A nationwide survey of non-IgE-mediated gastrointestinal food allergies in neonates and infants.

BACKGROUND: Non-IgE-mediated gastrointestinal food allergies (non-IgE-GIFAs) seem to be increasing rapidly worldwide. However, nationwide studies have been limited to food-protein-induced enterocolitis (FPIES) and food-protein-induced allergic proctocolitis (FPIAP), with little attention to other non-IgE-GIFA subgroups. The aim of this study was to elucidate the clinical features of all patients with non-IgE-GIFAs, not just certain subgroups. METHODS: We conducted a nationwide cross-sectional survey of non-IgE-GIFAs in Japan from April 2015 through March 2016. A questionnaire was sent to hospitals and clinics throughout Japan. The questionnaire asked about the number of physician-diagnosed non-IgE-GIFA patients, the status of fulfillment of the diagnostic criteria, tentative classification into 4 clusters based on the initial symptoms, the day of onset after birth, complications, and the suspected offending food(s). RESULTS: The response rate to that questionnaire was 67.6% from hospitals and 47.4% from clinics. Analyses were conducted about "diagnosis-probable" patient cohort (n = 402) and the "diagnosis-confirmed" patients (n = 80). In half of the reported non-IgE-GIFA patients, onset occurred in the neonatal period. The patients were evenly distributed among 4 non-IgE-GIFA clusters. In Cluster 1, with symptoms of vomiting and bloody stool, the onset showed a median of 7 days after birth, which was the earliest among the clusters. Cow's milk was the most common causative food. CONCLUSIONS: In half of the patients, the onset of non-IgE-GIFAs was in the neonatal period. This highlights the importance of studying the pathogenesis in the fetal and neonatal periods.

What is Known About Cow's Milk Protein Allergy in Preterm Infants?

Background: Cow's milk protein allergy (CMPA) is well described in term infants, as opposed to preterm infants. In preterm infants, CMPA shares many gastrointestinal symptoms with necrotizing enterocolitis (NEC). Objectives: To evaluate the presentation of CMPA in preterm infants and to investigate the different diagnostic and therapeutic options. Materials and Methods: We searched for the relevant literature using the medical databases PubMed, Web of Science, and the Cochrane Library. We performed a post hoc analysis on the 25 case reports included in this study. Results: Literature was scarce and heterogeneous. The majority of preterm infants with CMPA were exposed to bovine-based milk proteins before the development of symptoms. The most common clinical manifestations were bloody stools, vomiting, and abdominal distension. Of the 25 cases, only 7 (28%) retained human milk in their diet after diagnosis. In the larger studies, no study has human milk as primary feeding choice after diagnosis. Conclusions: Preterm infants exposed to a type of cow's milk-based formula in their first days of life have a higher risk of developing CMPA. Most of the preterm infants are no longer fed with human milk after the diagnosis of CMPA is made, which is in contrast with current nutrition guidelines in preterm infants. We strongly advocate that human milk with mothers on a cow's milk-free diet is the first choice of feed after the diagnosis of CMPA. Prospective studies are necessary to obtain more information regarding clinical presentation, diagnostic tools, and therapeutic approaches.

A different starting line for allergic march: food protein-induced allergic proctocolitis.

OBJECTIVE: The aim of this study is to investigate the long-term prognosis of food protein--induced allergic proctocolitis (FPIAP) patients, the risk of developing both allergic and gastrointestinal diseases, and to evaluate whether it leads to allergic march. METHODS: A total of 149 children who were diagnosed with FPIAP and developed tolerance at least 5 years prior to the study and 41 children (with no history of food allergy) as a control group were enrolled. Both groups were re-evaluated for allergic diseases as well as gastrointestinal disorders. RESULTS: The mean age of diagnosis for the FPIAP group was 4.2 ± 3.0 months, while the mean age of tolerance was 13.9 ± 7.7 months. The mean age of both FPIAP and control groups at the last visit was 101.6 ± 24.4 and 96.3 ± 24.1 months, respectively (P = 0.213). At the final evaluation of both groups, the comorbid allergic disease was significantly higher in the FPIAP group (P < 0.001). There was no significant difference between the two groups in terms of functional gastrointestinal disorders (FGIDs), eosinophilic gastrointestinal diseases, and inflammatory bowel disease (P = 0.198, 0.579, and 0.579, respectively).In the FPIAP group, the allergic disease was significantly higher at the final visit in patients with comorbid allergic disease at diagnosis (P < 0.001). In the FPIAP group, FGID was significantly higher in the group that developed allergic diseases in the future, compared to the group that did not develop allergic diseases in the future (P = 0.034). The proportion of both FGID and allergic diseases was significantly higher in subjects that developed tolerance at >18 months, compared to subjects that developed tolerance at >18 months (P < 0.001 and <0.001, respectively). CONCLUSIONS: Patients with FPIAP may develop allergic diseases as well as FGID in the long term.

