Comparison of open and double-blind placebo-controlled food challenges in diagnosis of food hypersensitivity amongst children

A comparison of double-blind, placebo-controlled food challenge and open food challenge

BACKGROUND

Double-blind, placebo-controlled food challenge (DBPCFC) remains the gold standard for diagnosing food allergy, despite sparse comparisons to open food challenges (OpenFCs). The objective of this retrospective study was to compare severity of symptoms and threshold values (cumulative dose of food allergen eliciting a clinical reaction) in children and adults with peanut allergy, challenged in an open and/or double-blind, placebo-controlled protocol.

METHODS

This study included patients from the Allergy Centre, Odense University Hospital with a positive oral food challenge, defined as strict objective signs, with peanut during the period 2001-2022. Severity of symptoms was graded using the Sampson's severity score. Distribution models of threshold values were calculated using log-normal interval-censored survival analysis, and the number of placebo reactions was evaluated.

RESULTS

In total, 318 positive OpenFCs and 86 DBPCFCs were included. There was no difference in severity of symptoms nor threshold values comparing the two challenge types, neither when stratified for age groups. However, a higher proportion of children experienced Grade 3 symptoms in the double-blind group. Only one patient had a positive reaction to a placebo challenge.

CONCLUSION

Our findings do not advocate for DBPCFC being superior to OpenFC, if the latter is performed with strict objective stop criteria by trained staff.

The Remaining Challenge to Diagnose and Manage Cow's Milk Allergy: An Opinion Paper to Daily Clinical Practice

Guidelines and recommendations for the diagnosis and management of cow's milk allergy (CMA) in childhood are based on scientific review of the available evidence. While this approach is the most rigorous, guidelines may not fully address all scenarios encountered by clinicians. Many symptoms of CMA overlap with other common childhood illnesses and are subjectively reported by the caregivers of the infant, as is the interpretation of the dietary interventions. Additionally, many healthcare professionals and caregivers do not follow the recommendations to perform an oral food challenge or reintroduction of cow's milk after a diagnostic elimination diet because (1) the infant is doing well and (2) the carer's fear of symptoms relapsing with this procedure. As a result, CMA in infants may be either under-diagnosed leading to reduced quality of life for families or over-diagnosed, resulting in unnecessary long-term elimination diets and increasing the risk for nutritional deficiencies. This paper discusses some of these controversial topics, focusing on misdiagnosis and mismanagement in clinical practice. The lack of objective diagnostic criteria can hamper the diagnosis and management of CMA in daily practice.

The role of diagnostic tests and oral food challenge results to predict sesame allergy

BACKGROUND

The presence of sesame allergy and its importance are increasing.

OBJECTIVE

To determine the results of sesame and tahini oral food challenges (OFCs) and whether sesame-specific immunoglobulin E and skin prick tests (SPTs) accurately predicted sesame allergy in children.

METHODS

Patients with suspected sesame allergy between June 1, 2018, and June 1, 2020, were examined.

RESULTS

Of 92 patients (n = 65, 70.7% of the patients were boys) with a median age of 2 years (interquartile range, 1.2-3.8 years), 64 were reactive to tahini. Of 64 patients, 41 had a positive OFC result and 23 had a consistent history. Of 54 sesame OFCs, 10 patients had a positive outcome. Of 44 with a negative outcome of sesame OFC, 4 experienced allergic reactions with tahini at home and 22 patients had a positive result for tahini OFC. In multivariate logistic regression analysis, clinical reactivity of sesame (either a consistent history or a positive OFC) was positively associated with sesame SPT (odds ratio, 2.120; 95% confidence interval, 1.136-3.957; P = .01) and tahini SPT (odds ratio, 1.661; 95% confidence interval, 1.143-2.413; P = .008). Nevertheless, sesame-specific immunoglobulin E did not predict clinical reactivity. Tahini OFC outcomes were well predicted for both sesame and tahini SPTs (area under the curves of 0.937 and 0.896, respectively, P < .001 for both). A sesame SPT wheal size of 5.25 mm had 90.6% sensitivity, 82.1% specificity, and 5.1 positive likelihood ratio. For tahini SPT, the 6-mm threshold had 100% sensitivity, 82.1% specificity, and 5.6 positive likelihood ratio.

CONCLUSION

In the OFC, tahini emerged as a more optimal diagnostic tool to avoid false negatives. Furthermore, both high sesame and tahini SPT levels individually can help predict the diagnosis of sesame allergy.

The dilemma of open or double-blind food challenges in diagnosing food allergy in children: Design of the ALDORADO trial

BACKGROUND

It is of major importance to diagnose food allergy accurately. Current guidelines support the use of oral food challenges to do so. The double-blind placebo-controlled food challenge (DBPCFC) has been regarded as the 'gold standard' for decades. However, DBPCFCs are costly, and time- and resource-intensive procedures. Structural implementation of less demanding open food challenges will only find support if research demonstrates that their outcome is comparable to DBPCFC, yet this has been proven difficult to investigate.

METHODS

We performed a literature review to investigate the diagnostic accuracy of oral food challenges and interviewed 19 parents of children with proven or suspected food allergy about the design of a trial to study this.

RESULTS

An overview of the dilemma of diagnosing food allergy using oral food challenges, and the methodological issues and parents' opinions to study this. No comparative studies have been performed using the latest guidelines on oral food challenges.

CONCLUSIONS

There is an urgent need to investigate the diagnostic accuracy of different oral food challenge protocols. We present the rationale and design of the ALDORADO trial (ALlergy Diagnosed by Open oR DOuble-blind food challenge) that has been set up to investigate whether the outcome of the open food challenge is comparable to DBPCFC.

Two Different Composite Markers Predict Severity and Threshold Dose in Peanut Allergy

BACKGROUND

Safe and cost-effective biological surrogate markers to evaluate the severity and threshold dose of peanut allergy (PA) reactions during an oral food challenge (OFC) are lacking.

OBJECTIVE

To evaluate biological markers associated with the severity and threshold dose of an allergic reaction during an OFC in a population of children with PA.

METHODS

Demographic and biological parameters of children with peanut OFC and basophil activation test (BAT) results were collected. Patients were stratified into 2 severity groups (mild-to-moderate and severe) and 2 cumulative threshold dose groups: low (LCTG) ≤100 mg crushed peanut and high >100 mg.

