Functional Constipation: Pathophysiology, evaluation, and management

BACKGROUND

Functional constipation (FC), a disorder of the gut-brain interaction of multifactorial pathophysiology that is prevalent in paediatrics. It is associated with bothersome symptoms, increased healthcare costs, disgruntled caregivers and impaired health-related quality of life. Paediatric FC is a clinical diagnosis based on the Rome IV criteria and is characterised by decreased bowel movement frequency and/or hard, painful stools and can be complicated by retentive faecal incontinence. Stressful life events, difficult temperaments and emotional and behavioural challenges have been implicated in increasing risk of developing paediatric FC.

AIMS

To provide current concepts in pathophysiology, evaluation and management of paediatric FC.

METHODS

We reviewed pertinent literature after a comprehensive search utilising PubMed with keywords FC, chronic childhood constipation and paediatric FC.

RESULTS

In the last decade, advances in our understanding of paediatric FC have changed the landscape of diagnosing and treating this disorder. Although polyethylene glycol is the first-line treatment for maintenance of FC, the armamentarium of therapeutics has expanded including the first Food and Drug Administration- agent, linaclotide, for children 6-17 years of age in conjunction with more emphasis on behavioural and physical therapy interventions.

CONCLUSIONS

Treatment approach to paediatric FC should be individualised and integrated focusing on parental education, lifestyle and behavioural modifications, and pharmacological therapy to maximise therapeutic success. This review highlights advances in pathophysiology, diagnosis and treatment of FC in children.

Diagnosis and management of food allergy-induced constipation in young children-An EAACI position paper

The recognition of constipation as a possible non-Immunoglobulin E (IgE)-mediated allergic condition is challenging because functional constipation (unrelated to food allergies) is a common health problem with a reported worldwide prevalence rate of up to 32.2% in children. However, many studies in children report challenge proven cow's milk allergy and constipation as a primary symptom and have found that between 28% and 78% of children improve on a cow's milk elimination diet. Due to the paucity of data and a focus on IgE-mediated allergy, not all food allergy guidelines list constipation as a symptom of food allergy. Yet, it is included in all cow's milk allergy guidelines available in English language. The Exploring Non-IgE-Mediated Allergy (ENIGMA) Task Force (TF) of the European Academy for Allergy and Clinical Immunology (EAACI) considers in this paper constipation in the context of failure of standard treatment and discuss the role of food allergens as culprit in constipation in children. This position paper used the Delphi approach in reaching consensus on both diagnosis and management, as currently published data are insufficient to support a systematic review.

Very early onset perinatal constipation: Can it be cow's milk protein allergy?

Delayed passage of meconium or constipation during the perinatal period is traditionally regarded as a signal to initiate further work up to evaluate for serious diagnoses such as Hirschsprung's disease (HD), meconium ileus due to Cystic Fibrosis, etc. The diagnosis of HD particularly warrants invasive testing to confirm the diagnosis, such as anorectal manometry or rectal suction biopsy. What if there was another etiology of perinatal constipation, that is far lesser known? Cow's milk protein allergy (CMPA) is often diagnosed in infants within the first few weeks of life, however, there are studies that show that the CMPA allergen can be passed from mother to an infant in-utero, therefore allowing symptoms to show as early as day one of life. The presentation is more atypical, with perinatal constipation rather than with bloody stools, diarrhea, and vomiting. The diagnosis and management would be avoidance of cow's milk protein within the diet, with results and symptom improvement in patients immediately. Therefore, we discuss whether an alternative pathway to address perinatal constipation should be further discussed and implemented to potentially avoid invasive techniques in patients. This entails first ruling out CMPA with safe, noninvasive techniques with diet modification, and if unsuccessful, then moving forward with further diagnostic modalities.

A narrative review on the diagnosis and management of constipation in infants

INTRODUCTION

Functional constipation is one of the common disorders of gut-brain interaction in infancy, and decreases the quality of life of infants and parents.

AREAS COVERED

Relevant articles up to November 2022 were reviewed. We searched in PubMed, Google Scholar, and MEDLINE for guidelines, position papers, reviews, and randomized controlled trials on infant constipation.