Outcomes reported in randomized controlled trials for mixed and non-IgE-mediated food allergy: Systematic review.

BACKGROUND: Mixed and non-IgE-mediated food allergy is a subset of immune-mediated adverse food reactions that can impose a major burden on the quality of life of affected patients and their families. Clinical trials to study these diseases are reliant upon consistent and valid outcome measures that are relevant to both patients and clinicians, but the degree to which such stringent outcome reporting takes place is poorly studied. OBJECTIVE: As part of the Core Outcome Measures for Food Allergy (COMFA) project, we identified outcomes reported in randomized clinical trials (RCT) of treatments for mixed or non-IgE-mediated food allergy. DESIGN: In this systematic review, we searched the Ovid, MEDLINE and Embase databases for RCTs in children or adults investigating treatments for food protein-induced enterocolitis syndrome, food protein-induced allergic proctocolitis, food protein-induced enteropathy and eosinophilic gastrointestinal disorders including eosinophilic esophagitis [EoE], eosinophilic gastritis and eosinophilic colitis published until 14 October 2022. RESULTS: Twenty-six eligible studies were identified, with 23 focused on EoE (88%). Most interventions were corticosteroids or monoclonal antibodies. All EoE studies assessed patient-reported dysphagia, usually using a non-validated questionnaire. Twenty-two of 23 EoE studies used peak tissue eosinophil count as the primary outcome, usually using a non-validated assessment method, and other immunological markers were only exploratory. Thirteen (57%) EoE studies reported endoscopic outcomes of which six used a validated scoring tool recently recommended as a core outcome for EoE trials. Funding source was not obviously associated with likelihood of an RCT reporting mechanistic versus patient-reported outcomes. Only 3 (12%) RCTs concerned forms of food allergy other than EoE, and they reported on fecal immunological markers and patient-reported outcomes. CONCLUSIONS: Outcomes measured in clinical trials of EoE and non-IgE-mediated food allergy are heterogeneous and largely non-validated. Core outcomes for EoE have been developed and need to be used in future trials. For other forms of mixed or non-IgE-mediated food allergies, core outcome development is needed to support the development of effective treatments. SYSTEMATIC REVIEW REGISTRATION: OSF public registry DOI:10.17605/OSF.IO/AZX8S.

Dietary Factors May Delay Tolerance Acquisition in Food Protein-Induced Allergic Proctocolitis.

BACKGROUND: Dietary and environmental factors may influence tolerance acquisition in food protein-induced allergic proctocolitis (FPIAP). This retrospective observational study explored the role of maternal diet during pregnancy and breastfeeding in tolerance acquisition in infantile FPIAP. METHODS: Breastfed infants with FPIAP from six diverse regions in Greece were divided into two groups, based on development of tolerance to the trigger food: Group A (n = 43), before, and Group B (n = 53), after, the 6th month of age. Maternal diet during pregnancy and breastfeeding was elicited using the Mediterranean Diet Score Questionnaire and the Mediterranean Oriented Culture Specific Semi-Quantitative Food Frequency Questionnaire. RESULTS: Mean age at diagnosis of FPIAP (1.5 months) and weaning (5.5 months) were the same in both groups. The main trigger was cow's milk. Group A received infant milk formula earlier than Group B. Group B had a higher incidence of asthma/wheeze, siblings with milk allergy, maternal smoking and rural residence. On multivariate analysis, earlier resolution of FPIAP was associated with higher maternal education and with salt intake and consumption of goat/sheep cheese during pregnancy and olive oil during breastfeeding. Consumption of multivitamins during pregnancy and meat, winter fruits, green vegetables, butter, salt, "ready-to-eat" meals and pastries during breastfeeding were correlated with longer duration of symptoms. CONCLUSIONS: Mothers of children with FPIAP to cow's milk protein can be advised to eat more yogurt, cheese and olive oil during subsequent pregnancies, and avoid multivitamins, grilled food, "ready-to-eat" meals, pastries, meat and alcohol during breastfeeding, to reduce the duration of FPIAP presenting in future infants.

