Shift from Cow's Milk Food Protein-Induced Enterocolitis Syndrome to IgE-Mediated Allergy: Case Series and Literature Review.

Background: Food protein-induced enterocolitis syndrome (FPIES) is a non-IgE-mediated food allergy characterized by gastrointestinal symptom onset within 1-4 hours from trigger food ingestion. In the literature, some authors have previously described the possibility that a patient with FPIES may develop an IgE-mediated allergy to the same trigger food, especially cow's milk (CM). Case Presentation: We reported five cases of CM-FPIES converting to IgE-mediated CM allergy presented at our tertiary pediatric Allergy Unit and performed a review of the literature, aiming to characterize the clinical features of patients who are at risk of developing such conversion. Conclusions: This phenomenon raises the question of whether IgE-mediated and non-IgE-mediated allergies represent a spectrum of the same disease and highlights the need for further investigation to understand the pathophysiological mechanisms of this process.

Efficacy of sequential fecal-marker examination for evaluating gastrointestinal inflammation in solid food protein-induced enterocolitis syndrome.

BACKGROUND: Food protein-induced enterocolitis syndrome caused by solid foods (Solid-FPIES) is a non-immunoglobulin E-mediated allergic disease characterized by delayed gastrointestinal symptoms. An oral food challenge (OFC) test, although necessary, can be inconclusive in cases with mild symptoms. Moreover, limited diagnostic marker availability highlights the need for novel surrogate markers. We aimed to examine the efficacy of fecal hemoglobin (FHb), lactoferrin (FLf), and calprotectin (FCp) over time in evaluating gastrointestinal inflammation degree in Solid-FPIES. METHODS: This observational study included 40 patients and 42 episodes at Juntendo University Hospital and affiliated hospitals between October 2020 and March 2024 categorized into FPIES (12 patients with 11 egg yolk, 1 fish, and 1 soybean episodes), control (14 patients with 15 episodes), and remission (14 patients). Fecal tests were performed for 7 days following antigen exposure. The ratios of each value were divided by the baseline value and analyzed over time course. RESULTS: The FPIES group had significantly higher peak ratios of all fecal markers than the control group (p < 0.01). The median FHb, FLf, and FCp ratios were 3.25, 9.09, and 9.79 in the FPIES group and 1.08, 1.29, and 1.49 in the control group, respectively. In the remission group, several patients had fluctuating fecal markers despite negative OFC, and one patient was diagnosed with FPIES by OFC with increased load. Receiver operating characteristic curve analyses revealed high diagnostic performance for each fecal marker in FPIES. CONCLUSIONS: Sequential fecal marker examination proved valuable in diagnosing Solid-FPIES and evaluating the degree of gastrointestinal inflammation.

Clinical-haematological changes and predictors of severity in acute food protein-induced enterocolitis syndrome reactions at oral food challenge: a multicentre observational study.

BACKGROUND: Oral food challenge (OFC) is the gold standard for diagnosis of acute Food Protein-Induced Enterocolitis Syndrome (FPIES). No diagnostic/prognostic biomarkers are available, and OFC assessment criteria are not validated. OBJECTIVE: To assess clinical-haematological changes and predictors of severity of FPIES reactions at OFC. METHODS: Observational multicentre prospective study. Children aged 0-18 years diagnosed with acute FPIES were recruited at follow-up OFC in 12 tertiary centres in Spain and Italy. OFC Outcomes (as positive/negative/inconclusive and mild/moderate/severe) were assessed based on published '2017 FPIES Consensus' criteria. Clinical characteristics were recorded, and full blood count was done at baseline, reaction onset and 4 hours later. Regression analysis was performed to assess predictors of severe reactions at OFC. RESULTS: 81 children had positive OFC (mild in 11% (9/81), moderate in 61% (49/81), severe in 28% (23/81)). Increase in neutrophils and reduction in eosinophils, basophils and lymphocytes was observed (P-value<0.05). OFC was inconclusive in 19 cases despite objective signs or neutrophilia. Regression analysis showed a 2-day OFC protocol where only 25% of an age-appropriate portion is given on day 1 (not gender, age, culprit food, cumulative dose and previous reaction severity) was associated with reduced odds of severe reaction compared to giving multiple doses in a single day. CONCLUSION: Distinct haematological changes may help support FPIES diagnosis. Current OFC assessment criteria may not capture the broad spectrum of acute FPIES presentations. This 2-day protocol may associate a reduced risk of severe reactions. Future work should aim to develop safer OFC and non-OFC diagnostics for FPIES.