RESULTS

Among the 68 children included, there was a 96% concordance between the OFC and BAT result for the diagnosis of PA. Of the 56 children with a positive OFC and BAT to peanut (median age: 8.8 years), the severity of an allergic reaction and the cumulative threshold dose were not correlated (P = .24). Higher Ara h 2-specific IgE and FcεRI-positive control values were both associated with severe reactions to peanut. Combining these 2 markers led to a 92% sensitivity (84%-97%) and an 82% specificity (71%-89%) for severe reactions in all subjects. For children in the LCTG, a 4-variable composite marker, including age, normalized basophil sensitivity (EC₅₀), and FcεRI- and fMLP-positive control values, resulted in a 97% sensitivity (89%-99%) and 61% specificity (49%-71%).

CONCLUSION

Distinct composite markers including BAT allergen-specific and non-allergen-specific parameters appear to be associated with severity and cumulative threshold dose in children with PA.

Change in exhaled nitric oxide during peanut challenge is related to severity of reaction

BACKGROUND

Peanut allergy affects 3% of Australian children and has a higher risk of anaphylaxis than most food allergies. Predicting who is likely to develop anaphylaxis is still an inexact science. The fraction of exhaled nitric oxide (FeNO) shows promise as a biomarker involved in peanut allergy, as nitric oxide plays a role in inhibiting mast cell degranulation which is relevant in anaphylaxis, where mast cell degranulation plays a mediator role. The aim of this study was to assess the change in FeNO in children during peanut challenge.

METHODS

Thirty-six children aged from 5 to 17 years were recruited for open-labelled peanut challenge. Participants had skin prick test to peanut performed, and serum collected for Ara h2 specific IgE and peanut specific IgE. FeNO was measured by portable device (NIOX VERO) prior to and throughout the peanut challenge.

RESULTS

When grouped according to reaction type at peanut challenge (anaphylaxis, clinical allergy not anaphylaxis and tolerant), there were significant differences in the mean change in FeNO measurement between the anaphylaxis group and the clinical allergy, not anaphylaxis group (p = 0.005), and between the anaphylaxis group and tolerant group (p < 0.0001).

CONCLUSIONS

FeNO decreased more significantly in those who subsequently developed anaphylaxis than in those with clinical allergy, not anaphylaxis or negative peanut challenge (tolerance). As a bedside test that can be used in children, it has potential for further research into mechanisms of anaphylaxis in food allergy and potentially assists in predicting an imminent anaphylactic reaction in some patients.Trial registration ClinicalTrials.gov: PEAnut Anaphylaxis Predictors (PEAAP) NCT02424136.

Diagnosis of Sesame Allergy: Analysis of Current Practice and Exploration of Sesame Component Ses i 1

BACKGROUND

Sesame is an allergen of increasing importance.

OBJECTIVE

We sought to characterize the outcomes of oral food challenges (OFCs) to sesame and evaluate the diagnostic accuracy of skin prick testing (SPT), sesame, and Ses i 1-specific IgE (sIgE).

METHODS

We reviewed sesame OFCs performed at the Mount Sinai pediatric allergy clinic between January 2010 and April 2018. We assessed the accuracy of diagnostic tests by calculating the area under the curve (AUC) of the receiver operating characteristic curves. The association between OFC outcome and sesame sensitization was analyzed using a logistic regression, which was then used to estimate the 95% positive predictive value (PPV) of these tests.

RESULTS

We identified 341 patients (69% male, mean age 7.7 years) who underwent sesame OFC. Among 106 (31%) positive OFCs, the median cumulative eliciting dose was 500 mg sesame protein (1/2 teaspoon tahini). Sesame SPT wheal ≥6 mm had sensitivity 54.1% and specificity 87.8%; AUC 0.756 (95% confidence interval [CI], 0.699-0.814). SPT wheal size ≥14 mm had 95% PPV. Sesame-sIgE level did not correlate with OFC outcome. Ses i-sIgE levels were analyzed in 30 patients using the Immuno Solid-phase Allergen Chip (ISAC) microarray and were significantly associated with OFC outcome (AUC: 0.715 [95% CI, 0.541-0.890]). Ses i 1-sIgE ≥0.3 ISAC Standardized Units had sensitivity 58.3% and specificity 83.3%.

CONCLUSIONS

This is the largest study of sesame allergy to date. Sesame SPT is a more accurate predictor of sesame allergy compared with sesame sIgE. Ses i 1-sIgE appears promising but requires further study regarding diagnostic accuracy.

Eliciting dose is associated with tolerance development in peanut and cow's milk allergic children

Background

Tolerance development rates differ between food allergies. Almost all previous studies have not used the gold standard method, the double-blind, placebo-controlled food challenge (DBPCFC), which may affect the reported prevalence rates. Little is known about the association of the eliciting dose (ED) obtained during the initial DBPCFC with later tolerance development.

Methods

This was a retrospective, tertiary care study of children who had a positive DBPCFC to either peanut, milk or egg, and at least one follow-up food challenge (open or DBPCFC) with the same food. The association between ED and negative (tolerant) follow-up food challenge outcome was analyzed by logistic regression, with adjustment for confounders. Suspected confounders were initial DBPCFC test characteristics, atopic comorbidities and serum specific IgE (sIgE) levels.

Results

In 47 peanut allergic children, tolerance developed in 27.7% (median follow-up duration of 43 months). In 80 milk (follow-up 23 months) and 55 egg (follow-up 37 months) allergic children, tolerance developed in 55.0% and 65.5%. The ED obtained during the initial DBPCFC was significantly associated with tolerance development in peanut and milk allergy, but not in egg allergy.

Conclusion

Approximately 1 out of 4 children with DBPCFC confirmed peanut allergy developed tolerance, compared to more than half of the children with milk or egg allergy, respectively. Tolerance development in peanut and milk allergy is significantly associated with ED at initial DBPCFC.

An update to the Milk Allergy in Primary Care guideline

The Milk Allergy in Primary (MAP) Care guideline was first published in 2013 in this journal. MAP aimed to provide simple and accessible algorithms for UK clinicians in primary care, detailing all the steps between initial presentation, through diagnosis, management and tolerance development. Despite its UK focus, it soon became clear that MAP was being accessed internationally and thus an updated International Milk Allergy in Primary Care (iMAP) guideline was published in 2017. Both guidelines used existing international consensus guidelines to develop accessible algorithms accompanied by patient information leaflets. In 2018, the guidelines were criticised for 3 distinct reasons: promoting the overdiagnosis of cow's milk allergy (CMA), negatively impacting breastfeeding and the possibility of industry influence on the guidelines. The authors address these criticisms using available evidence and, in the context of this and in consultation with patient groups, members of the General Practice Infant Feeding Network and other infant feeding healthcare leads, have collaboratively produced updated algorithms and an information leaflet to support breastfeeding. We believe iMAP is now closer to its original aim of facilitating early and accurate diagnosis of CMA, whilst minimising, as far as possible, any concerns around overdiagnosis or a risk to breastfeeding rates. We continue to welcome open and constructive engagement about how best to achieve these aims to provide evidence-based, practical guidelines for the primary care practitioner.