EXPERT OPINION

Randomized controlled trials in this specific age group are mostly limited to trials with infant formula. The prevalence of infant constipation in formula-fed infants is decreasing, and can be associated with adaptations in formula composition. While the supplementation of infant formula with pro-, pre- and/or synbiotics decreases the prevalence of constipation, their efficacy in constipated infants is disappointing. There is limited evidence to support the addition of magnesium to infant formula to treat constipation. The evidence for the efficacy and safety of polyethylene glycol in children < 2 years has expanded over the past years. The administration of lactulose or polyethylene glycol is the preferred medical management, in case nutritional management does result in insufficient improvement.

Impact of a dietitian in general practice: paediatric food allergy

BACKGROUND

Food allergy in infants and young children places a significant burden on primary care. This study evaluated a dietetic-led paediatric food allergy service, which attempts to provide more rapid access to the dietitian and reduce the need for general practitioner (GP) and secondary care appointments.

METHODS

Two community dietetic services for children referred with food allergy were compared. The first was dietetic-led care where dietitians train community children's nurses to recognise potential cases of food allergy, undertake basic diagnostic assessment and subsequently refer to the dietitian. The other was a more traditional dietetic community service where patients were referred predominantly by the GP or secondary care.

RESULTS

In dietetic-led care 86 patients were seen, compared to 96 in dietetic community care. Dietetic-led care received fewer referrals from the GP, 36% versus 67% (p < 0.001); GP appointments for allergy-related conditions prior to dietetic referral were lower, 3 versus 6 visits (p = 0.001); and input from secondary care was also lower, 8 versus 25 patients (p = 0.002) compared with dietetic community care. Children referred to dietetic-led care were younger, 78% <6 months versus 40% (p < 0.001) in dietetic community care.

CONCLUSIONS

Dietetic-led care describes a model that has the potential to reduce GP and secondary care appointments, identify patients more quickly and reduce the time to receive dietetic input, thereby resolving symptoms more quickly and reducing prescribed medications. This model demonstrates the importance of integrated care and multidisciplinary working, offering a solution to reducing GP workload while maintaining or improving patient care.

Network-Based Elaboration of the Efficacy of the Dachangshu (BL25) and Tianshu (ST25) Points in the Treatment of Functional Constipation in Children through Inflammation, Adipocytokine, or Leptin Pathways

Constipation commonly occurs during childhood, and more than 95% of cases are classified as functional constipation. If not effectively treated, 20% of patients with childhood constipation can continue to exhibit symptoms into adulthood, which seriously affects their mental health and quality of life. The main feature of acupuncture or acupoint stimulation, a special branch of traditional Chinese medicine, is the selection of different acupoints for different diseases, and many worthy guidelines have been established for matching acupoints. The back-shu and front-mu point combination adheres to an important acupoint compatibility law that has been used since its proposal 2,500 years ago but has not yet been verified by the modern evidence-based experiments. This study focused on the back-shu and front-mu point combination using the Dachangshu (BL25) and Tianshu (ST25) points as examples to explore possible research methods for network acupoint-based stimulation based on existing evidence and to elucidate the mechanisms induced by BL25 and ST25 in the treatment of functional constipation in children (FCC). The study found that BL25 and ST25 have 20 common targets, namely, AQP8, DRD2, VIP, TAC1, IL6R, TNF, FOS, KIT, CHAT, HTR3A, GAS8, SOD3, TRPV1, MPO, CALCA, IL1B, P2RX7, NPY2R, IL10RA, and TPH1, and these targets may provide a strategy for the combined usage of BL25 and ST25. In addition, BL25 and ST25 can affect FCC treatment through inflammation-relatedTh17-cell differentiation, the NF-kappa B signaling pathway, and the Toll-like receptor signaling pathway. Adipocytokines or leptin may also comprise the mechanism through which BL25 and ST25 regulate FCC. In addition, BL25 and ST25 regulate FCC through 13 core targets, namely, NFKBIA, RELA, TNF, IKBKB, IRAK1, TLR4, MYD88, TNFRSF1A, IL1R1, TLR2, IL1B, TRAF6, and TNFRSF1B. In short, this study provides new ideas and methods for studying the mechanism of acupuncture points.

Constipation in Children and Adolescents

BACKGROUND

According to a population-based study, approximately 6.8% of children and adolescents in Germany suffer from acute or chronic constipation. It can be of organic or functional origin and may be associated with comorbid disturbances, particularly fecal incontinence.

METHODS

We selectively searched the PubMed and Google Scholar databases for articles with the keywords "constipation," "children and adolescents," and "incontinence". Recommendations are based on the AWMF guideline on constipation and fecal incontinence and on international guidelines and reviews.

