Relevant features of adult-onset food protein–induced enterocolitis syndrome

The Role of IgE Sensitization in Acute FPIES: A Systematic Review and Meta-Analysis

BACKGROUND

Evidence on the role of immunoglobulin E (IgE) sensitization in acute food protein-induced enterocolitis syndrome (atypical FPIES) is limited. Initial reports claimed association with persistent disease; however, recent studies have not replicated this.

OBJECTIVE

To systematically review the relationship between sensitization to the culprit food(s) in acute FPIES and the outcome of follow-up oral food challenges. To assess the rates of sensitization, seroconversion (ie, switch from negative tests to sensitization), and phenotype switch to IgE-mediated food allergy over time in individuals with acute FPIES.

METHODS

Systematic review searching 10 databases. Studies of children and adults with an acute FPIES diagnosis assessing IgE sensitization to a culprit food at onset or follow-up measured by skin prick or serological test were included.

RESULTS

Of 1,830 studies identified, 53 were eligible including 3,514 participants. Ten studies had an analytical design assessing whether sensitization was associated with disease persistence, with 4 showing an association and 6 showing no association. In individuals with acute FPIES, the sensitization rate was 9.8% (95% confidence interval [95% CI 7.4%-12.1%; 34 studies, 2,587 participants, I2 = 82%); the frequency of seroconversion was 1.1% (95% CI 0.1%-2.1%; 9 studies, 673 participants, I2 = 32%); and phenotype switch occurred in 1.1% (95% CI 0.4%-1.7%; 14 studies, 935 participants, I2 = 0%) and 13% (95% CI 5.5%-20.5%, 12 studies, 93 participants; I2 = 18%) of sensitized participants.

CONCLUSIONS

We did not find consistent evidence for the relationship between IgE sensitization and FPIES persistence. We found phenotype switch to IgE-mediated food allergy is uncommon in acute FPIES. An IgE sensitization in FPIES does not have a clear relationship with clinical outcomes.

Oral Food Challenge Protocols in Food Protein-Induced Enterocolitis Syndrome: A Systematic Review

BACKGROUND

Oral food challenges (OFCs) are essential for the diagnosis and follow-up of acute food protein-induced enterocolitis syndrome (FPIES) because no diagnostic or prognostic biomarkers are available. However, the optimal OFC procedure remains unclear.

OBJECTIVE

This systematic review aimed to assess OFC procedures' design and clinical outcomes in patients with FPIES.

METHODS

We searched 10 databases for studies published in English between 1978 and February 2024 involving children or adults undergoing OFC for FPIES. Critical appraisal followed Effective Public Health Practice Project parameters.

RESULTS

In total, 52 studies met inclusion criteria, all observational studies. Of these, 35 were judged to have strong methodological quality. There was great heterogeneity in OFC procedures, particularly in cumulative dose, number, size, and timing between doses. Oral food challenge outcome reporting was often inadequate, especially regarding reaction symptoms and severity grading. In single-dose OFC protocols, most children reacted after at least 2 hours. Four small studies showed that a single dose of 25% of an age-appropriate portion was sufficient to trigger reactions in 80% to 100% of cases, and this was associated with less severe reactions. Owing to methodological heterogeneity and insufficient outcome reporting, further assessment of the OFC protocol characteristics associated with safer outcomes was not possible.

CONCLUSIONS

There is significant heterogeneity in FPIES OFC practices. Current recommendations for OFC procedures and outcome assessments have limitations and should be revisited, because this may affect patient safety and diagnostic accuracy. Future studies should focus on standardizing clinical outcomes and generating evidence to support safer, more accurate OFC protocols in FPIES.

Clinical-Hematological Changes and Predictors of Severity in Acute Food Protein-Induced Enterocolitis Syndrome Reactions at Oral Food Challenge: A Multicenter Observational Study

BACKGROUND

Oral food challenge (OFC) is the criterion 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-hematological changes and predictors of severity of FPIES reactions at OFC.