A Second Slice of FPIES: A Single-Center Reappraisal of Pediatric FPIES.

BACKGROUND: Food protein-induced enterocolitis syndrome (FPIES) is being increasingly recognized as a non-IgE-mediated food allergy; however, it remains unclear if and how the presentation, diagnosis, and management of this disease has changed in recent years. OBJECTIVE: To reappraise the FPIES cohort at a large US pediatric tertiary referral center. METHODS: We performed a retrospective chart review of pediatric patients with FPIES (International Classification of Diseases, Tenth Revision code K52.21) diagnosed in our allergy/immunology clinics between 2018 and 2022. RESULTS: There were 210 children diagnosed with FPIES. Most were White (73.8%), non-Hispanic (71.4%), and male (54.3%) with private insurance (77.6%). Cow's milk was the most common food trigger (35.2%), with the earliest median age of onset of 5 months. The atypical FPIES rate was 13.8%. FPIES was accurately diagnosed in 54.3% at the first medical contact. The oral food challenge pass rate was 73.5%. The rate of trigger resolution at 36 months was 77%. CONCLUSIONS: By comparing trends from a previous and current FPIES cohort, we were able to assess the potential impact of various guidelines and practice changes on the diagnosis and management of FPIES at our center. Milk and oat surpassed rice as the most common FPIES triggers; peanut and egg emerged as new FPIES triggers; there was a shorter time to diagnosis and an increased rate of atypical FPIES. Our findings reflect earlier recognition of FPIES and prompt allergy/immunology referral from community physicians, implementation of recent medical society guidelines for infant feeding practices, and growing clinical expertise of allergists at our center.

Wheat-Triggered Food Protein-Induced Enterocolitis Syndrome in Celiac Children on Gluten-Free Diet: A New Clinical Association.

INTRODUCTION: The association between food protein-induced enterocolitis syndrome (FPIES) and wheat ingestion in children with celiac disease is unknown at this time. METHODS: We present seven cases of children with celiac disease who presented with symptoms of wheat-triggered acute FPIES (a-FPIES). An oral food challenge (OFC) with wheat allergen followed by 4 h of observation was performed. Activation of innate system cells was measured at baseline (T0), during symptoms (Ts), and 4 h after symptom onset (Ts + 4). A panel of human inflammatory cytokines was also performed. RESULTS: All patients reacted to the first allergen dose. Three patients experienced a decrease of 30 mm Hg in systolic blood pressure and tachycardia and required hemodynamic resuscitation. Neutrophilia and a decrease in eosinophil count were evident at 4 h after symptom onset. At 4 h after symptom onset, cytokines (IL-6 and IL-8, and to a lesser degree, IL-10) were elevated. CONCLUSION: In a small sample of celiac patients with wheat exposure in an OFC, symptoms and acute immunological changes in serum inflammatory cytokine profile were consistent with a-FPIES.

Resolution of Food Protein-Induced Enterocolitis Syndrome-A Long-Term Follow-Up Study of 113 Swedish Children.

BACKGROUND: Food protein-induced enterocolitis syndrome (FPIES), a non-IgE-mediated allergy, primarily affects infants and young children. Whether and when tolerance develops seems to vary among populations and trigger foods. OBJECTIVE: This study aimed to evaluate tolerance development and its assessment in a Swedish cohort. METHODS: This was a prospective follow-up study of a Swedish cohort of 113 children, followed at 25 pediatric departments, with acute FPIES. Data on oral food challenges and FPIES resolution were collected through chart reviews and, if incomplete, supplemental caregiver interviews. RESULTS: The median age at last follow-up was 5.6 years (range: 8.7 months to 16.5 years). Eighty-three children (73%) developed tolerance to 96 of 137 (70%) foods: 93% for cow's milk, 92% for oat, and 46% for fish. The median age when tolerance was developed was 36.0 months (interquartile range: 23.7-48.2 months): 24.4 months for cow's milk, 30.1 months for oat, and 49.4 months for fish. Tolerance was determined in hospital in 45% of cases. Five percent demonstrated allergic sensitization to their FPIES trigger food. Age at tolerance development did not differ between sensitized and nonsensitized patients. CONCLUSIONS: Most of the children in this Swedish cohort with FPIES achieved tolerance before age 4 years. Cow's milk- and oat-induced FPIES had similar remission patterns, with early resolution. Development of tolerance to fish occurred significantly later compared with all other FPIES-inducing foods.