RESULTS

More than 90% of cases of chronic constipation are of functional origin. Organic causes vary with age and call for targeted differential diagnosis. Invasive tests are only rarely necessary. Functional constipation may be associated with fecal and urinary incontinence, and the relative risk of urinary tract infections is 2.2 to 6.5. There may be associated psychological symptoms and mental disorders in 30-50% of cases. The cornerstone of treatment is patient and parent education, along with laxative medication and toilet training. Instructional programs have been found effective in otherwise refractory cases.

CONCLUSION

The treatment of constipation in childhood should begin as soon as the differential diagnostic evaluation is completed. The education of parents, follow-up at close intervals, and drug treatment and behavioral therapy that are adapted to the symptoms can improve quality of life.

Cows' Milk Allergy-Associated Constipation: When to Look for It? A Narrative Review

Constipation is a very common disorder, mostly functional in nature, that may persist for years in up to 35-52% of children. Food allergy prevalence, severity and persistence are increasing over time, and cows' milk protein is the commonest food allergen recognised to affect gastrointestinal motility in children. There is mounting evidence of the role of cows' milk (CM) allergy (CMA) in children with constipation. With this narrative review, we aim to provide clinicians with an updated and critical overview of food allergy-associated constipation. We searched Embase, Medline and the Cochrane Library, using keywords related to the topic. Only reviews and studies including children aged 0-17 years that were published in English were considered. Constipation has been reported in 4.6% of infants with CMA; the prevalence of food allergy underlying chronic constipation in children resistant to conventional treatment and presenting to tertiary clinics ranges between 28% and 78%. The identification of predisposing risk factors and of a specific phenotype of food allergy-induced constipation remains elusive. No allergic tests, radiological or motility investigations achieve sufficient sensitivity and specificity to screen children for CMA-related constipation. A 4-week cows' milk protein (CMP) elimination diet may be considered for children with chronic constipation resistant to conventional treatment and who lack alarm sign/symptoms of organic diseases. In subjects with ameliorated symptoms on CMP elimination, the diagnosis of CMA should be confirmed by a food challenge to avoid an unnecessary protracted diet.

Case Reports of Cow's Milk Protein Allergy Presenting as Delayed Passage of Meconium With Early Onset Infant Constipation

A cellular proliferation to milk allergens has been found in the cord blood cells of neonates. While this reflects a sensitivity during the fetal life, its clinical significance and disease, particularly its unconventional presentations, have remained largely unrecognized by care providers. Here, we report three cases of infants whose mothers consumed dairy products during pregnancy, who developed a severely constipated pre- and postnatal bowel. The passage of meconium was significantly delayed with subsequent early-onset infant constipation that was intractable to conventional therapies but remitted when milk proteins were withheld, recurred when milk proteins were reintroduced, and resolved again when switched to an extensively hydrolyzed or amino acid-based infant formula. Based on this and other observations, it is believed that these infants must have initiated and/or developed cow's milk protein allergy prenatally during fetal life. We suggest that a 2-week trial of cow's milk protein avoidance be applied to these neonate infants with early-onset constipation before an unnecessary invasive work-up for Hirschsprung disease and others is initiated per the current guidelines.

Nonpharmacologic Treatment for Children with Functional Constipation: A Systematic Review and Meta-analysis

OBJECTIVE

To evaluate the effectiveness and safety of nonpharmacologic interventions for the treatment of childhood functional constipation.

STUDY DESIGN

Randomized controlled trials (RCTs) evaluating nonpharmacologic treatments in children with functional constipation which reported at least 1 outcome of the core outcome set for children with functional constipation.

RESULTS

We included 52 RCTs with 4668 children, aged between 2 weeks and 18 years, of whom 47% were females. Studied interventions included gut microbiome-directed interventions, other dietary interventions, oral supplements, pelvic floor-directed interventions, electrical stimulation, dry cupping, and massage therapy. An overall high risk of bias was found across the majority of studies. Meta-analyses for treatment success and/or defecation frequency, including 20 RCTs, showed abdominal electrical stimulation (n = 3), Cassia Fistula emulsion (n = 2), and a cow's milk exclusion diet (n = 2 in a subpopulation with constipation as a possible manifestation of cow's milk allergy) may be effective. Evidence from RCTs not included in the meta-analyses, indicated that some prebiotic and fiber mixtures, Chinese herbal medicine (Xiao'er Biantong granules), and abdominal massage are promising therapies. In contrast, studies showed no benefit for the use of probiotics, synbiotics, an increase in water intake, dry cupping, or additional biofeedback or behavioral therapy. We found no RCTs on physical movement or acupuncture.