METHODS

This was an observational multicenter prospective study. Children aged 0 to 18 years diagnosed with acute FPIES were recruited at follow-up OFC in 12 tertiary centers in Spain and Italy. OFC outcomes (as positive/negative/inconclusive and mild/moderate/severe) were assessed on the basis of published "2017 FPIES Consensus" criteria. Clinical characteristics were recorded, and full blood cell count was done at baseline, reaction onset, and 4 hours later. Regression analysis was performed to assess predictors of severe reactions at OFC.

RESULTS

A total of 81 children had positive OFC (mild in 11% [9 of 81], moderate in 61% [49 of 81], and severe in 28% [23 of 81]). Increase in neutrophils and reduction in eosinophils, basophils, and lymphocytes were observed (P < .05). OFC was inconclusive in 19 cases despite objective signs or neutrophilia. Regression analysis showed that a 2-day OFC protocol where only 25% of an age-appropriate portion is given on day 1 (not sex, age, culprit food, cumulative dose, and previous reaction severity) was associated with reduced odds of severe reaction compared with giving multiple doses in a single day.

CONCLUSIONS

Distinct hematological 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 be associated with a reduced risk of severe reactions. Future work should aim to develop safer OFC and non-OFC diagnostics for FPIES.

Current and future perspectives on the consensus guideline for food protein-induced enterocolitis syndrome (FPIES)

Food protein-induced enterocolitis syndrome (FPIES) is a non-IgE mediated food allergy presenting with delayed onset of projectile vomiting in the absence of cutaneous and respiratory symptoms. The pathophysiology of FPIES remains poorly characterized. The first international consensus guidelines for FPIES were published in 2017 and provided clinicians with parameters on the diagnosis and treatment of FPIES. The guidelines have served as a resource in the recognition and management of FPIES, contributing to an increased awareness of FPIES. Since then, new evidence has emerged, shedding light on adult-onset FPIES, the different phenotypes of FPIES, the recognition of new food triggers, center-specific food challenge protocols and management of acute FPIES. Emerging evidence indicates that FPIES impacts both pediatric and adult population. As a result, there is growing need to tailor the consensus guidelines to capture diagnoses in both patient groups. Furthermore, it is crucial to provide food challenge protocols that meet the needs of both pediatric and adult FPIES patients, as well as the subset of patients with atypical FPIES. This review highlights the evolving clinical evidence relating to FPIES diagnosis and management published since the 2017 International FPIES Guidelines. We will focus on areas where recent published evidence may support evolution or revision of the guidelines.

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.

The epidemiology of food allergy in adults

The prevalence and awareness of food allergy (FA) among US adults is arguably at a historical high, both with respect to primary immunoglobulin E-mediated food hypersensitivity and other food-triggered conditions that operate through a variety of immunologic mechanisms (eg, pollen-FA syndrome, alpha-gal syndrome, food protein-induced enterocolitis syndrome, eosinophilic esophagitis). Worryingly, not only are many adults retaining childhood-onset food allergies as they age into adulthood, it seems that many adults are experiencing adult-onset allergies to previously tolerated foods, with correspondingly adverse physical, and psychological health impacts. Consequently, this review aims to summarize what is currently known about the epidemiology and population-level burden of FA among adult populations in North America and around the globe. This article also provides insights into the natural history of these conditions and what we need to know as we look to the future to support effective care and prevent FA.

Food Protein-Induced Enterocolitis Syndrome in Adulthood: Clinical Characteristics, Prognosis, and Risk Factors

BACKGROUND

Food protein-induced enterocolitis syndrome (FPIES) in adults is being increasingly recognized; however, little is known about its characteristics.

OBJECTIVE

To describe the clinical characteristics, prognosis, and associated factors in adult FPIES.