A Phase 2 Randomized Controlled Multisite Study Using Omalizumab-facilitated Rapid Desensitization to Test Continued vs Discontinued Dosing in Multifood Allergic Individuals

BACKGROUND

As there is limited data on the sustainability of desensitization of multifood-oral immunotherapy (multifood-OIT), we conducted a multisite multifood-OIT study to compare the efficacy of successful desensitization with sustained dosing vs discontinued dosing after multifood-OIT.

METHODS

We enrolled 70 participants, aged 5-22 years with multiple food allergies confirmed by double-blind placebo-controlled food challenges (DBPCFCs). In the open-label phase of the study, all participants received omalizumab (weeks 1-16) and multi-OIT (2-5 allergens; weeks 8-30) and eligible participants (on maintenance dose of each allergen by weeks 28-29) were randomized 1:1:1 to 1 g, 300 mg, or 0 mg arms (blinded, weeks 30-36) and then tested by food challenge at week 36. Success was defined as passing 2 g food challenge to at least 2 foods in week 36.

FINDINGS

Most participants were able to reach a dose of 2 g or higher of each of 2, 3, 4, and 5 food allergens (as applicable to the participant's food allergens in OIT) in week 36 food challenges. Using an intent-to-treat analysis, we did not find evidence that a 300 mg dose was effectively different than a 1 g dose in maintaining desensitization, and both together were more effective than OIT discontinuation (0 mg dose) (85% vs 55%, P = 0.03). Fifty-five percent of the intent-to-treat participants and 69% of per protocol participants randomized to the 0 mg arm showed no objective reactivity after 6 weeks of discontinuation. Cross-desensitization was found between cashew/pistachio and walnut/pecan when only one of the foods was part of OIT. No statistically significant safety differences were found between the three arms.

INTERPRETATION

These results suggest that sustained desensitization after omalizumab-facilitated multi-OIT best occurs through continued maintenance OIT dosing of either 300 mg or 1 g of each food allergen as opposed to discontinuation of multi-OIT.

FUNDING

Sean N. Parker Center for Allergy and Asthma Research at Stanford University, Jeff and MacKenzie Bezos, NIAID AADCRC U19AI104209.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov number, NCT02626611.

Gastrointestinal Symptoms of Food Challenge-proven Non-IgE Cow's Milk Allergy Are Dissipated by Early School Age

OBJECTIVES

The aim of this study was to evaluate the current well-being and dietary restrictions in children 6 years after food challenge-confirmed diagnosis of non-IgE cow's milk protein allergy, compared to peers with gastrointestinal symptoms but negative food challenge. This study aimed to evaluate the diagnostic process retrospectively.

METHODS

This is an Internet-based survey for mothers whose children underwent 6 years ago the double-blind, placebo-controlled food challenge for cow's milk (CM) because of gastrointestinal symptoms causing suspicion of non-IgE CM protein allergy. Concurrent dietary restrictions, overall well-being, medical history, and retrospective views on the food challenge were queried using a study-specific questionnaire, the Quality of life using PedsQL general score and parental stress with the Parenting Stress Index questionnaire.

RESULT

Mothers of 42 children (23 girls), median age of 6.7 years (range 5.7-8.6), participated in the survey, the response rate was 70%. All children now consumed cow's milk protein. The only food restrictions reported were empirical lactose-free diets in 7 children (17%). One-third of the children in both groups were presently reported to have eating-related issues such as picky eating. Quality of life was good and present parenting stress was average in both groups. The majority of the mothers (87%) felt positive or neutral about the food challenge performed in infancy.

CONCLUSIONS

The non-IgE CM allergy with gastrointestinal symptoms diagnosed in infancy was a transient condition with good outcome. At an early school age, nearly all children have a good quality of life and a regular diet. The use of the double-blind, placebo-controlled food challenge was well-endorsed.

Physician's appraisal vs documented signs and symptoms in the interpretation of food challenge tests: The EuroPrevall birth cohort

BACKGROUND

Blinded food challenges are considered the current gold standard for the diagnosis of food allergies. We used data from a pan-European multicenter project to assess differences between study centers, aiming to identify the impact of subjective aspects for the interpretation of oral food challenges.

METHODS

Nine study centers of the EuroPrevall birth cohort study about food allergy recruited 12 049 newborns and followed them for up to 30 months in regular intervals. Intensive training was conducted and every center visited to ensure similar handling of the protocols. Suspected food allergy was clinically evaluated by double-blind, placebo-controlled food challenges using a nine dose escalation protocol. The primary challenge outcomes based on physician's appraisal were compared to documented signs and symptoms.

RESULTS

Of 839 challenges conducted, study centers confirmed food allergy in 15.6% to 53.6% of locally conducted challenges. Centers reported 0 to 16 positive placebo challenges. Worsening of eczema was the most common sign when challenged with placebo. Agreement between documented objective signs and the challenge outcome assigned by the physician was heterogeneous, with Cohen's kappa spanning from 0.42 to 0.84.

CONCLUSIONS

These differences suggest that the comparison of food challenge outcomes between centers is difficult despite common protocols and training. We recommend detailed symptom assessment and documentation as well as objective sign-based challenge outcome algorithms to assure accuracy and comparability of blinded food challenges. Training and supervision of staff conducting food challenges is a mandatory component of reliable outcome data.

Food Challenge and Community-Reported Reaction Profiles in Food-Allergic Children Aged 1 and 4 Years: A Population-Based Study

BACKGROUND

Oral food challenge is the main tool for diagnosing food allergy, but there is little data on the reaction profiles of young children undergoing challenges, nor how these reactions compare to reactions on accidental ingestion in the community.

OBJECTIVES

To compare reaction profiles from food challenges and parent-reported reactions on accidental ingestion, and assess predictors of severe reactions.

METHODS

HealthNuts is a longitudinal population-based cohort study of 5276 1-year-old infants. Infants underwent skin prick tests and those with identifiable wheals were offered food challenges. Food challenges were repeated at age 4 years in those with previous food allergy or reporting new food allergies. Community-reported reactions were ascertained from parent questionnaires.

RESULTS

Food challenges were undertaken in 916 children at age 1 year and 357 children at age 4 years (a total of 2047 peanut, egg, or sesame challenges). Urticaria was the most common sign in positive challenges at both ages (age 1 year, 88.7%, and age 4 years, 71.2%) although angioedema was significantly more common at age 4 years (40.1%) than at age 1 year (12.9%). Anaphylaxis was equally uncommon at both ages (2.1% and 2.8% of positive challenges at ages 1 and 4 years, respectively) but more common for peanut than for egg (4.5% and 1.2% of positive challenges at ages 1 and 4 years, respectively). The patterns of presenting signs reported during community reactions were similar to those observed in formal food challenges. Serum food-specific IgE levels of 15 kU/L or more were associated with moderate to severe reactions but skin prick test was not.