CONCLUSIONS

More well-designed high quality RCTs concerning nonpharmacologic treatments for children with functional constipation are needed before changes in current guidelines are indicated.

Management of functional constipation in children and adults

Functional constipation is common in children and adults worldwide. Functional constipation shows similarities in children and adults, but important differences also exist regarding epidemiology, symptomatology, pathophysiology, diagnostic workup and therapeutic management. In children, the approach focuses on the behavioural nature of the disorder and the initial therapeutic steps involve toilet training and laxatives. In adults, management focuses on excluding an underlying cause and differentiating between different subtypes of functional constipation - normal transit, slow transit or an evacuation disorder - which has important therapeutic consequences. Treatment of adult functional constipation involves lifestyle interventions, pelvic floor interventions (in the presence of a rectal evacuation disorder) and pharmacological therapy. When conventional treatments fail, children and adults are considered to have intractable functional constipation, a troublesome and distressing condition. Intractable constipation is managed with a stepwise approach and in rare cases requires surgical interventions such as antegrade continence enemas in children or colectomy procedures for adults. New drugs, including prokinetic and prosecretory agents, and surgical strategies, such as sacral nerve stimulation, have the potential to improve the management of children and adults with intractable functional constipation.

'Rapid transit' constipation in children: a possible genesis for irritable bowel syndrome

Children with chronic idiopathic constipation (CIC) often end up at the surgeon when medical treatments have failed. This opinion piece discusses a recently described pattern of CIC called 'Rapid transit constipation (RTC)' first identified in 2011 as part of surgical workup. RTC was identified using a nuclear medicine gastrointestinal transit study (NMGIT or nuclear transit study) to determine the site of slowing within the bowel and to inform surgical treatment. Unexpectedly, we found that RTC occured in 29% of 1000 transit studies in a retrospective audit. Irritable bowel syndrome (IBS) occurs in 7-21% of the population, with a higher prevalence in young children and with constipation type dominating in the young. While 60% improve with time, 40% continue with symptoms. First-line therapy for IBS in adults is a diet low in fermentable oligosaccharides, disaccharides, monosaccharides and polyols which reduces symptoms in > 70% of patients. In children with functional gastrointestinal disorders, fructose intolerance occurs in 35-55%. Reducing fructose produced significant improvement in 77-82% of intolerant patients. In children with RTC and a positive breath test upon fructose challenge, we found that exclusion of fructose significantly improved constipation, abdominal pain, stool consistency and decreased laxative use. We hypothesise that positive breath tests and improvement of pain and bowel frequency with sugar exclusion diets in RTC suggest these children have IBS-C. These observations raise the possibility that many children with CIC could be treated by reducing fructose early in their diet and this might prevent the development of IBS in later life.

Functional constipation in infancy and early childhood: epidemiology, risk factors, and healthcare consultation

Background

Functional constipation (FC) is a pediatric problem that is seen frequently. However, its prevalence in Asia remains undetermined. In this study we attempted to determine the prevalence, risk factors and therapeutic modalities of FC in infants and toddlers in Sri Lanka.

Methods

Children aged 6.5 months to 4 years were selected from 14 well-baby and vaccination clinics in the Gampaha District of Sri Lanka. A questionnaire with questions regarding the socio-demographic characteristics, child’s bowel habits, psycho-social risk factors and treatment modalities were filled by the mothers. FC was diagnosed according to ROME III criteria.

Results

A total of 1113 children were analyzed [(female n = 560 (50.3%) with a mean age of 20.7 months, standard deviation [SD] 11.2 months. FC was found in 89 (8.0%). FC was significantly and independently associated with underweight (14.3% vs 7.2%, p = 0.008. [OR and 95% CI: 2,3 (CI; 1.3–4.2)] and residence in an urban area (9.6% vs 5.6%, p = 0.013). [OR and 95% CI: 0.592 (CI; 0.396–0.95)]. Children subjected to violence showed a significantly higher prevalence of FC (20.0 vs 7.8%, p = 0.046). Children being overweight and children living with mothers subjected to violence showed a higher, though not statistically significant, tendency to develop FC. Children with FC visited healthcare clinics more frequently when compared to controls (19.6% vs 6.0%, p < 0.0001). However, only 24% of infants and toddlers with FC were treated specifically for the condition by a doctor.