A different starting line for allergic march: food protein-induced allergic proctocolitis

Objective: The aim of this study is to investigate the long-term prognosis of food protein--induced allergic proctocolitis (FPIAP) patients, the risk of developing both allergic and gastrointestinal diseases, and to evaluate whether it leads to allergic march. Methods: A total of 149 children who were diagnosed with FPIAP and developed tolerance at least 5 years prior to the study and 41 children (with no history of food allergy) as a control group were enrolled. Both groups were re-evaluated for allergic diseases as well as gastrointestinal disorders. Results: The mean age of diagnosis for the FPIAP group was 4.2 ± 3.0 months, while the mean age of tolerance was 13.9 ± 7.7 months. The mean age of both FPIAP and control groups at the last visit was 101.6 ± 24.4 and 96.3 ± 24.1 months, respectively (P = 0.213). At the final evaluation of both groups, the comorbid allergic disease was significantly higher in the FPIAP group (P < 0.001). There was no significant difference between the two groups in terms of functional gastrointestinal disorders (FGIDs), eosinophilic gastrointestinal diseases, and inflammatory bowel disease (P = 0.198, 0.579, and 0.579, respectively). In the FPIAP group, the allergic disease was significantly higher at the final visit in patients with comorbid allergic disease at diagnosis (P < 0.001). In the FPIAP group, FGID was significantly higher in the group that developed allergic diseases in the future, compared to the group that did not develop allergic diseases in the future (P = 0.034). The proportion of both FGID and allergic diseases was significantly higher in subjects that developed tolerance at >18 months, compared to subjects that developed tolerance at >18 months (P < 0.001 and <0.001, respectively). Conclusions: Patients with FPIAP may develop allergic diseases as well as FGID in the long term (AU)

Food Protein-Induced Allergic Proctocolitis: The Effect of Maternal Diet During Pregnancy and Breastfeeding in a Mediterranean Population.

Background: The aim of the current investigation was to explore the association of food protein-induced allergic proctocolitis (FPIAP) with the maternal diet during pregnancy and breastfeeding in Greek infants. Methods: A multicenter retrospective case-control study was conducted in 6 regions in Greece, with 96 mothers of infants with and 141 mothers of infants without a history of FPIAP. Maternal dietary habits during pregnancy and breastfeeding were evaluated with the following validated questionnaires: (a) The Mediterranean Diet Score and (b) The Mediterranean Oriented Culture-Specific Semi-Quantitative Food Frequency Questionnaire. Results: FPIAP was associated with cow's milk (83.6%), egg (7.3%), wheat (6.4%), and beef (6.4%) in the maternal diet. Adherence to Mediterranean Diet was similar among the mothers. Mothers of FPIAP infants consumed more vegetables. Elastic net prediction models showed that, in this Mediterranean population, increased consumption during pregnancy and lactation of common allergens, whole grain products, homemade food, fish and shellfish, and fruits was associated with a decreased risk of FPIAP. Conversely, a high intake of vegetables, sugar and total fat, and non-stick/grilled cooking, were associated with increased risk of FPIAP, as was a high intake of salt and white flour during lactation only. Conclusions: Components of a maternal Mediterranean Diet may protect against FPIAP when traditional cooking methods are adopted and fish, fruit, and whole wheat products are consumed frequently during pregnancy and breastfeeding.

Clinical Features and Clinical Course of Food Protein-Induced Allergic Proctocolitis: 10-Year Experience of a Tertiary Medical Center.