CONCLUSIONS

There was a shift from the most common presenting reaction of urticaria during food challenges toward more angioedema in older children. Serum food-specific IgE levels were associated with reaction severity.

Early oral immunotherapy in peanut-allergic preschool children is safe and highly effective

BACKGROUND

Oral immunotherapy (OIT) is an effective experimental food allergy treatment that is limited by treatment withdrawal and the frequent reversibility of desensitization if interrupted. Newly diagnosed preschool children may have clinical and immunological characteristics more amenable to treatment.

OBJECTIVE

We sought to test the safety, effectiveness, and feasibility of early OIT (E-OIT) in the treatment of peanut allergy.

METHODS

We enrolled 40 children aged 9 to 36 months with suspected or known peanut allergy. Qualifying subjects reacted to peanut during an entry food challenge and were block-randomized 1:1 to receive E-OIT at goal maintenance doses of 300 or 3000 mg/d in a double-blinded fashion. The primary end point, sustained unresponsiveness at 4 weeks after stopping early intervention oral immunotherapy (4-SU), was assessed by double-blinded, placebo-controlled food challenge either upon achieving 4 prespecified criteria, or after 3 maintenance years. Peanut-specific immune responses were serially analyzed. Outcomes were compared with 154 matched standard-care controls.

RESULTS

Of 40 consented subjects, 3 (7.5%) did not qualify. Overall, 29 of 37 (78%) in the intent-to-treat analysis achieved 4-SU (300-mg arm, 17 of 20 [85%]; 3000 mg, 12 of 17 [71%], P = .43) over a median of 29 months. Per-protocol, the overall proportion achieving 4-SU was 29 of 32 (91%). Peanut-specific IgE levels significantly declined in E-OIT-treated children, who were 19 times more likely to successfully consume dietary peanut than matched standard-care controls, in whom peanut-specific IgE levels significantly increased (relative risk, 19.42; 95% CI, 8.7-43.7; P < .001). Allergic side effects during E-OIT were common but all were mild to moderate.

CONCLUSIONS

At both doses tested, E-OIT had an acceptable safety profile and was highly successful in rapidly suppressing allergic immune responses and achieving safe dietary reintroduction.

Late reactions in food-allergic children and adolescents after double-blind, placebo-controlled food challenges

The time during which children are observed following a double-blind, placebo-controlled food challenge (DBPCFC) varies in clinical practice. There are little data on late reactions (LRs) following DBPCFCs. Therefore, we determined the prevalence, severity and clinical characteristics of late reactions in food-allergic children and adolescents after DBPCFC, and ascertained which factors are associated with, and may predict, LRs. Logistic regression analyses were performed to investigate which factors were associated with LRs and to develop the association and prediction models. A total of 1142 children underwent DBPCFCs (child-test combinations). Of these 1142 child-test combinations, 400 reported LRs following the DBPCFC. LRs in food-allergic children after DBPCFC are poorly predictable and are generally not severe. All LRs, including those on the placebo day, are more frequently reported in younger children. Children who do not experience severe immediate reactions may be safely discharged home 2 h after a DBPCFC.

Wheat allergy: diagnosis and management

Triticum aestivum (bread wheat) is the most widely grown crop worldwide. In genetically predisposed individuals, wheat can cause specific immune responses. A food allergy to wheat is characterized by T helper type 2 activation which can result in immunoglobulin E (IgE) and non-IgE mediated reactions. IgE mediated reactions are immediate, are characterized by the presence of wheat-specific IgE antibodies, and can be life-threatening. Non-IgE mediated reactions are characterized by chronic eosinophilic and lymphocytic infiltration of the gastrointestinal tract. IgE mediated responses to wheat can be related to wheat ingestion (food allergy) or wheat inhalation (respiratory allergy). A food allergy to wheat is more common in children and can be associated with a severe reaction such as anaphylaxis and wheat-dependent, exercise-induced anaphylaxis. An inhalation induced IgE mediated wheat allergy can cause baker’s asthma or rhinitis, which are common occupational diseases in workers who have significant repetitive exposure to wheat flour, such as bakers. Non-IgE mediated food allergy reactions to wheat are mainly eosinophilic esophagitis (EoE) or eosinophilic gastritis (EG), which are both characterized by chronic eosinophilic inflammation. EG is a systemic disease, and is associated with severe inflammation that requires oral steroids to resolve. EoE is a less severe disease, which can lead to complications in feeding intolerance and fibrosis. In both EoE and EG, wheat allergy diagnosis is based on both an elimination diet preceded by a tissue biopsy obtained by esophagogastroduodenoscopy in order to show the effectiveness of the diet. Diagnosis of IgE mediated wheat allergy is based on the medical history, the detection of specific IgE to wheat, and oral food challenges. Currently, the main treatment of a wheat allergy is based on avoidance of wheat altogether. However, in the near future immunotherapy may represent a valid way to treat IgE mediated reactions to wheat.

Ethnic differences in peanut allergy patterns in South African children with atopic dermatitis

BACKGROUND

The prevalence of peanut allergy in South Africa is unknown, but previously thought to be low, particularly in black South Africans. This study aimed to determine the prevalence of component patterns and predictive values of screening tests in peanut allergy in South African children with atopic dermatitis (AD).

METHODOLOGY

This was a prospective, observational study in a pediatric university hospital in Cape Town. Children with AD, aged 6 months to 10 years, were recruited randomly. They were assessed for sensitization and allergy to peanut by questionnaire, skin prick tests (SPT), Immuno Solid Phase Allergen Chip test, ImmunoCAP component tests to Ara h 1, 2, 3, 8, and 9, and incremental food challenges.

RESULTS

A total of 100 participants (59 black Africans and 41 of mixed race) were enrolled, median age 42 months. There was a high and comparable rate of peanut sensitization in both black African (41%) and mixed race patients (50%), but a significantly lower prevalence of peanut allergy in the black African group (15% vs. 38%, p = 0.01). The component Ara h 2 was the most useful in differentiating allergy from tolerance in both ethnic groups, but had a significantly lower predictive value for peanut allergy in blacks (53%) vs. mixed race (93%). Overall, SPT and Ara h 2 produced the highest area under the receiver operating characteristic curve. A total of 95% positive predictive values (PPV) for SPT, peanut-specific IgE, and Ara h 2 levels varied significantly between the two ethnic groups.