Heterogeneity of food protein-induced enterocolitis syndrome (FPIES).

Food protein-induced enterocolitis syndrome (FPIES) is a non-IgE-mediated food allergy with gastrointestinal symptoms such as vomiting and diarrhea. The development of international consensus guidelines for the diagnosis and management of FPIES in 2017 enabled us to compare patients worldwide, regardless of geographic variation in disease features. As a result, it has become clear that there is heterogeneity among patients with FPIES or that there are cases that partly fit the diagnostic criteria for FPIES but have different characteristics. This review highlights the heterogeneity in FPIES characteristics in terms of trigger foods, the age of onset, differences in geographic regions, and symptoms; it further proposes four disease entities, including acute FPIES in children, acute FPIES in adults, chronic FPIES, and early-onset neonatal FPIES, depending on the age of onset and presumed pathophysiology. The major symptoms at onset and trigger foods differ in acute FPIES in children, acute FPIES in adults, and chronic FPIES, whereas the disease entities may share a similar pathophysiology. Early-onset neonatal FPIES may have a different pathophysiology than acute or chronic FPIES, and may not necessarily fulfil the full diagnostic criteria for acute or chronic FPIES described in the international consensus guidelines. Due to the similarity in symptoms, early-onset neonatal FPIES may sometimes be misdiagnosed as necrotizing enterocolitis. We aim to increase awareness of FPIES among medical staff in pediatrics, neonatology, and internal medicine and promote research, to gain a better understanding of the heterogeneity and pathophysiology of FPIES.

Differences in Characteristics Between Patients Who Met or Partly Met the Diagnostic Criteria for Food Protein-Induced Enterocolitis Syndrome (FPIES).

BACKGROUND: Some patients with food protein-induced enterocolitis (FPIES)-like allergy do not completely fulfill the diagnostic criteria of the international consensus guideline for FPIES. However, it is unclear whether such FPIES-like patients represent a completely different population from FPIES. OBJECTIVE: This study aimed to clarify differences in characteristics between patients with FPIES who fully met diagnostic criteria and those who partly met them. METHODS: This was a cross-sectional study using data at the time of registration in multicenter, prospective studies of patients with FPIES in Japan. Children who had delayed emesis within 1 to 4 hours and/or diarrhea within 5 to 10 hours after ingestion of food were recruited between March 2020 and February 2022. We examined their compatibility with the diagnostic criteria of the international consensus guideline and their detailed clinical characteristics, including trigger foods, the serving size that elicited symptoms, and antigen-specific IgE antibody titers. RESULTS: Of the 225 patients with FPIES, 140 fully met the diagnostic criteria whereas 79 patients did not fully meet them but demonstrated reproducible symptoms. The frequencies of pallor, lethargy, and diarrhea were significantly higher in those who met the criteria fully, whereas the age at onset, trigger foods, comorbidity, and perinatal information were comparable. Analysis of patients with FPIES to hen's egg revealed significantly higher levels of egg white- and egg yolk-specific IgE in patients who partly met criteria, whereas the serving size eliciting symptoms was comparable. CONCLUSIONS: Patients who partly met the diagnostic criteria may have a milder phenotype of FPIES, but this needs to be validated in further studies using biomarkers reflecting the pathophysiology.

Effectiveness of continuous allergenic food intake for acute food protein-induced enterocolitis syndrome.

Continuous intake of allergenic food is a safe and efficient treatment strategy for patients with a prolonged course of acute food protein-induced enterocolitis syndrome. The initial dose, dose escalation rate, and starting age for continuous allergenic food intake need further clarification.