BACKGROUND: Food protein-induced allergic proctocolitis (FPIAP) is a food allergy characterized by bloody stools in well-appearing breast-fed infants. OBJECTIVE: To determine the clinical course of FPIAP and the factors affecting the development of tolerance. METHODS: Over a 10-year period, patients with a diagnosis of FPIAP who were followed at the outpatient Allergy-Immunology clinic in a tertiary care children's hospital in Turkey were retrospectively analyzed. RESULTS: The frequency of FPIAP was 0.18% among 64,549 patients. The median age of symptom onset was 2 months (interquartile range, 1.0-3.5 months), and the median age of tolerance development was 12 months (interquartile range, 8.0-17.21 months). The occurrence of symptoms in the neonatal period was associated with a history of premature birth (odds ratio, 3.75; 95% CI, 1.33-10.59; P = .031) and neonatal intensive care unit hospitalization (odds ratio, 4.72; 95% CI, 1.78-12.53; P = .002). Use of a cow's milk-based formula was associated with a higher risk of the onset of symptoms after 1 month (odds ratio, 2.69; 95% CI, 1.19-6.07; P = .016). The use of an amino acid-based formula and the presence of diarrhea at admission were associated with later development of tolerance (P = .023 and P < .001, respectively). An IgE-mediated reaction was observed during oral food challenge testing in 6% of the patients. CONCLUSIONS: The manifestations of FPIAP appeared earlier in premature infants and later in infants using formula. The use of amino acid-based formula and having had diarrhea were associated with delayed tolerance.

Newborns with Bloody Stools-At the Crossroad between Efficient Management of Necrotizing Enterocolitis and Antibiotic Stewardship.

The onset of bloody stools in neonates often results in antibiotic treatment for suspected necrotizing enterocolitis (NEC). Food protein-induced allergic proctocolitis (FPIAP) is an often-neglected differential diagnosis. We performed a retrospective analysis of antibiotic exposure at our tertiary center from 2011 to 2020 that included three time periods of differing antimicrobial stewardship goals. We compared these data with the conventional treatment guidelines (modified Bell's criteria). In our cohort of 102 neonates with bloody stools, the length of antibiotic exposure was significantly reduced from a median of 4 to 2 days. The proportion of treated neonates decreased from 100% to 55% without an increase in negative outcomes. There were 434 antibiotic days. Following a management strategy according to modified Bell's criteria would have led to at least 780 antibiotic days. The delayed initiation of antibiotic treatment was observed in 7 of 102 cases (6.9%). No proven NEC case was missed. Mortality was 3.9%. In conclusion, with FPIAP as a differential diagnosis of NEC, an observational management strategy in neonates with bloody stools that present in a good clinical condition seems to be justified. This may lead to a significant reduction of antibiotic exposure. Further prospective, randomized trials are needed to prove the safety of this observational approach.

Non-IgE-Mediated Gastrointestinal Food Protein-Induced Allergic Disorders. Clinical Perspectives and Analytical Approaches.

Non-IgE-mediated gastrointestinal food allergy (non-IgE-GI-FA) is the name given to a series of pathologies whose main entities are food protein-induced allergic proctocolitis (FPIAP), food protein-induced enteropathy (FPE), and food protein-induced enterocolitis syndrome (FPIES). These are more uncommon than IgE-mediated food allergies, their mechanisms remain largely unknown, and their diagnosis is mainly done by clinical history, due to the lack of specific biomarkers. In this review, we present the latest advances found in the literature about clinical aspects, the current diagnosis, and treatment options of non-IgE-GI-FAs. We discuss the use of animal models, the analysis of gut microbiota, omics techniques, and fecal proteins with a focus on understanding the pathophysiological mechanisms of these pathologies and obtaining possible diagnostic and/or prognostic biomarkers. Finally, we discuss the unmet needs that researchers should tackle to advance in the knowledge of these barely explored pathologies.

Non-IgE-mediated food allergy: Evaluation and management.

The most common types of non-IgE-mediated food allergy are food protein-induced enterocolitis syndrome (FPIES) and food protein-induced allergic proctocolitis (FPIAP). FPIES presents with delayed refractory emesis, while FPIAP presents with hematochezia in otherwise healthy infants. Acute management of FPIES includes rehydration or ondansetron, or both. No acute management is required for FPIAP. Long-term management of both disorders includes avoidance of the trigger food. The prognosis for both conditions is a high rate of resolution within a few years' time.

Portal vein thrombosis and food protein-induced allergic proctocolitis in a premature newborn with hypereosinophilia: a case report.