CONCLUSION

The prevalence of peanut allergy is high in South African children with AD, but significantly lower in blacks compared to mixed race patients. The component Ara h 2 is useful for differentiating allergy from tolerance in both ethnic groups. Ninety-five% PPV for peanut allergy tests may need to be revised by ethnic group.

Tolerance to egg proteins in egg-sensitized infants without previous consumption

BACKGROUND

Egg-sensitized infants who have never eaten egg may react at first ingestion. We sought to determine the association between skin prick test (SPT) and specific IgE (sIgE) to egg proteins (EP) and oral food challenge (OFC) outcomes to find cut-off points which can diagnose egg allergy.

METHODS

One hundred and fifty-four infants up to 18 months, with cow's milk allergy (CMA) and/or atopic dermatitis (AD) without previous egg consumption, were recruited. SPT to EP were performed. If it was positive, sIgE was performed. If positive SPT and/or sIgE (n = 94), OFC was performed between 12 and 18 months. Receiver operating characteristic (ROC) curves were plotted, and the outcome of the OFC was related to SPT and sIgE. The cut-off points with the best diagnostic accuracy were found.

RESULTS

Ninety-four patients were sensitized to egg (69%) and 60 nonsensitized (31%). Of the sensitized, 27 tolerated cooked (CE) and raw egg (RE) (28.7%). Sixty-seven were allergic (71.3%): 29 reacted to CE, seven to egg yolk (EY) and 22 to egg white (EW) and 38 reacted to RE. 69.2% tolerated CE. EW SPT and ovalbumin (OVA) sIgE have the best area under the curve (AUC). The higher positive predictive values (PPV) were obtained for EW SPT and EW sIgE.

CONCLUSIONS

In egg-sensitized infants with EW SPT ≥8 mm and/or EW sIgE ≥8.36 KU/l, egg diagnostic OFC can be avoided as there is 94% probability of becoming positive. In the other patients, OFC should be performed safely and early to avoid unnecessary diets.

Oral food challenge and food allergy quality of life in caregivers of children with food allergy

BACKGROUND

Food allergy is associated with diminished patient and caregiver quality of life (QoL). Although oral food challenge (OFC) improves QoL of individuals with food allergy, its effects on caregiver QoL are unknown.

OBJECTIVES

To determine if differences in caregiver QoL exist based on their child undergoing OFC.

METHODS

Caregivers of individuals with food allergy who underwent OFCs between 2001 and 2012 at the University of Michigan Food Allergy Center completed the Food Allergy Quality of Life-Parental Burden index and a questionnaire that assessed details of the most-severe reaction by an individual with food allergy. Results were compared with 305 caregivers of individuals with food allergy who were unchallenged. All questionnaire data regarding the characteristics of the reactions of individuals with food allergy were verified through chart review.

RESULTS

A total of 115 caregivers of individuals with food allergy who were undergoing OFC completed the QoL assessment. Caregivers of individuals with food allergy who were undergoing OFC had a significantly lower (better) QoL score than controls who were not challenged (1.5 vs 1.88; P = .02). Furthermore, within the challenged cohort, there was no significant difference in QoL score between those with a passing OFC (eg, non-reactive) and a failing OFC (eg, reactive) (1.42 vs 1.34; P = .83). In an adjusted linear regression model, the QoL score was significantly better among caregivers of individuals with food allergy who were undergoing OFC and with an income >$50,000 but significantly worsened for caregivers with multiple individuals with food allergy or if the individual with food allergy had atopic dermatitis.

CONCLUSION

The caregiver QoL score is better with individuals with food allergy who underwent OFC versus controls who were unchallenged but not significantly different based on OFC outcome. QoL is, in addition, moderated by income, the presence of atopic dermatitis, and having multiple individuals with food allergy. OFC is associated with better caregiver QoL, irrespective of challenge outcome.

The natural history of cow's milk allergy in north-eastern Poland

PURPOSE

The rate of cow's milk allergy diminishes with age. There is not enough information concerning geographical trends in persistent cow's milk allergy in children. The objective of the study was to evaluate the prevalence of persistent cow's milk allergy in children previously diagnosed with IgE-mediated cow's milk allergy (CMA).

MATERIAL/METHODS

Diagnosis of cow's milk allergy was established by a medical history of symptoms associated with exposure to cow's milk, positive skin prick tests with cow's milk, the presence of milk-specific IgE, and by a positive double- or single-blind placebo-controlled food challenge with milk confirmed by a positive open-controlled milk challenge. A second oral challenge was performed after at least one year of a milk-free diet and children with a positive oral milk rechallenge were diagnosed as having a persistent CMA.

RESULTS

Two hundred ninety-one children, 2-14 years of age (mean 5.30±3.16 years, 95% CI, 5.02-5.62 years) completed the study. Persistent CMA was diagnosed in 79 patients (27.1%). Two hundred twelve children (72.9%) outgrew their allergy to cow's milk at a mean age of 5 years after an average time of 16.4±0.8 months on an elimination diet. Eighty percent of children below 3 years of age became milk tolerant. Milk-specific IgE (p=0.018) and history of paternal bronchial asthma and/or rhinitis (p=0.020) were associated with persistence of cow's milk allergy in regression analysis.

CONCLUSIONS

An age above 3 years, as well as features of atopy, individual and familial, may be associated with a risk of delayed tolerance to milk in children.

Characterization of plasma cytokines in an infant population cohort of challenge-proven food allergy

BACKGROUND

Sensitization to food allergens indicates the production of food-specific IgE; however, sensitization is not a definite indicator of allergic reaction upon ingestion (N Engl J Med, 344, 2001, 30: J Allergy Clin Immunol, 120, 2007, 491). Currently, food challenge is the best approach to identify the presence or absence of allergy. While 95% positive predictive values (PPVs) thresholds for sIgE can assist with identifying increased likelihood of allergy among those who are sensitized, there are no specific biological markers that differentiate between allergic and sensitized individuals.

OBJECTIVES

To determine whether plasma serum cytokine profiles predict (i) sensitization to peanut and egg and (ii) food allergy among sensitized infants.

METHODS

Peanut-sensitized (PT) and egg-sensitized 14-month-old infants and nonsensitized controls enrolled in HealthNuts, a population-based study of food allergy, underwent an oral food challenge (OFC). Blood was collected within 1 h after OFC. Serum levels of Th1, Th2 and regulatory cytokines were determined in allergic (n = 79), sensitized (n = 40) and nonsensitized, nonallergic (n = 37) infants by multiplex assay.

RESULTS

Food-sensitized infants had significantly higher plasma IL-4, IL-13, IL-12p70 and lower IL-10 levels compared to nonsensitized infants. IL-10 and IL-6 levels were significantly higher in sensitized compared with allergic infants. Egg-allergic infants had significantly higher IL-13 and IL-12p70 levels compared to peanut-allergic (PA) infants.

