studied. The present study was designed to evaluate the nitrogen balance after single consumption of 30 g of sacha inchi flour and compared with that obtained after consumption of 30 g soybean flour in adult men and women. This was a double-blind cohort study in 15 men and 15 women between 18 and 55 years old. Fifteen subjects received soy meal and 15 subjects received sacha inchi meal. Group receiving sacha inchi flour has comparable initial parameters as those receiving soybean flour (p > 0.05). Blood samples at different times were obtained. Urine for 24 h was collected to calculate nitrogen balance, p < 0.05 was considered significant. Plasma insulin levels increased post-prandial with a peak at 30 min. Thereafter, a reduction occurred. The magnitude of changes in insulin levels was similar in sacha inchi and soybean groups (p < 0.05). Lipid profile and inflammatory marker, C-reactive protein (CRP) and interleukin 6 (IL6) was not different at 0 or 24 h after sacha inchi or soy flour administration. The nitrogen balance was negative in the study but similar between both groups (p > 0.05). In conclusion, protein consumption of sacha inchi flour has the same nitrogen balance as soybean flour, shows acceptability for a single consumption and does not present serious adverse effects.

Deciphering the black box of food allergy mechanisms

OBJECTIVE

To review our current understanding of immunotherapy, the immune mechanisms underlying food allergy, and the methodological advances that are furthering our understanding of the role of immune cells and other molecules in mediating food allergies.

DATA SOURCES

Literature searches were performed using the following combination of terms: allergy, immunotherapy, food, and mechanisms. Data from randomized clinical studies using state-of-the-art mechanistic tools were prioritized.

STUDY SELECTIONS

Articles were selected based on their relevance to food allergy.

RESULTS

Current standard of care for food allergies is avoidance of allergenic foods and the use of epinephrine in case of severe reaction during unintentional ingestion. During the last few decades, great strides have been made in understanding the cellular and molecular mechanisms underlying food allergy, and this information is spearheading the development of exciting new treatments.

CONCLUSION

Immunotherapy protocols are effective in desensitizing individuals to specific allergens; however, recurrence of allergic sensitization is common after discontinuation of therapy. Interestingly, in a subset of individuals, immunotherapy is protective against allergens even after discontinuation of immunotherapy. Whether this protection is permanent is currently unknown because of inadequate long-term follow-up data. Research on understanding the underlying mechanisms may assist in modifying protocols to improve outcome and enable sustained unresponsiveness, rather than a temporary relief against food allergies. The cellular changes brought about by immunotherapy are still a black box, but major strides in our understanding are being made at an exciting pace.

Anti-Allergic Compounds from the Deep-Sea-Derived Actinomycete Nesterenkonia flava MCCC 1K00610

A novel cyclic ether, nesterenkoniane (1), was isolated from the deep-sea-derived actinomycete Nesterenkonia flava MCCC 1K00610, together with 12 known compounds, including two macrolides (2, 3), two diketopiperazines (4, 5), two nucleosides (6, 7), two indoles (8, 9), three phenolics (10–12), and one butanol derivate (13). Their structures were established mainly on detailed analysis of the NMR and MS spectroscopic data. All 13 compounds were tested for anti-allergic activities using immunoglobulin E (IgE) mediated rat mast RBL-2H3 cell model. Under the concentration of 20 μg/mL, 1 exhibited moderate anti-allergic activity with inhibition rate of 9.86%, compared to that of 37.41% of the positive control, loratadine. While cyclo(d)-Pro-(d)-Leu (4) and indol-3-carbaldehyde (8) showed the most potent effects with the IC₅₀ values of 69.95 and 57.12 μg/mL, respectively, which was comparable to that of loratadine (IC₅₀ = 35.01 μg/mL). To the best of our knowledge, it is the first report on secondary metabolites from the genus of Nesterenkonia.

Use of Food Allergy Panels by Pediatric Care Providers Compared With Allergists

BACKGROUND AND OBJECTIVE

Immunoglobullin E (IgE)-mediated food allergies affect 5% to 8% of children. Serum IgE levels assist in diagnosing food allergies but have low positive predictive value. This can lead to misinterpretation, overdiagnosis, and unnecessary dietary elimination. Use of IgE food allergen panels has been associated with increased cost and burden. The scale of use of these panels has not been reported in the medical literature.

METHODS

We conducted a retrospective review of a commercial laboratory database associated with a tertiary care pediatric academic medical center for food IgE tests ordered by all provider types during 2013.

RESULTS

A total of 10 794 single-food IgE tests and 3065 allergen panels were ordered. Allergists ordered the majority of single-food IgE tests (58.2%) whereas 78.8% of food allergen panels were ordered by primary care providers (PCPs) (P < .001). Of all IgE tests ordered by PCPs, 45.1% were panels compared with 1.2% of orders placed by allergists (P < .001). PCPs in practice for >15 years ordered a higher number of food allergen panels (P < .05) compared with PCPs with less experience. Compared with allergists, PCPs ordered more tests for unlikely causes of food allergies (P < .001). Total cost of IgE testing and cost per patient were higher for PCPs compared with allergists.

CONCLUSIONS

Review of food allergen IgE testing through a high volume outpatient laboratory revealed PCPs order significantly more food allergen panels, tests for uncommon causes of food allergy, and generate higher cost per patient compared with allergists. These results suggest a need for increased education of PCPs regarding proper use of food IgE tests.

Pearls and Pitfalls in Diagnosing IgE-Mediated Food Allergy

The term "food allergy" is used by many patients and clinicians to describe a range of symptoms that occur after ingestion of specific foods. However, not all symptoms occurring after food exposure are due to an allergic, or immunologic, response. It is important to properly evaluate and diagnose immunoglobulin E (IgE)-mediated food allergy as this results in reproducible, immediate onset, allergic reactions that can progress toward life-threatening anaphylaxis. Proper diagnosis requires understanding of the common foods that cause these reactions in addition to key historical elements such as symptoms, timing and duration of reaction, and risk factors that may predispose to development of IgE-mediated food allergy. Diagnostic testing for food-specific IgE can greatly aid the diagnosis. However, false-positive test results are very common and can lead to overinterpretation, misdiagnosis, and unnecessary dietary elimination. This review discusses important aspects to consider during evaluation of a patient for suspected IgE-mediated food allergy.

The rise of food allergy: Environmental factors and emerging treatments

Food allergy has rapidly increased in prevalence, suggesting an important role for environmental factors in disease susceptibility. The immune response of food allergy is characterized by IgE production, and new findings from mouse and human studies indicate an important role of the cytokine IL-9, which is derived from both T cells and mast cells, in disease manifestations. Emerging evidence suggests that route of exposure to food, particularly peanut, is important. Exposure through the skin promotes sensitization while early exposure through the gastrointestinal tract promotes tolerance. Evidence from mouse studies indicate a role of the microbiome in development of food allergy, which is supported by correlative human studies showing a dysbiosis in food allergy. There is no approved treatment for food allergy, but emerging therapies are focused on allergen immunotherapy to provide desensitization, while pre-clinical studies are focused on using adjuvants or novel delivery approaches to improve efficacy and safety of immunotherapy.

•

Emerging evidence suggests that route of exposure to food allergens in early life determines sensitization versus tolerance.

•

The microbiota and dietary factors appear to play a key role in susceptibility to food allergy.

•

Immunotherapy applied via different routes is currently the most promising form of experimental treatment for food allergy.