Identifying Region-Specific Allergy Sensitization Clusters to Optimize Diagnosis and Reduce Costs.

OBJECTIVE: To delineate quantitatively the allergen sensitization patterns in a large pediatric cohort and inform the selection of a region-specific panel of allergen tests for timely and cost-effective in vitro atopy screening. STUDY DESIGN: IgE levels for specific allergens from patients in the Texas Children's Health System were analyzed retrospectively. Statistical and network analyses were conducted to reveal sensitization patterns. RESULTS: Network analysis of 114 distinct allergens among 12 065 patients identified 2 main groups of allergens: environmental and food. Approximately 67.5% of patients were sensitized to environmental allergens, 47.2% to food allergens, and 7.3% to at least 1 allergen from both groups. We identified a novel panel of 13 allergens that could detect sensitization in 95% of patients, whereas panels of 7 allergens within each category effectively identified sensitization in 95% of patients with specific sensitivities. This data-driven approach is estimated to reduce overall testing costs by 52%. In agreement with literature, we observed correlations among allergens within specific categories, such as pollen, shellfish, nuts, and dairy allergens. CONCLUSIONS: This study provides insights into allergen sensitization patterns informing an algorithmic testing approach tailored for primary care settings. The use of a region and population-specific test panel can efficiently identify atopy, leading to more targeted testing. This strategy has the potential to refine laboratory testing, reduce costs, and improve the appropriateness of referrals to allergy specialists, ultimately enhancing diagnostic accuracy and resource allocation.

Assessment of intracellular zinc levels in infants with food protein-induced allergic proctocolitis.

BACKGROUND: Food protein-induced allergic proctocolitis (FPIAP) is characterized by bloody stools in well-appearing infants. Zinc is a micronutrient that plays a crucial role in immune modulation and is essential for cellular function during immune response. Although there are studies on the assessment of intracellular zinc levels in allergic diseases, no data is available on erythrocyte zinc levels of patients with FPIAP. OBJECTIVE: This study aimed to assess the erythrocyte zinc levels of children with allergic proctocolitis and compare zinc levels with clinical and demographic characteristics. METHODS: This was a case-control study that prospectively compared 50 patients with FPIAP and 50 healthy children without malnutrition. The erythrocyte zinc levels of children were determined using atomic absorption spectrophotometry. RESULTS: Fifty patients with FPIAP, including 28 (51%) girls, with median age of 7.1 ± 2.9 (3-14) months and 50 healthy children, including 26 (53.1%) girls, with median age of 7.7 ± 2.8 (3-13) months were included in the study. Seventy percent (n = 35) of the patients with FPIAP started to have symptoms while they were exclusively breastfeeding. Offending allergen foods were cow's milk (78%), egg (40%), sesame (10%), hazelnut (8%), almond (6%), beef (6%), and peanuts (6%, n = 3). Intracellular (erythrocyte) zinc levels in patients with FPIAP were lower than in the healthy control group (495.5 ± 134 µg/dL, 567.3 ± 154.4 µg/dL, respectively, P = 0.01). Patients with FPIAP aged younger than 6 months had lower intracellular zinc levels compared with those aged above 6 months (457 ± 137 µg/dL; 548 ± 112 µg/dL, respectively, P = 0.01). There was no relationship between zinc levels and time of symptom onset, presence of concomitant disease, being allergic to multiple foods, and family history of atopy (P > 0.05). CONCLUSIONS: FPIAP is a food allergy with limited information on its pathogenesis. Considering the beneficial effects on gastrointestinal system epithelia, zinc may be involved in the pathogenesis of FPIAP. Future comprehensive prospective research on this subject is of importance.

Allergenic risk assessment of cowpea and its cross-reactivity with pea and peanut.