CONCLUSION

Levels of Th2-related cytokines in plasma are higher in food-sensitized infants, irrespective of clinical food allergy status. In contrast, IL-10 levels appear to predict food allergy among sensitized infants. Differences in IL-13 and IL-12p70 between egg- and peanut-allergic infants could help explain the different resolution rates of the allergies.

Skin prick test responses and allergen-specific IgE levels as predictors of peanut, egg, and sesame allergy in infants

BACKGROUND

Ninety-five percent positive predictive values (PPVs) provide an invaluable tool for clinicians to avoid unnecessary oral food challenges. However, 95% PPVs specific to infants, the age group most likely to present for diagnosis of food allergy, are limited.

OBJECTIVE

We sought to develop skin prick test (SPT) and allergen-specific IgE (sIgE) thresholds with 95% PPVs for challenge-confirmed food allergy in a large population-based cohort of 1-year-old infants with challenges undertaken irrespective of SPT wheal size or previous history of ingestion.

METHODS

HealthNuts is a population-based, longitudinal food allergy study with baseline recruitment of 1-year-old infants. Infants were recruited from council-run immunization sessions during which they underwent SPTs to 4 allergens: egg, peanut, sesame, and cow's milk/shrimp. Any infant with a detectable SPT response was invited to undergo oral food challenge and sIgE testing.

RESULTS

Five thousand two hundred seventy-six infants participated in the study. Peanut SPT responses of 8 mm or greater (95% CI, 7-9 mm), egg SPT responses of 4 mm or greater (95% CI, 3-5 mm), and sesame SPT responses of 8 mm or greater (95% CI, 5-9 mm) had 95% PPVs for challenge-proved food allergy. Peanut sIgE levels of 34 kUA/L or greater (95% CI, 14-48 kUA/L) and egg sIgE levels of 1.7 kUA/L or greater (95% CI, 1-3 kUA/L) had 95% PPVs for challenge-proved food allergy. Results were robust when stratified on established risk factors for food allergy. Egg SPT responses and sIgE levels were poor predictors of allergy to egg in baked goods.

CONCLUSION

These 95% PPVs, which were generated from a unique dataset, are valuable for the diagnosis of food allergy in young infants and were robust when stratified across a number of different risk factors.

New validated recipes for double-blind placebo-controlled low-dose food challenges

Double-blind placebo-controlled food challenges are considered the most reliable method to diagnose or rule out food allergy. Despite this, there are few validated challenge recipes available. The present study aimed to validate new recipes for low-dose double-blind placebo-controlled food challenges in school children, by investigating whether there were any sensory differences between the active materials containing cow's milk, hen's egg, soy, wheat or cod, and the placebo materials. The challenge materials contained the same hypoallergenic amino acid-based product, with or without added food allergens. The test panels consisted of 275 school children, aged 8-10 and 14-15 yr, respectively, from five Swedish schools. Each participant tested at least one recipe. Standardized blinded triangle tests were performed to investigate whether any sensory differences could be detected between the active and placebo materials. In our final recipes, no significant differences could be detected between the active and placebo materials for any challenge food (p > 0.05). These results remained after stratification for age and gender. The taste of challenge materials was acceptable, and no unfavourable side effects related to test materials were observed. In summary, these new validated recipes for low-dose double-blinded food challenges contain common allergenic foods in childhood; cow's milk, hen's egg, soy, wheat and cod. All test materials contain the same liquid vehicle, which facilitates preparation and dosing. Our validated recipes increase the range of available recipes, and as they are easily prepared and dosed, they may facilitate the use of double-blind placebo-controlled food challenges in daily clinical practice.

Asthmatic response to milk ingestion challenge in adults: a comparison of the open and double-blind challenges

BACKGROUND

Cow's milk allergy can participate in pathophysiological mechanisms underlying bronchial asthma in some adult patients. This role should ultimately be confirmed by means of a milk ingestion challenge. In this study, the diagnostic value of the open food ingestion challenge (OFICH) and the double-blind placebo-controlled food challenge (DBPCFC) techniques with milk were compared in adult patients suffering from bronchial asthma with suspected milk allergy.

METHODS

In 87 asthmatics with a suspected history and positive skin tests for milk, the 87 OFICHs and DBPCFCs were performed in combination with spirometry and followed up to 72 h after the challenge.

RESULTS

Of 87 patients, 74 (85%) developed a positive asthmatic response (AR) (20 immediate, 33 late, 6 dual late and 15 delayed; p < 0.01) and 13 (15%) developed a negative AR (p > 0.1) to OFICH. Seventy-five (86%) developed a positive AR (17 immediate, 35 late, 8 dual late and 15 delayed; p < 0.01) and 12 (14%) developed a negative AR (p > 0.05) to DBPCFC. The correlation between the OFICH and DBPCFC was statistically significant (p < 0.01). All placebo control challenges were negative (p > 0.2).

CONCLUSIONS

In some adults with bronchial asthma, involvement of an allergy to cow's milk results in the appearance of various AR types (immediate, late, dual late or delayed). The milk allergy can be confirmed by open or double-blind techniques, combined with spirometry. No significant differences were found between the OFICH and DBPCFC results. OFICH with natural milk combined with spirometry seems, therefore, to be an adequate technique for the detection of milk allergy in asthmatics. The DBPCFC can be performed as an additional check, if necessary.

The optimal diagnostic workup for children with suspected food allergy

Food allergy is defined as an abnormal immunologic reaction to food proteins that causes an adverse clinical reaction. In addition to well-known acute allergic reactions and anaphylaxis triggered by immunoglobulin E antibody-mediated immune responses to food proteins, there is an increasing recognition of cell-mediated disorders such as eosinophilic esophagitis and food protein-induced enterocolitis syndrome. More than 90% of food allergies in childhood are caused by eight foods: cow's milk, hen's egg, soy, peanuts, tree nuts, wheat, fish, and shellfish. The diagnostic workup for a child with suspected food allergy includes a detailed medical history, physical examination, food allergy screening tests, and responses to an elimination diet and an oral food challenge. None of the screening tests, alone or in combination, can definitely diagnose or exclude a food allergy. Novel diagnostic methods including those that focus on immune responses to specific food proteins or epitopes of specific proteins are under active study. Unconventional diagnostic methods are increasingly used, but they lack scientific rationale, standardization, and reproducibility. In selected cases, such as eosinophilic esophageal gastroenteropathies or food protein-induced gastroesophageal reflux disease, invasive procedures are mandatory for an accurate diagnosis. Properly done, an oral food challenge is still the gold standard in the diagnostic workup. An incorrect diagnosis is likely to result in unnecessary dietary restrictions, which, if prolonged, may adversely affect the child's nutritional status and growth.