Delayed presentation of food protein-induced enterocolitis syndrome (FPIES) to okra in a toddler.

BACKGROUND: Food protein-induced enterocolitis syndrome (FPIES) is a non-immunoglobulin E (IgE) -mediated food allergy predominantly observed in infants and characterized by the delayed onset of vomiting following ingestion of a trigger food. An increase in research and clinical consideration of FPIES has led to the discovery of unique deviations from the standard FPIES triggers and presentations. CASE PRESENTATION: A 34-month-old female patient with a history of consuming okra daily presented to medical attention after developing classic FPIES symptoms to okra beginning at 14-months of age. CONCLUSIONS: Recently, awareness about the varied nature of FPIES clinical presentation has come to light. This case is the first to describe FPIES to the fruit okra that developed over a 12-month time span after previously tolerating the food. This case serves to emphasize the importance of understanding the range of FPIES symptoms to improve recognition and expedite best practice recommendations.

Epidemiology and the Growing Epidemic of Food Allergy in Children and Adults Across the Globe.

PURPOSE OF REVIEW: Food allergies are immune-mediated, complex disorders, which are the source of increasing health concern worldwide. The goal of this review is to present an updated summary of the food allergy (FA) burden among children and adults across different populations, focusing on research from the past 5 years. RECENT FINDINGS: FAs impact a growing number of global residents-particularly those residing in higher-income, industrialized regions. Moreover, growing epidemiologic evidence suggests that the population health burden of non-IgE-mediated FAs, such as food protein-induced enterocolitis syndrome, may also be higher than previously reported. FA is a complex trait that impacts infants, children, as well as adults across the globe. The population health burden of both IgE- and non-IgE-mediated FAs is likely to grow in the absence of rapid advances and widespread implementation of effective FA prevention and treatment interventions. Systematic epidemiological research initiatives are needed, both nationally and globally, to better understand and reduce the burden of these allergic diseases.

Discrepancy between Caregivers' Reports and Physicians' Evaluation of Causative Foods in Food Protein-Induced Enterocolitis Syndrome in Japan: The Japan Environment and Children's Study.

INTRODUCTION: Food protein-induced enterocolitis syndrome (FPIES) is a form of non-IgE-mediated gastrointestinal food allergy. FPIES is considered a rare food allergy disorder and is often under-recognized. Therefore, clinicians should have a better understanding of its manifestations and maintain a high index of suspicion for a correct diagnosis. To this end, information about differences in the characteristics of caregiver-reported and physician-diagnosed FPIES is important. METHODS: The present, national, multicentric, prospective birth cohort study, called the Japan Environment and Children's Study (JECS), enrolled a general population of 104,062 fetal records. The characteristics of FPIES in 1.5-year-old children were categorized as cases reported by caregivers or as those diagnosed by a physician using questionnaire data. RESULTS: The prevalence of caregiver-reported and physician-diagnosed FPIES cases was 0.69% and 0.06%, respectively. Among the former, the most common causative food was hen's egg (HE), and the second most common causative food was cow's milk (CM) (51.0% and 17.1% of patients responded to HE and CM, which accounted for 46% and 15% of all the causative foods, respectively). Conversely, among the physician-diagnosed cases, the most common causative food was CM followed by HE (57.7% and 36.5% of patients responded to CM and HE, which accounted for 46% and 29% of all the causative foods, respectively). CM accounted for a significantly higher proportion of causative foods in physician-diagnosed FPIES while HE accounted for a significantly higher proportion of caregiver-reported FPIES (p < 0.05). CONCLUSION: A discrepancy was found in reports of the most common causative food between caregiver-reported and physician-diagnosed cases of FPIES.

Personalization of Complementary Feeding in Children With Acute Food Protein-Induced Enterocolitis Syndrome.