BACKGROUND: Novel protein sources can represent a risk for allergic consumers. The aim of this study was to evaluate the allergenicity of cowpea (Vigna unguiculata), an increasingly consumed legume and potential new industrial food ingredient which may put legume-allergic patients at risk. METHODS: Children with allergy to legumes associated to peanut (LP group: n = 13) or without peanut allergy (L group: n = 14) were recruited and sensitization to several legumes including cowpea was assessed by prick tests and detection of specific IgE (sIgE). Cowpea protein extract was analyzed by SDS-PAGE and immunoblotting, IgE-reactive spots were subjected to mass spectrometry. IgE-cross-reactivity between cowpea, pea, and peanut was determined using ELISA inhibition assays. Basophil activation tests were performed to evaluate sensitivity and reactivity of patient basophils toward legumes. RESULTS: Prick tests and sIgE levels to cowpea were positive in 8/14 and 4/13 patients of the L group and in 9/13 and 10/13 patients of the LP group, respectively. Four major IgE-binding proteins were identified as vicilins and seed albumin. Cowpea extract and its vicilin fraction strongly inhibited IgE-binding to pea and peanut extract. Peanut, lentil, and pea were the strongest activators of basophils, followed by cowpea, soybean, mung bean, and lupin. CONCLUSION: A majority of patients with legume allergy were sensitized to cowpea proteins. Four novel allergens were identified in cowpea, among which storage proteins were playing an important role in IgE-cross-reactivity, exposing legume-allergic patients to the risk of clinical cross-reactivity to cowpea and thus adding cowpea to the group of nonpriority legumes that are not subjected to allergen labeling such as chickpea, pea, and lentil.

Out-of-hospital health care costs of childhood food allergy in Australia: A population-based longitudinal study.

BACKGROUND: Australia has one of the highest prevalence of childhood food allergy in the world, but there are no data on its economic burden in Australia. METHODS: We used data from the HealthNuts study, a population-based longitudinal study undertaken in Melbourne, Australia. Infants were recruited at age 12 months between Sept 2007 and Aug 2011 with food allergy diagnosed using oral food challenges. Health care costs of out-of-hospital services were collected through data linkage to Australia's universal health insurance scheme Medicare. Two-part model was used to compare costs after controlling for potential confounders. RESULTS: 2919 children were included, and 390 (13.4%) had challenge-confirmed food allergy at age 1 year. Compared with children without food allergy, children with food allergy had significantly higher costs for GP visits, specialist visits, tests, and prescriptions in the first four years of life. The total Medicare cost associated with food allergy from age 1 to 4 years was estimated to be AUD$889.7 (95% CI $566.1-$1188.3) or €411.0 (95% CI €261.5-€549.0) per child. This was projected into an annual Medicare cost of AUD$26.1 million (95% CI $20.1-$32.3 million) or €12.1 (95% CI €9.3-€14.9 million) based on population size in 2020. CONCLUSIONS: Childhood food allergy causes considerable Medicare costs for out-of-hospital services in the first four years after birth in Australia. These findings can help anticipate the financial impact on the health care system associated with childhood food allergy, act as a useful costing resource for future evaluations, and inform management of childhood food allergy internationally.

Needs Assessment for Eosinophilic Esophagitis Education in School Nurses.

Over the past 2 decades, eosinophilic esophagitis (EoE) has become increasingly recognized as a common cause of gastrointestinal morbidity in children. A mainstay of treatment is food avoidance, which must be implemented in both the home and school settings for school-aged children. The aim of this study is to assess school nurses' familiarity with EoE with regard to food avoidance and treatment in the school setting. We conducted a 19-question online survey of 60 school nurses (elementary through high school) recruited from Dauphin, Lebanon, and Lancaster Counties in Pennsylvania. Results indicated that 62% of respondents were familiar with EoE. However, only 22% felt comfortable distinguishing between symptoms of EoE and food-dependent anaphylaxis. Almost all respondents (97%) were interested in learning more about EoE. We report significantly increased familiarity with food-dependent anaphylaxis in comparison with EoE among school nurses. There is an interest and need for increasing education on EoE.

A Prospective Assessment of Clinical Characteristics and Responses to Dietary Elimination in Food Protein-Induced Allergic Proctocolitis.