BACKGROUND: Peripheral blood eosinophilia is identified in numerous medical conditions associated with allergic, infectious, and inflammatory processes mostly as reactive eosinophilia with or without tissue eosinophilia. In hospitalized neonates, eosinophilia is common with an inverse relationship with gestational age and occurs solely as mild eosinophilia in the majority of cases. In the literature, eosinophilia has been proposed as a possible risk factor for venous thromboembolism. However, few reports are found on thromboembolic events including portal vein thrombosis (PVT) associated with eosinophilia in the newborn period. Neonates, particularly preterm infants, are vulnerable to thrombosis due to the immature and developing hemostatic system with little reserve capacity, which occurs as catheter-related thrombosis in most cases. CASE PRESENTATION: A male newborn at 34+ 5 weeks' gestation presented with a left portal venous thrombus and hematochezia after initial cow's milk feeding in the setting of blood hypereosinophilia for a prolonged period of time without central venous catheterization. The infant was diagnosed with PVT and food protein-induced allergic proctocolitis (FPIAP) and showed complete resolution of the conditions with expectant management with food avoidance, including the normalized eosinophil count. CONCLUSIONS: Our experience suggests that in the setting of hypereosinophilia with a prolonged duration in premature neonates, FPIAP should be suspected in case of hematochezia in otherwise healthy infants, and considering the increased thrombotic risk by the hypereosinophilia and premature newborn status, evaluation for neonatal thrombosis may be needed, including PVT with the potential risk for the more serious, but uncommon, late complications encompassing portal hypertension.

Pathophysiology of Non-IgE-Mediated Food Allergy.

Non-IgE-mediated food allergies are a group of disorders characterized by subacute or chronic inflammatory processes in the gut. Unlike IgE mediated food allergies that may result in multi-organ system anaphylaxis, the non-IgE mediated food allergies primarily affect the gastrointestinal tract. This review outlines the clinical manifestations, epidemiology, pathophysiology, and management of non-IgE-mediated food allergies. An updated literature search of selected non-IgE-mediated food allergies was conducted for this review using PubMed database to the current year (2021). Reviewed disorders include food protein-induced enterocolitis syndrome (FPIES), food-protein enteropathy (FPE), food protein-induced allergic proctocolitis (FPIAP), and eosinophilic gastrointestinal disorders (EGIDs) such as eosinophilic esophagitis (EoE). While extensive gains have been made in understanding FPIES, FPIAP, FPE, and EoE, more information is needed on the pathophysiology of these food allergies. Similarities among them include involvement of innate immunity, T-lymphocyte processes, alteration of the intestinal lumen at the cellular level with the appearance of inflammatory cells and associated histologic changes, and specific cytokine profiles suggesting food-specific, T-cell, and immune-mediated responses. While FPIES and FPIAP typically resolve in early childhood, EGIDs typically do not. Emerging new therapies for EoE offer promise of additional treatment options. Further studies identifying the immunopathogenesis, associated biomarkers, and mechanisms of tolerance are needed to inform prevention, diagnosis and management.

Outcomes of Infants With Severe Refractory Food Protein-induced Allergic Proctocolitis Treated With Mesalamine.

This retrospective chart review evaluates the outcomes of mesalamine treatment in infants with severe food protein-induced allergic proctocolitis (FPIAP) and persistent clinical symptoms despite the use of elemental formulas. Patients received mesalamine in a 40-60 mg/kg/d dose for an average of 100 days. This group showed significantly higher rates of improvement in the most common symptoms of FPIAP compared with the control group. In addition, the mesalamine group was less likely to need pharmacological treatment for gastroesophageal reflux disease and more likely to successfully transition to whole milk or soy milk after 1 year of age. In conclusion, using mesalamine can be a useful addition to the treatment of severe refractory cases of FPIAP.

Prospective Assessment of Pediatrician-Diagnosed Food Protein-Induced Allergic Proctocolitis by Gross or Occult Blood.

BACKGROUND: Food protein-induced allergic proctocolitis (FPIAP) is an early and common manifestation of food allergy, yet its epidemiology and relationship to other allergic diseases remain unclear. OBJECTIVE: To prospectively define the incidence of FPIAP as it is being diagnosed clinically in the community and to identify factors associated with its development. METHODS: A total of 1003 of 1162 eligible serial healthy newborn infants recruited from a single suburban pediatrics practice were followed prospectively for the diagnosis of FPIAP. Investigators reviewed each case to confirm prespecified inclusion criteria, including documented gross or occult blood in the stool. RESULTS: A total of 903 infants were analyzed (46% females, 89% term, 32% caesarian-section, 9% neonatal antibiotics); 153 cases met inclusion criteria, a cumulative incidence of 17%, while 63 (7%) had gross blood. Infants initially fed both breast milk and formula were 61% less likely to develop FPIAP compared with those exclusively formula-fed (hazard ratio, 0.39; P = .005). Breast milk and formula at any point during the first 4 months were also associated with lower risk compared with exclusive formula or exclusive breast milk (hazard ratio, 0.44; P = .005; hazard ratio, 0.62; P = .0497). Eczema (odds ratio, 1.5; 95% confidence interval, 1.1- 2.2; P = .02) or a first-degree relative with food allergies (odds ratio, 1.9; 95% confidence interval, 1.2-2.8; P = .005) were among risk factors for FPIAP development. CONCLUSIONS: The prospectively defined incidence of FPIAP when diagnosed clinically by community pediatricians without challenge is markedly higher than published estimates. Combination feeding of formula and breast milk is associated with the lowest rate of FPIAP in this population.