Food protein-induced enterocolitis syndrome (FPIES) is a food allergy that results in repetitive vomiting, lethargy, and pallor within 1 to 4 hours of food ingestion. One of the issues in its management is the introduction of new foods. Over the past 25 years, suggestions have been made mainly based on the likelihood that a given food family could induce an episode of acute FPIES. Thus, foods have been categorized into low, moderate, and high risk. The suggestion was always to postpone the introduction of moderate- or high-risk foods, leaving the decision whether to introduce them at home or in hospital to the doctor. These suggestions were designed for all children with acute FPIES, regardless of their geographical area. However, it is true that these suggestions are the result of expert opinion. In recent years, studies have been published that have shown that the risk category of foods varies according to geographical area and so does the prevalence of single FPIES versus multiple FPIES. For this reason, we believe that the introduction of new foods in the child with acute FPIES can and should be tailored according to the geographical area.

Cow's Milk Protein Allergy.

Cow's milk allergy refers to an immunological reaction to milk protein. It is one of the commonest food protein allergies with an estimated prevalence of 0.5% to 3% at 1 y of life. The disease may be IgE or non-IgE mediated or mixed with a wide range of symptoms often involving multiple organ systems. Gastrointestinal manifestations are common in non-IgE disease and may consist of enteropathy, proctocolitis, colic, reflux-like symptoms, constipation, enterocolitis syndrome and eosinophilic esophagitis. The gold standard for diagnosis remains a double-blind placebo-controlled oral challenge. Specific IgE and skin prick tests may predict severe and persistent disease, and aid in deciding on reintroduction or oral immunotherapy; however, they do not contribute to a definitive diagnosis as they indicate only sensitization. In practice, an elimination diet followed by open challenge under medical supervision is often used for diagnosis except when symptoms are severe such as anaphylaxis. Management consists of the elimination of the allergen with resolution of symptoms between 1-4 wk later depending on the type of allergy. Extensively hydrolyzed and Amino acid formulas are used to substitute milk in infants. Soy-based formulas are often utilized in resource-limited settings. Tolerance to the protein develops over time and periodic reintroduction should be attempted every six months after the initial one year of elimination diet. Oral immunotherapy is a newer treatment technique for IgE-mediated disease. There is no firm evidence on prevention apart from recommending breast feeding in early life along with initiating complementary feeding between 4-6 mo age.

Rates of New Peanut Allergy and Discontinuation Following Introduction in High-Risk Infants.

BACKGROUND: Peanut introduction guidelines recommend that infants with severe eczema and/or egg allergy consume 6 g of peanut protein weekly to prevent peanut allergy. Rates of new peanut allergy after introduction and adherence remain under study. OBJECTIVE: To determine compliance with peanut introduction guidelines, rates of new peanut allergy, and reasons for discontinuation of peanut consumption in a cohort of high-risk infants. METHODS: A prospective cohort of 4- to 11-month-old high-risk infants (defined as moderate-severe eczema or non-peanut food allergy or a first-degree relative with peanut allergy) with no prior peanut exposure who were determined to not be peanut allergic were recommended to introduce 6 g of peanut protein weekly. Participants were followed to 30 months with 2 in-person visits and monthly questionnaires. RESULTS: Two hundred seventy-seven infants were followed. At last follow-up, 245 (88%) were consuming some peanut protein with median weekly consumption of 3 g (interquartile range: 1-5 g). New peanut allergy developed in 6 (2%), with 2 of those cases consistent with food protein-induced enterocolitis syndrome. Fear of reaction in another household member was the most common reason for peanut discontinuation. Reactions to peanut after introduction in the index infant occurred in <2% of peanut-allergic siblings and in 20% of peanut-allergic parents. CONCLUSION: We found low rates of new peanut allergy and generally low rates of peanut discontinuation after introduction in our high-risk cohort. However, families of high-risk infants require significant support with introduction, especially those with another peanut-allergic member.

A detailed intake-status profiling of seafoods in adult food-protein-induced enterocolitis syndrome patients.