Diagnosis and management of cow's milk protein allergy in infants

BACKGROUND

Cow's milk protein allergy (CMPA) is frequently suspected in infants with a variety of symptoms. A thorough history and careful clinical examination are necessary to exclude other underlying diseases and to evaluate the severity of the suspected allergy. Care should be taken to diagnose CMPA adequately to avoid an unnecessary diet.

DATA SOURCES

We make recommendations based on systematic literature searches using the best-available evidence from PubMed, Cumulative Index to Nursing and Allied Health Literature, and bibliographies.

RESULTS

Skin prick tests, patch tests and serum specific IgE are only indicative of CMPA. Breastfed infants have a decreased risk of developing CMPA; an elimination diet for the mother is indicated if CMPA is confirmed. If a food challenge is positive in formula fed infants, an extensively hydrolysed formula and cow's milk-free diet is recommended. If symptoms do not improve, an amino acid based formula should be considered. In severe CMPA with life-threatening symptoms, an amino-acid formula is recommended.

CONCLUSIONS

Elimination diet by a double-blind placebo controlled food challenge is the gold standard for diagnosis. Elimination of the offending allergen from the infants' diet is the main treatment principle.

Open oral food challenge in the confirmation of cow's milk allergy mediated by immunoglobulin E

BACKGROUND

The most reliable method to diagnose food allergy or to determine tolerance is the oral food challenge.

OBJECTIVES

The aim of this study was to describe the open oral food challenge applied to children with suspicion of cow's milk allergy mediated by immunoglobulin E, and evaluate the relation between the clinical history and skin prick test with the challenge outcomes.

PATIENTS AND METHODS

Forty-six children (median age 13.8 months), with clinical history of immediate reactions to cow's milk and positive skin prick test, underwent an open oral food challenge with cow's milk.

RESULTS

The challenge was positive in 41.3%. Cutaneous reactions were the most common (73.7%), followed by respiratory (57.9%) and gastrointestinal reactions (36.8%). According to the severity of the reactions, 57.9%, 36.8% and 5.3% had mild, moderate and severe reactions, respectively. Oral antihistamine was sufficient as treatment in all positive cases. A higher frequency of positive skin prick test with total milk and casein was observed in children with positive oral food challenge. There was a significant agreement between the reactions reported by the family history and those observed during the challenge for 68.4% of children with positive results (Kappa = 0.728; p < 0.001).

CONCLUSIONS

The method was considered suitable for children up to three years of age, and is safe and easy to perform. There was a significant correlation between the clinical history and the challenge outcomes. A positive skin prick test with total milk and casein was significantly associated with positive challenge results.

Late type of bronchial response to milk ingestion challenge: a comparison of open and double-blind challenge

Background. In some asthmatics the food allergy, for example, to milk, can participate in their bronchial complaints. The role of food allergy should be confirmed definitively by food ingestion challenge performed by an open challenge with natural foods (OFICH) or by a double-blind placebo-controlled food challenge (DBPCFC). Objectives. To investigate the diagnostic value of these techniques for confirmation of a suspected milk allergy in bronchial asthma patients. Methods. In 54 asthmatics with a positive history and/or positive skin tests for milk the 54 OFICH, and DBPCFC, were performed in combination with spirometry. Results. The 54 patients developed 39 positive late asthmatic responses (LAR) and 15 negative asthmatic responses to OFICH and 40 positive LARs and 14 negative responses to DBPCFC. The overall correlation between the OFICH and DBPCFC was statistically significant (P < 0.01). Conclusions. This study has confirmed the existence of LAR to milk ingestion performed by OFICH and DBPCFC in combination with spirometry. The results obtained by both the techniques did not differ significantly. The OFICH with natural food combined with monitoring of objective parameter(s), such as spirometry, seems to be a suitable method for detection of the food allergy in asthmatics. The DBPCFC can be performed as an additional check, if necessary.

Teste de provocação oral aberto na confirmação de alergia ao leite de vaca mediada por IgE: qual seu valor na prática clínica?

OBJETIVO: Revisar os principais protocolos de padronização para o teste de provocação oral aberto aplicado a crianças com suspeita de alergia ao leite de vaca mediada por imunoglobulina E. FONTES DE DADOS: Foram selecionados artigos publicados, nos últimos dez anos, nas bases de dados Medline, Lilacs e SciELO, utilizando-se os descritores de assunto: "hipersensibilidade alimentar", "leite de vaca", "alergia ao leite de vaca", "teste de provocação oral", "crianças" e "diagnóstico". SÍNTESE DOS DADOS: O teste de provocação oral é o método mais fidedigno para estabelecer ou excluir o diagnóstico de alergia alimentar e sua forma aberta pode ser a primeira opção, quando apenas reações objetivas são esperadas. O local para realizar o teste deve possuir todos os recursos para tratamento de emergência. Como preparo, o paciente deve seguir dieta de exclusão do alimento suspeito e descontinuar o uso de medicamentos que possam interferir no resultado do teste. Habitualmente, utilizam-se 8 a 10g de leite em pó ou 100mL de leite fluido, oferecidos em volumes progressivos, a intervalos de dez a 60 minutos. Apesar da rigidez do método, ainda existem situações em que há dificuldade de interpretação dos resultados; por isso, médicos bem treinados devem aplicar o teste, sendo cautelosos ao julgarem as reações. CONCLUSÕES: Mesmo considerando as limitações que dificultam a aplicação do teste de provocação oral na prática clínica, a implementação do teste nos serviços de saúde poderia reduzir diagnósticos falsos-positivos de alergias.

Prevalence of challenge-proven IgE-mediated food allergy using population-based sampling and predetermined challenge criteria in infants

BACKGROUND

Several indicators suggest that food allergy in infants is common and possibly increasing. Few studies have used oral food challenge to measure this phenomenon at the population level.

OBJECTIVE

To measure the prevalence of common IgE-mediated childhood food allergies in a population-based sample of 12-month-old infants by using predetermined food challenge criteria to measure outcomes.

METHODS

A sampling frame was used to select recruitment areas to attain a representative population base. Recruitment occurred at childhood immunization sessions in Melbourne, Australia. Infants underwent skin prick testing, and those with any sensitization (wheal size ≥ 1 mm) to 1 or more foods (raw egg, peanut, sesame, shellfish, or cow's milk) were invited to attend an allergy research clinic. Those who registered a wheal size ≥ 1 mm to raw egg, peanut, or sesame underwent oral food challenge.