BACKGROUND: Some aspects of diagnostic elimination/challenge diets in food protein-induced allergic proctocolitis (FPIAP) are still poorly defined. OBJECTIVE: This study investigated the symptom spectrum, time required for resolution of each symptom, triggering foods, and risk factors for multiple food allergies (MFA) in FPIAP. METHODS: Infants referred with visible blood in stool were enrolled after etiologies other than FPIAP had been excluded. Laboratory evaluation, clinical features, and elimination/challenge steps were performed prospectively during diagnostic management. RESULTS: Ninety-one of 102 infants (53 boys) were diagnosed with FPIAP. Eleven children did not bleed during challenges. Visible blood in stool began before 2 months of age in 63.6% of the infants not diagnosed with FPIAP, compared with 18.9% of the patients with FPIAP (P = .003). Offending foods were identified as cow's milk (94.5%), egg (37.4%), beef (10.9%), wheat (5.5%), and nuts (3.3%). MFA was determined in 42.9% of patients. Multivariate logistic regression analysis identified atopic dermatitis (AD) (odds ratio [OR]: 2.98, 95% confidence interval [CI]: 1.18-7.55, P = .021) and an eosinophil count ≥300 cells/µL (OR: 2.72, 95% CI: 1.09-6.80, P = .032) as independent risk factors for MFA. Blood and mucus in stool disappeared in a median 3 days (interquartile range [IQR]: 1-14.5 days) and 30 days (IQR: 8-75 days), respectively. CONCLUSIONS: A tendency to transient bleeding occurs in infants who present with bloody stool before 2 months of age. A 2-week duration of elimination for blood in stool is sufficient to reach a judgment of suspected foods for FPIAP. Mucus in stool is the last symptom to disappear. Concurrent AD suggests a high probability of MFA in FPIAP.

Peanut Can Be Used as a Reference Allergen for Hazard Characterization in Food Allergen Risk Management: A Rapid Evidence Assessment and Meta-Analysis.

Regional and national legislation mandates the disclosure of "priority" allergens when present as an ingredient in foods, but this does not extend to the unintended presence of allergens due to shared production facilities. This has resulted in a proliferation of precautionary allergen ("may contain") labels (PAL) that are frequently ignored by food-allergic consumers. Attempts have been made to improve allergen risk management to better inform the use of PAL, but a lack of consensus has led to variety of regulatory approaches and nonuniformity in the use of PAL by food businesses. One potential solution would be to establish internationally agreed "reference doses," below which no PAL would be needed. However, if reference doses are to be used to inform the need for PAL, then it is essential to characterize the hazard associated with these low-level exposures. For peanut, there are now published data relating to over 3000 double-blind, placebo-controlled challenges in allergic individuals, but a similar level of evidence is lacking for other priority allergens. We present the results of a rapid evidence assessment and meta-analysis for the risk of anaphylaxis to a low-level allergen exposure for priority allergens. On the basis of this analysis, we propose that peanut can and should be considered an exemplar allergen for the hazard characterization at a low-level allergen exposure.

Mapping the Food Allergy Quality of Life Questionnaire Parent Form onto the Short-Form Six-Dimensions version 2.

BACKGROUND: The Food Allergy Quality of Life Questionnaire Parent Form (FAQLQ-PF) is the most widely used quality of life questionnaire in food allergy. The objective of this study was to develop a mapping algorithm to convert FAQLQ-PF scores into health state utilities. METHODS: The Short-Form Six-Dimensions version 2 (SF-6Dv2) and FAQLQ-PF questionnaires were collected from an academic center oral immunotherapy referral cohort. Utility estimates were derived from the SF-6Dv2 using the food allergy preference set. Candidate mapping algorithm models were developed using seven regression methods starting from either the total average score, the average scores of each of the three domains or the individual item scores of FAQLQ-PF. The process was repeated twice, including only section A, common to all age groups, or including all age-applicable sections of the FAQLQ-PF. The mean absolute error (MAE) and root mean squared error (RMSE) were used to select the best fitting model. An independent cohort from a previous national online survey was used for external validation. RESULTS: In the index cohort, 1000 of 1257 respondents had completed both questionnaires. The lowest MAE (0.0791) and RMSE (0.1020) were recorded when entering individual item scores in a categorical regression model. The model including only FAQLQ-PF section A was found to be most consistent when tested in the external validation cohort (n = 248) (MAE of 0.0898). CONCLUSION: The FAQLQ-PF was mapped onto SF-6Dv2 utilities with good predictive accuracy in two independent cohorts. This will enable calculation of health utility for cost-effectiveness analyses in food allergy.