METHODS

A 10-year prospective study was conducted in the Allergy Section of Alicante General Hospital in adults diagnosed with FPIES. Detailed interviews with patients and oral food challenges (OFCs) were performed to confirm diagnosis or evaluate for tolerance. Comorbidities and possible risk factors were analyzed retrospectively through electronic medical records to assess their association with the disease.

RESULTS

One hundred and seven adults with FPIES (93.5% female) were followed for a median of 6.2 years. Abdominal pain was the most common manifestation (96.3%), followed by diarrhea (72%) and vomiting (60.7%). Seafood (59.8%), egg (14%), and milk (10.3%) were the most common triggers, whereas 43.9% reacted to more than 1 food group. We performed 49 OFCs: 9 to confirm diagnosis and 40 to evaluate for tolerance. After a median 3.5 years, 16.8% achieved tolerance. Resolution was correlated inversely with duration of the disease (P = .04) and seafood (P = .023) but not with age of onset. The prevalence of gastrointestinal pathologies such as irritable bowel syndrome (IBS), eosinophilic esophagitis, inflammatory bowel disease, and celiac disease was higher than in the general population. A higher number of FPIES triggers were correlated with also having a diagnosis of IBS (P = .02).

CONCLUSIONS

Although adult FPIES normally persists, some patients achieve tolerance. Adults with FPIES have a relatively high prevalence of gastrointestinal pathologies. The predominance of women may be related to hormonal factors. The clinical differences with pediatric FPIES warrant a revision of diagnostic criteria in adults.

The Natural Course of Adult-Onset Food Protein-Induced Enterocolitis Syndrome

BACKGROUND

Adult-onset food protein-induced enterocolitis syndrome (FPIES) has been increasingly recognized in recent years. Adult FPIES differs from pediatric FPIES in terms of dietary triggers and symptoms, thus further broadening the clinical phenotypes of the disease. The natural history of FPIES in adulthood is poorly characterized.

OBJECTIVE

To evaluate the natural course of FPIES in adults.

METHODS

We performed an ambispective study of adults diagnosed with acute FPIES during 2016-2021. Data on age, sex, symptoms, implicated food, and oral food challenge (OFC) outcomes at baseline and during follow-up were analyzed.

RESULTS

Forty-two adults were included (83.3% female; median age at diagnosis, 40 years). The predominant symptoms were diarrhea (92.9%) and abdominal cramps (71.4%); vomiting was reported by 59% of patients. The most common triggers were shellfish (n = 19, 45.2%) and fish (n = 19, 45.2%). The mean number of reactions before diagnosis was 6.3 (2-15). Twenty-one OFCs were carried out with the offending food in 15 patients. Six patients achieved tolerance (40%) after a mean of 17.8 months (range, 6-36 months). Twelve of all OFCs performed were positive (57.1%). The absolute leukocyte and neutrophil counts measured before and 1 to 2 hours after the positive challenge showed a mean increase of 3045 and 2736 cells/μL, respectively. Serum tryptase, C-reactive protein, and eosinophil and platelet values did not change significantly after the OFC.

CONCLUSION

Some patients may outgrow adult-onset FPIES.

Adult Food Protein-Induced Enterocolitis Syndrome

Food protein-induced enterocolitis syndrome (FPIES) is a non-IgE, cell-mediated food allergy, commonly diagnosed in infants and young children. In recent years, new-onset adult FPIES has been recognized. The underlying pathogenic mechanism of FPIES has yet to be elucidated, thus disease-specific diagnostic biomarkers have yet to be determined and an oral food challenge (OFC) remains the gold-standard for the diagnosis. Pediatric patients with FPIES classically present with symptoms of delayed, repetitive vomiting approximately 1 to 4 hours following ingestion of a food allergen. However, adults with FPIES have been reported to have a different symptom profile and different food triggers compared to the pediatric FPIES population. The current FPIES diagnostic criteria may not be appropriate for the diagnosis of adult FPIES patients, thus an oral food challenge remains a diagnostic tool. This review provides an overview of the current literature on the clinical presentation, epidemiology, diagnosis, triggers and management of adult FPIES.