RESULTS

Amongst 2848 infants (73% participation rate), the prevalence of any sensitization to peanut was 8.9% (95% CI, 7.9-10.0); raw egg white, 16.5% (95% CI, 15.1-17.9); sesame, 2.5% (95% CI, 2.0-3.1); cow's milk, 5.6% (95% CI, 3.2-8.0); and shellfish, 0.9% (95% CI, 0.6-1.5). The prevalence of challenge-proven peanut allergy was 3.0% (95% CI, 2.4-3.8); raw egg allergy, 8.9% (95% CI, 7.8-10.0); and sesame allergy, 0.8% (95% CI, 0.5-1.1). Oral food challenges to cow's milk and shellfish were not performed. Of those with raw egg allergy, 80.3% could tolerate baked egg.

CONCLUSION

More than 10% of 1-year-old infants had challenge-proven IgE-mediated food allergy to one of the common allergenic foods of infancy. The high prevalence of allergic disease in Australia requires further investigation and may be related to modifiable environmental factors.

Time trends in the prevalence of peanut allergy: three cohorts of children from the same geographical location in the UK

BACKGROUND

This article investigated the prevalence of peanut allergy in three cohorts of children born in the same geographical location, Isle of Wight, UK and seeks to determine whether the prevalence of peanut allergy has changed between 1994 and 2004.

METHODS

Three cohorts of children (age 3-4 years) born on the Isle of Wight, were assessed for peanut allergy and the outcomes compared: Cohort A: Born in 1989; reviewed at 4 years of age (n = 2181). Cohort B: Born between 1994 and 1996; reviewed between 3 and 4 years of age (n = 1273). Cohort C: Born between 2001 and 2002; reviewed at 3 years of age (n = 891).

RESULTS

Peanut sensitization increased significantly from 1.3% in Cohort A to 3.3% (P = 0.003) in Cohort B before falling back to 2.0% in Cohort C (P = 0.145). Similarly, clinical peanut allergy increased significantly from 0.5% in Cohort A to 1.4% (P = 0.023) in Cohort B, with a subsequent fall to 1.2% in Cohort C (P = 0.850).

CONCLUSIONS

Our data from three cohorts of 3- to 4-year-old children born in the same geographical area shows that peanut allergy prevalence has changed over time. Peanut sensitization and reported allergy in children born in 1994-1996 increased from 1989 but seems to have stabilized or slightly decreased since the late 1990s, although not significant.

Food-dependent Exercise-induced Anaphylaxis – A Review of 5 Cases

Introduction: Food-dependent exercise-induced anaphylaxis (FDEIA) is an uncommon and under-recognised syndrome that clinicians may not consider in a patient presenting with ana- phylaxis. Clinical Picture: We describe here 5 patients aged 9 to 20 years old who presented at a local tertiary hospital over a 2-year period from August 2006 to July 2008. All presented with urticaria, 4 were hypotensive, 2 had angioedema and another 2 had dyspnoea. The symptoms occurred between 15 and 150 minutes (mean, 81) after exercising and consuming various food. All had consumed shellfish. All patients were admitted with the diagnosis of anaphylaxis of undefined aetiology. Diagnosis of FDEIA was only reached upon referral to an allergist. Treat- ment and Outcome: Patients were treated with standard medicines for anaphylaxis including adrenaline, antihistamines, steroids and fluid flushes. Symptoms resolved in 2 to 3 days with no further episodes. At discharge, patients were prescribed epinephrine auto-injectors and given written anaphylaxis management plans. Conclusions: More public awareness and strategies to ensure accurate diagnosis and management of this condition are necessary. Key words: Anaphylaxis, Epinephrine, Exercise, Food

Clinical practice. Diagnosis and treatment of cow's milk allergy

INTRODUCTION

Cow's milk allergy (CMA) is thought to affect 2-3% of infants. The signs and symptoms are nonspecific and may be difficult to objectify, and as the diagnosis requires cow's milk elimination followed by challenge, often, children are considered cow's milk allergic without proven diagnosis.

DIAGNOSIS

Because of the consequences, a correct diagnosis of CMA is pivotal. Open challenges tend to overestimate the number of children with CMA. The only reliable way to diagnose CMA is by double-blind, placebo-controlled challenge (DBPCFC).

THERAPY

At present, the only proven treatment consists of elimination of cow's milk protein from the child's diet and the introduction of formulas based on extensively hydrolysed whey protein or casein; amino acid-based formula is rarely indicated. The majority of children will regain tolerance to cow's milk within the first 5 years of life.

CONCLUSIONS

Open challenges can be used to reject CMA, but for adequate diagnosis, DBPCFC is mandatory. In most children, CMA can be adequately treated with extensively hydrolysed whey protein or casein formulas.

Gastrointestinal manifestations of food allergy

Gastrointestinal food allergies are not rare in infants and children. Symptoms include vomiting, reflux, abdominal pains, diarrhea and constipation. Clinical diagnosis requires the exclusion of nonimmunologic diseases that have similar gastrointestinal symptoms. In food allergy, the immune reactions involved can be immunoglobulin (Ig)E-mediated, cell-mediated or both. Symptoms in other target organs are common in cases of IgE-mediated disorders, but not in the cell-mediated disorders in which symptoms are usually localized to the gut. Diagnosis utilizes detailed medical history, clinical evaluation, skin testing, food-specific IgE antibodies, responses to elimination diet and oral food challenges. Endoscopic biopsies are essential in cell-mediated disorders and allergic eosinophilic gastropathies. Treatment includes avoidance of the offending food by a restriction diet in children and the use of hydrolyzed or amino acid-based formulas in young infants. Topical and/or systemic corticosteroids can also be used in eosinophilic esophagitis. Current research is aimed at improving the diagnostic tools and therapeutic options available to patients.

The diagnosis of food allergy in children

PURPOSE OF REVIEW

To give an update about the optimal diagnostic work-up for children with suspected food allergy.

RECENT FINDINGS

Food allergy has become a very severe health problem not only for many children and parents, but also for the entire medical and paramedical community. The financial and social costs related to these conditions are increasing, but, contemporarily, basic and clinical research are deeply involved in the search of possible solutions to facilitate the management of these patients.

SUMMARY

Food allergy is defined as an abnormal immunological reaction to food proteins, which causes an adverse clinical reaction. Over 90% of food allergies in childhood are caused by eight foods: cow's milk, hen's egg, soy, peanuts, tree nuts, wheat, fish and shellfish. The evaluation of a child with suspected food allergy includes detailed medical history, physical examination, screening tests and response to elimination diet and to oral food challenge. None of the screening tests, alone or in combination, can definitely diagnose or exclude it. The main principle of food allergy management is avoidance of the offending antigen. An incorrect diagnosis is likely to result in unnecessary dietary restrictions, which, if prolonged, may adversely affect the child's nutritional status and growth.