ASSESSMENT OF ALLERGIES TO FOOD AND ADDITIVES IN PATIENTS WITH ANGIOEDEMA, BURNING MOUTH SYNDROME, CHEILITIS, GINGIVOSTOMATITIS, ORAL LICHENOID REACTIONS, AND PERIORAL DERMATITIS.

Oral cavity and perioral area are constantly exposed to a variety of antigens, including food and additives, which have a potential role in the development of different oral mucosal and perioral cutaneous diseases since they can cause hypersensitivity reactions. Oral and perioral diseases mainly include angioedema, burning mouth syndrome, cheilitis, gingivostomatitis, oral lichenoid reactions, and perioral dermatitis. Previous studies were focused on delayed-type oral allergies by performing patch testing but did not include tests for immediate-type allergic reactions. Therefore, the objective of this study was to determine common nutritive and additive allergens in the prevalent oral and perioral diseases by using skin prick tests. Our study evaluated 230 participants, i.e. 180 patients with oral/perioral diseases (angioedema, burning mouth syndrome, cheilitis, gingivostomatitis, oral lichenoid reactions, and perioral dermatitis), and 50 healthy control subjects. The results of skin prick tests showed that immediate-type allergic reactions to food and additives were mostly seen in patients with burning mouth syndrome (40%) and cheilitis (33.3%), whereas allergies were least frequently observed in perioral dermatitis (10%) and gingivostomatitis (20%). Fruits, mushrooms, and vegetables were the most frequent causes of nutritive allergies in oral and perioral diseases. The most commonly identified additive allergens were glutaraldehyde, citric acid, and sodium glutamate. Study results suggest the possible association with nutritive and additive allergies be considered in cases of persistent oral mucosal or perioral skin disease accompanied by respective medical history.

Component resolved diagnosis and risk assessment in food allergy.

Allergy testing should only be performed in the context of the clinical history as history provides the cornerstone of diagnosis. In food allergy, some allergy tests often give rise to false positive results and thus can lead to unnecessary avoidance or delay on foods introduction. The use of Component Resolved Diagnosis in combination with conventional sensitization testing improves analytical and diagnostic performance and can lead to the reduction of diagnostic oral food challenges. Component Resolved Diagnosis can be helpful in identifying some risks for the allergic child. Molecular diagnosis can help also in predicting the development of the allergy march, in severe reactions (lipid transfer protein, seed storage proteins, etc.) in food allergy and for potential clinical cross-reactivity.

Demystifying α-gal syndrome: identification and risk management in the perioperative setting.

PURPOSE OF REVIEW: α-Gal syndrome is among a vexing perioperative consideration for anesthesiologists. Commonly referred to as 'red meat allergy', α-Gal syndrome is precipitated by a lone star tick bite resulting in the formation of immunoglobulin E (IgE) antibodies against the tick salivary glycoproteins and noncatarrhine mammalian tissue. RECENT FINDINGS: Up to 20% of the population in the southeastern United States may test positive for IgE antibodies to α-Gal. Increasingly, recognition of α-Gal syndrome as an immune response to red meat consumption and certain drugs, many of which may be administered within the perioperative period, has led to greater awareness of the insidious nature of its presentation - from mild urticaria and gastrointestinal symptoms to severe anaphylaxis. SUMMARY: With the increasing prevalence and identification of α-Gal syndrome, a safe and tailored perioperative process is needed to integrate a pathway that involves multidisciplinary communication, robust information sharing platform, and a structured peri-procedure management.