Update on Food Protein-Induced Enterocolitis Syndrome (FPIES)

PURPOSE OF REVIEW

Food protein-induced enterocolitis syndrome (FPIES) is a non-IgE-mediated food allergy characterized by delayed, and potentially severe, gastrointestinal symptoms. Since the advent of a specific diagnostic code and establishment of diagnostic guidelines, our understanding of this condition has grown.

RECENT FINDINGS

FPIES affects patients from early infancy into adulthood. Any food can be a trigger, and common culprit foods vary geographically and by age. An understanding of the complex underlying immune mechanisms remains elusive, although studies show pan-leukocyte activation, cytokine release, and increased gastrointestinal permeability. Management involves trigger avoidance, and patients may benefit from the support of a dietitian to ensure adequate nutrient intake. Tolerance develops over time for most children, but due to the risk of severe symptoms, re-introduction of a suspected FPIES trigger is recommended only under supervision at an oral food challenge. Studies continue to evaluate the optimal challenge protocol. Caregivers of children with FPIES report high levels of anxiety and stress, which is attributed to the dramatic symptomatology, dietary restrictions, nutritional concerns, lack of confirmatory diagnostic tests, and limited tools for management of reactions. Our understanding of the FPIES diagnosis has improved over the last few decades, but there remain opportunities, particularly regarding discerning the pathophysiology and best management practices.

Alternative Fish Species for Nutritional Management of Children with Fish-FPIES—A Clinical Approach

In the Mediterranean region, fish is a common cause of food protein-induced enterocolitis syndrome (FPIES) in children. No laboratory tests specific to FPIES are available, and oral food challenge (OFC) is the gold standard for its diagnosis and testing for achievement of tolerance. Children with FPIES to fish are usually advised to avoid all fish, regardless of the species. Fish are typically classified into bony and cartilaginous, which are phylogenetically distant species and therefore contain less cross-reacting allergens. The protein β-parvalbumin, considered a pan-allergenic, is found in bony fish, while the non-allergenic α-parvalbumin is commonly found in cartilaginous fish. Based on this difference, as a first step in the therapeutic process of children with FPIES caused by a certain fish in the bony fish category (i.e., hake, cod, perch, sardine, gilthead sea bream, red mullet, sole, megrim, sea bass, anchovy, tuna, swordfish, trout, etc.), an OFC to an alternative from the category of cartilaginous fish is suggested (i.e., blue shark, tope shark, dogfish, monkfish, skate, and ray) and vice versa. Regarding the increased mercury content in some sharks and other large species, the maximum limit imposed by the European Food Safety Authority (EFSA) for weekly mercury intake must be considered. An algorithm for the management of fish-FPIES, including alternative fish species, is proposed.

Advances in understanding immune mechanisms of food protein-induced enterocolitis syndrome

OBJECTIVE

This review provides an overview of our current understanding of the mechanisms of food protein-induced enterocolitis syndrome (FPIES).

DATA SOURCES

To capture recent articles published since our previous comprehensive review on the pathophysiology of FPIES, we performed a literature search through PubMed database, using the search terms FPIES and food protein-induced enterocolitis syndrome from 2016 to the current year.

STUDY SELECTIONS

Studies in English containing biomarker or immune data were reviewed and summarized.

RESULTS

Studies of peripheral blood fail to exhibit evidence of antigen-specific humoral or cellular immunity underlying clinical reactivity to foods in FPIES. However, growing evidence suggests a robust systemic innate immune activation occurring during FPIES reactions and the activation of neuroendocrine pathways.

CONCLUSION

FPIES reactions are associated with marked activation of innate immune and neuroendocrine pathways; however, the mechanism underlying the specific recognition of foods remains elusive.