Non-IgE-mediated Adverse Food Reactions.

PURPOSE OF REVIEW: The purpose of this review is to update what is currently known about the major non-IgE-mediated food allergies: food protein-induced enterocolitis syndrome (FPIES), food protein-induced allergic proctocolitis (FPIAP), and food protein-induced enteropathy (FPE). These conditions are similar in that symptoms are regulated to the gastrointestinal tract; therefore understanding their specific features is important for diagnosis and management. RECENT FINDINGS: The most progress has been made in understanding FPIES with several recent large cohorts being described. The first international consensus guidelines for FPIES were published in 2017 and propose specific diagnostic criteria for acute FPIES as well as guidance for diagnosing chronic FPIES. Recent studies in FPIAP have challenged our thinking about the recommended duration of food avoidance and that cow's milk avoidance is the primary management with reports of self-resolution without dietary management. FPE continues to appear to be on the decline. FPIES, FPIAP, and FPE are distinguished from one another by their main clinical features: delayed repetitive vomiting in FPIES, benign blood in stool in FPIAP, and chronic diarrhea in FPE. Due to the risk of nutritional deficiencies with food avoidance in both infant and maternal diets if breastfeeding, confirmation of diagnosis with challenges is encouraged. Additional studies are needed for these conditions to elucidate pathophysiology, search for diagnostic markers, and understand natural history.

Tolerance development in food protein-induced allergic proctocolitis: Single centre experience.

BACKGROUND: Food protein-induced allergic proctocolitis (FPIAP) is characterised by inflammation of the distal colon in response to one or more food proteins. It is a benign condition of bloody stools in a well-appearing infant, with usual onset between one and four weeks of age. OBJECTIVE: Our objective was to examine the clinical properties of patients with FPIAP, tolerance development time as well as the risk factors that affect tolerance development. METHODS: The clinical symptoms, offending factors, laboratory findings, methods used in the diagnosis and tolerance development for 77 patients followed in the Paediatric Allergy and Gastroenterology Clinics with the diagnosis of FPIAP during January 2010-January 2015 were examined in our retrospective cross-sectional study. RESULTS: The starting age of the symptoms was 3.3±4.7 months (0-36). Milk was found as the offending substance for 78% of the patients, milk and egg for 13% and egg for 5%. Mean tolerance development time of the patients was 14.7±11.9 months (3-66 months). Tolerance developed before the age of one year in 40% of the patients. Tolerance developed between the age of 1-2 years in 27%, between the age of 2-3 years in 9% and after the age of 3 years in 5% of the patients. CONCLUSIONS: Smaller onset age and onset of symptoms during breastfeeding were found associated with early tolerance development. In the majority of the patients, FPIAP resolves before the age of one year, however in some of the patients this duration may be much longer.

Non-IgE-mediated gastrointestinal food allergies in children.

Non-IgE-mediated gastrointestinal food allergic disorders (non-IgE-GI-FA) including food protein-induced enterocolitis syndrome (FPIES), food protein-induced enteropathy (FPE), and food protein-induced allergic proctocolitis (FPIAP) are relatively uncommon in infants and young children, but are likely under-diagnosed. Non-IgE-GI-FA have a favorable prognosis, with majority resolving by age 3-5 years. Diagnosis relies on the recognition of symptoms pattern in FPIAP and FPIES and biopsy in FPE. Further studies are needed for a better understanding of the pathomechanism, which will lead eventually to the development of diagnostic tests and treatments. Limited evidence supports the role of food allergens in subsets of constipation, gastroesophageal reflux disease, irritable bowel syndrome, and colic. The immunologic pathomechanism is not fully understood and empiric prolonged avoidance of food allergens should be limited to minimize nutrient deficiency and feeding disorders/food aversions in infants.