Cost-Effectiveness of Food Allergy Interventions in Children: A Systematic Review of Economic Evaluations.

OBJECTIVES: To identify published economic evaluations of interventions aimed at preventing, diagnosing, or treating food allergies in children. METHODS: We examined economic evaluations published from 2000 to 2019. Data analyzed included: food allergy type, study population/setting, intervention/comparator, and economic evaluation details. Quality assessment used reporting and economic modeling checklists. Two reviewers simultaneously undertook article screening, data extraction, and quality assessment. RESULTS: 17 studies were included: 8 peanut allergy (PA) studies, 8 cow's milk allergy (CMA) studies, and 1 egg allergy (EA) study. All PA studies reported incremental costs per quality-adjusted life-year gained for diagnostic strategies, management pathways for peanut exposure, and immunotherapies. Immunotherapies rendered inconsistent cost-effectiveness results. CMA studies reported costs per symptom-free day or probability of developing CMA tolerance. Cost-effectiveness of extensively hydrolyzed casein formula for CMA treatment was consistently demonstrated. Early introduction of cooked egg in first year of life dominated all EA prevention strategies. Quality assessment showed average noncompliance for 3.5 items/study (range 0-11) for modeling methods and 3.4 items/study (range 0-8) for reporting quality. Key quality concerns included limited justification for model choice, evidence base for model parameters, source of utility values, and representation of uncertainty. CONCLUSION: Recent cost-effectiveness literature of interventions in PA, CMA, and EA is limited and diverse. Interventions for diagnosis and treatment of CMA and prevention of EA were generally cost-effective; however, results for PA were variable and dependent on effectiveness and utility values used. There is a need to expand economic evaluation of interventions for childhood food allergy and to improve methods and reporting.

Deriving health utility indices from a food allergy quality-of-life questionnaire.

BACKGROUND: The Food Allergy Quality-of-Life Questionnaire-Parent Form (FAQLQ-PF) is widely used to assess food allergy-specific health-related quality of life (FAQL), but cannot be used directly in cost-utility analyses, which require health state utility (HSU) scores. Currently, limited evidence is available regarding the HSU of food-allergic children/adolescents. This study aimed to develop mapping algorithms from the FAQLQ-PF onto HSU scores generated by generic, preference-based, health-related quality-of-life (HRQL) instruments. METHODS: Caregivers of children aged 7 to 17 years with a clinician diagnosis of IgE-mediated food allergy, recruited via Allergy & Anaphylaxis Australia, completed an online FAQLQ-PF questionnaire and proxy generic preference-based pediatric instruments (Assessment of Quality of Life [AQoL]-6D and Child Health Utility 9D [CHU9D]). Optimal statistical methods were based on series of goodness-of-fit statistics. RESULTS: Mean FAQLQ-PF total score, AQoL-6D, and CHU9D utility scores of 238 food-allergic children/adolescents were 3.49 (SD: 1.41), 0.78 (SD: 0.22), and 0.74 (SD: 0.22), respectively. The Spearman correlation coefficients of FAQLQ-PF with AQoL-6D and CHU9D were rho = -0.56 and rho = -0.45, respectively. Optimal mapping algorithms were generated from selected FAQLQ-PF items, mapped onto AQoL-6D or CHU9D utility scores, with AQoL-6D demonstrating better performance. CONCLUSIONS: This study generated mapping algorithms to help facilitate the use of FAQLQ-PF for cost-utility analyses, which are essential for health economic evaluation. External validation of the reported mapping algorithms is warranted.

Addressing risk management difficulties in children with food allergies.