BACKGROUND: Adults with food-protein-induced enterocolitis syndrome (FPIES) often develop severe abdominal symptoms after eating seafood. However, no investigation of a food elimination strategy for adult FPIES patients has been performed to date. METHODS: We conducted a retrospective cohort study of seafood-avoidant adults by telephone interview, based on the diagnostic criteria for adult FPIES reported by González et al. We compared the clinical profiles, abdominal symptoms, and causative seafoods between FPIES and immediate-type food allergy (IgE-mediated FA) patients. We also profiled the detailed intake-status of seafoods in adult FPIES patients. RESULTS: Twenty-two (18.8 %) of 117 adults with seafood-allergy were diagnosed with FPIES. Compared with the IgE-mediated FA patients, FPIES patients had an older age of onset, more pre-existing gastrointestinal and atopic diseases, more episodes, longer latency and duration of symptoms, more nausea, abdominal distention, and severe abdominal pain, and more frequent vomiting and diarrhea. In particular, abdominal distention-reflecting intestinal edema and luminal fluid retention-may be the most distinctive characteristic symptom in adult FPIES (p < 0.001). Bivalves, especially oysters, were the most common cause of FPIES. Strikingly, intake-status profiling revealed that many FPIES patients can safely ingest an average of 92.6 % of seafood species other than the causative species. CONCLUSIONS: There are many differentiators between FPIES and IgE-mediated FA, which may reflect differences in the underlying immunological mechanisms. Although seafood FPIES is unlikely to induce tolerance, many patients can ingest a wide variety of seafood species after a long period from onset.

Food protein-induced enterocolitis syndrome is an important differential diagnosis of vomiting in pediatric emergency.

BACKGROUND: The aim of this study was to clarify the clinical characteristics and management of infants with suspected acute food protein-induced enterocolitis syndrome (FPIES) who presented to the pediatric emergency department (ED) before and after the guidelines were published. METHODS: This was a retrospective cohort study. We classified the infants as "acute FPIES-like symptoms" who were younger than 12 months of age and visited the pediatric ED of the National Center for Child Health and Development due to vomiting 1-4 h after food ingestion without any causative disease, such as infection. The medical records of those infants in 2015 and 2021 were reviewed. We used the nonparametric Mann-Whitney U test to compare two groups for continuous variables, whereas chi-squared or Fisher's exact tests were used for nominal variables. RESULTS: The number of infants with acute FPIES-like symptoms was 15 (13%) in 2015 and 14 (15%) in 2021. The trigger foods were cow's milk or dairy products in half of the infants, and five as a result of ingestion of hen's eggs in 2021, compared to zero cases in 2015. Five in 2015 and 12 in 2021 required examination at the ED. Three in 2015 and six in 2021 met the diagnostic criteria for acute FPIES in the international consensus guidelines. The emergency physicians did not record at least four minor criteria for acute FPIES in seven in 2015 and five in 2021. No infants (0%) in 2015 and two (14%) in 2021 were referred to the allergy department by an emergency physician. CONCLUSIONS: Acute FPIES should be considered one of the differential diagnoses of vomiting, and pediatric medical staff should be aware of FPIES diagnostic criteria and appropriately refer suspected cases to a specialist.

Relationship between the diagnosis of food protein-induced enterocolitis syndrome and postemetic procalcitonin levels.

Background: There are no reports on the relationship between food protein-induced enterocolitis syndrome (FPIES) diagnosis and procalcitonin levels. Objective: Our study sought to demonstrate a correlation between the presence or absence and severity of FPIES symptoms and postemetic procalcitonin levels. Methods: The subjects were 53 patients with FPIES (44 with hen's egg allergy, 4 with milk allergy, 4 with wheat allergy, and 3 with soy allergy), who collectively underwent a total of 75 oral food challenges (OFCs). Procalcitonin levels at 5 hours after antigen ingestion were compared between patients with a positive OFC result and those with a negative OFC result and between patients who experienced mild or moderate events and those who experienced severe events. Results: At 5 hours after ingestion of the causative food, the median procalcitonin levels in patients with a negative OFC result, patients who experienced a mild or moderate event, and patients who experienced a severe event were 0.02, 0.03, and 0.16 ng/mL, respectively. The procalcitonin level was significantly higher in the groups with a positive OFC result than in the groups with a negative OFC result (P < .001), and it was significantly higher in those who experienced severe events than in those who experienced mild or moderate events (P = .012). Conclusion: Measurement of procalcitonin levels has the potential to provide a quantitative and objective assessment of FPIES diagnosis and severity.