Risk is a concept inherent in every medical procedure. It can be defined as the probability of an adverse event in a defined population over a specified period of time. In the frame of food allergy management, it might be related to a diagnostic procedure, a treatment, or the consumption of foods. The risk of an adverse event can also be augmented by individual factors. This rostrum article discusses various aspects faced by children with food allergies in the light of risk, and their practical implications. Identifying personal risks for severe reaction, such as unstable asthma, and correcting them whenever possible also contribute to a reduction of the risk inherent to food allergy. Among the facets discussed, oral food challenges (OFC) are the most common diagnostic procedures implying an inherent risk. The risk of OFCs can be minimized by correct indication and timing of the test, a safe setting, as well as by ensuring that the patient is otherwise well without potential stressor potentially increasing the risk of a more severe reaction. Oral immunotherapy (OIT) has been studied as a potential treatment for increasing the threshold dose for reaction, and thus reducing the risk of accidental reaction. Nevertheless, the procedure is not devoid of risk as the patients may and do often react during the course of the procedure. Ingestion of trace amounts in processed foods, mainly in community settings such as restaurants, schools, or day care, represents a potential risk of reactions, although for a minority of patients. Precautionary allergen labeling (PAL) is a widespread strategy to reduce the potential risk of reactions due to traces. However, PAL is currently inefficient due to inconsistent labeling, also not indicating a clear maximum amount possibly present in the manufactured food. Finally, cost-effectiveness needs to be considered in risk management, as many risk reduction procedures are clearly not cost-effective.

Assessment of IgE- and cell-mediated immunity in pediatric patients with eosinophilic esophagitis.

Summary: Eosinophilic esophagitis (EoE) is a chronic allergen/immune-mediated disease leading to esophageal dysfunction. Food allergens play critical roles in the pathogenesis and treatment of EoE via different mechanisms. This study aimed to present the characteristics and evaluate the ability of skin prick test (SPT), skin prick to prick test (SPP) (IgE-mediated), and atopic patch test (APT) (cell-mediated) individually or simultaneously to diagnose food allergy in patients suffering from EoE. This prospective study was conducted on 58 patients with EoE. Seven patients (12.1%) were positive to only one, 3 (5.2%) were simultaneously positive to two, and 32 (55.2%) were simultaneously positive to three tests. Single and double sensitizations were totally 10.4% in IgE-mediated reactions, while 36.5% in cell-mediated reactions. In contrast, poly sensitization (> 2 allergens) was 51.7% in IgE-mediated tests and 20.7% in the cell-mediated test. Multiple sensitization findings showed egg white, milk, yolk, and soy were the most frequent allergens. Our findings indicate that EoE is early onset and associated with multiple food sensitizations, particularly via IgE-mediated mechanisms. These immune-mediated responses encompass both IgE-mediated (SPT and SPP) and cell-mediated (APT) reactions simultaneously not individually. Therefore, employing multiple assays may strengthen the diagnosis of food sensitization.

SF-6Dv2 preference value set for health utility in food allergy.

BACKGROUND: The lack of a value set allowing the calculation of QALY is an important limitation when establishing the value of emerging therapies to treat food allergy. The aim of this study was to develop a Short-Form Six-Dimension version 2 (SF-6Dv2) preference value set for the calculation of health utility from the Canadian food-allergic population. METHODS: Two hundred ninety-five parents of patients aged 0-17 years old and 154 patients aged 12 years old and above with food allergy were recruited in clinic and online. Participants were asked to complete a self-administered online questionnaire including generic health-related quality of life questionnaires. Various health states described by the SF-6Dv2 were valued with time-trade-off and discrete choice experiments. Data from elicitation techniques were combined using the hybrid regression model. RESULTS: A total of 241 parents and 125 patients performed 3904 time-trade-off and 5112 discrete choice experiments. Utility decrements were estimated for each level of each SF-6Dv2 dimension. Utility values calculated based on the validated preference set were in average 0.15 lower (95%CI: 0.12-0.18) and were poorly correlated (R2  = 0.46) with those derived from the EQ-5D-5L generic questionnaire in the same cohort. CONCLUSION: A representative preference value set for patients with food allergy was determined using the SF-6Dv2 generic questionnaire. This adapted preference set will contribute to improve the validity of future utility estimates in this population for the appraisal of upcoming potentially impactful but sometimes costly therapies.

Guideline-informed care among Medicaid-enrolled children with food allergy.

OBJECTIVES: To describe food allergy (FA)-related service utilization and identify factors associated with guideline-informed care among Medicaid-enrolled US children with FA. STUDY DESIGN: Retrospective cohort study. METHODS: We used the 2012 Medicaid Analytic eXtract files to identify children with an FA diagnosis. FA-related services including outpatient allergist visits, emergency department (ED) visits, epinephrine autoinjector prescription fills, and diagnostic testing were identified. Factors associated with services were assessed using logistic regression. Kaplan-Meier survival curves evaluated the time to guideline-informed care, and proportional hazard models determined associated socioeconomic characteristics. RESULTS: There were 64,276 Medicaid-enrolled children younger than 20 years who had at least 1 claim with an FA diagnosis in 2012. Minority children and those living in a high-poverty county were less likely to have visited an allergist for FA or received diagnostic testing but more likely to have an FA-related ED visit compared with White children and those not living in a high-poverty county. Survival analyses found that of children seen for FA-related primary care or an ED visit, rates of allergist follow-up visits were 21% and 17%, respectively, and rates of epinephrine autoinjector prescription fills were 39% and 41%. Significant associations with guideline-informed care were found by race/ethnicity, dense population, and high-poverty counties. CONCLUSIONS: Although guideline-informed FA care includes follow-up with an allergist and epinephrine autoinjector prescription, this study finds low probabilities of timely service utilization after medical visits, as well as socioeconomic disparities in care.

Mobile Phone Apps for Food Allergies or Intolerances in App Stores: Systematic Search and Quality Assessment Using the Mobile App Rating Scale (MARS).

BACKGROUND: Food allergies and intolerances are increasing worldwide, and mobile phone apps could be a promising tool for self-management of these issues. OBJECTIVE: This study aimed to systemically search and assess food allergy or intolerance apps in app stores using the multidimensional Mobile App Rating Scale (MARS) to rate the objective and subjective quality and to identify critical points for future improvements. METHODS: This systematic search identified apps through the keywords "food allergy," "food intolerance," and "allergens" in English, Spanish, and Italian in the Apple App Store (iOS) and Google Play Store (Android). The inclusion criteria were a user star rating of ≥3 (of 5 stars) to limit the selection to the most highly rated apps; ≥1000 reviews as an indicator of reliability; and the most recent update performed up to 2017. Then, the apps were divided according to their purpose (searching for allergen-free "food products," "restaurants," or recipes in "meal planners") and evaluated on a scale of 1 to 5 points using the MARS in terms of (1) app classification category with a descriptive aim; (2) app subjective and objective quality categories comprised of engagement, functionality, esthetics, and information sections (Medline was searched for eligible apps to check whether they had been tested in trials); and (3) an optional app-specific section. Furthermore, the output and input features were evaluated. Differences between MARS sections and between app purposes and correlations among MARS sections, star ratings, and numbers of reviews were evaluated. RESULTS: Of the 1376 apps identified, 14 were included: 12 related to food allergies and intolerances that detect 2-16 food allergens and 2 related only to gluten intolerance. The mean (SD) MARS scores (maximum 5 points) were 3.8 (SD 0.4) for objective quality, highlighting whether any app had been tested in trials; 3.5 (SD 0.6) for subjective quality; and 3.6 (SD 0.7) for the app-specific section. Therefore, a rating ≥3 points indicated overall acceptable quality. From the between-section comparison, engagement (mean 3.5, SD 0.6) obtained significantly lower scores than functionality (mean 4.1, SD 0.6), esthetics (mean 4, SD 0.5), and information (mean 3.8, SD 0.4). However, when the apps were compared by purpose, critical points were identified: meal planner apps showed significantly higher engagement (mean 4.1, SD 0.4) than food product (mean 3.0, SD 0.6; P=.05) and restaurant (mean 3.2, SD 0.3; P=.02) apps. CONCLUSIONS: In this systematic search of food allergy or intolerance apps, acceptable MARS quality was identified, although the engagement section for food product and restaurant purpose apps should be improved and the included apps should be tested in trials. The critical points identified in this systematic search can help improve the innovativeness and applicability of future food allergy and intolerance apps.