Conclusions

FC occurred in 8% of this cohort of Sri Lankan infants and toddlers. It is significantly associated with underweight and living in an urban area. Only a quarter of them received medical attention for their constipation.

Trial registration

SLCP/ERC/2014/12, December 2014.

Electronic supplementary material

The online version of this article (10.1186/s12887-019-1652-y) contains supplementary material, which is available to authorized users.

Non-IgE-mediated gastrointestinal allergies-Do they have a place in a new model of the Allergic March

The rise in food allergy has been described as the "second wave" of the allergy epidemic, with some developed countries reporting a prevalence of 10% of challenge-proven food allergies. Recognition of the Allergic March has played a crucial role in identifying causality in allergic conditions, linking atopic dermatitis to food allergy and food allergy to other atopic disorders, thereby highlighting opportunities in prevention and the importance of early intervention. This publication will establish the value of weaving the less well-understood, non-IgE-mediated food allergy into the Allergic March and mapping its progression through childhood and its associated co-morbidities. The proposed non-IgE-mediated Allergic March highlights the concomitant presentation of gastrointestinal symptoms and atopic dermatitis as early presenting symptoms in confirmed non-IgE-mediated allergies and the later development of atopic co-morbidities, including asthma and allergic rhinitis, similar to the IgE-mediated Allergic March. This publication highlights recent observations of a link between non-IgE-mediated food allergy in early childhood and functional gastrointestinal disorders in later life and also the reported occurrence of extra-intestinal manifestations at later ages. Although significant limitations exist in regard to the proposed evolution of the Allergic March model, the authors hope that this publication will influence the management of non-IgE-mediated gastrointestinal allergies and inform future research and interventions.

[Non-IgE-mediated cow's milk allergy: Consensus document of the Spanish Society of Paediatric Gastroenterology, Hepatology, and Nutrition (SEGHNP), the Spanish Association of Paediatric Primary Care (AEPAP), the Spanish Society of Extra-hospital Paediatrics and Primary Health Care (SEPEAP), and the Spanish Society of Paediatric ClinicaL Immunology, Allergy, and Asthma (SEICAP)]

Non-IgE-mediated cow's milk allergy is a frequent disorder in paediatrics. As patients might be seen by professionals from different specialties and levels of expertise, a great variability in diagnostic procedures and disease monitoring is commonly observed. Therefore, four scientific societies involved in its management have developed a consensus document providing specific recommendations related to its prevention, diagnosis, treatment and follow up.

Cow's Milk Protein Allergy in Infancy: A Risk Factor for Functional Gastrointestinal Disorders in Children?

The role and prevalence of cow's milk protein allergy (CMA) in functional gastrointestinal disorders remains unclear. The aim of this review is to update knowledge on the relationship between CMA and functional abdominal pain disorders (FAPDs) in children. Cochrane Database and Pubmed were searched from inception using general and specific terms for CMA and functional gastrointestinal disorders. CMA is reported as a predisposing or coexisting factor in a wide range of functional gastrointestinal disorders in infants and children. Pathogenesis of both conditions is complex and multiple mechanisms including dysmotility and hypersensitivity might contribute to the clinical manifestations. Data supporting the possible role of food allergies in the pathogenesis of FAPDs are limited. CMA may predispose to early life inflammation and visceral hypersensitivity, which in turn might manifest as FAPDs. The diagnosis of either CMA or FAPDs and distinction between them is challenging because of nonspecific and overlapping symptoms. Lack of accurate allergy tests in non-IgE (immunoglobulin E) mediated cases is also problematic. Oral food challenge, following an elimination diet, should be performed to diagnose a suspected non-IgE CMA allergy in children with FAPDs. In the management of FAPDs, an elimination diet should be considered for a limited period to verify if the symptoms improve or resolve.

Functional constipation in children: challenges and solutions

This review intends to update what is known about and what is still a challenge in functional constipation (FC) in children regarding epidemiology, pathophysiology, diagnosis, and management. Although FC is a common childhood problem, its global burden remains unknown as data from parts of the world are missing. Another problem is that there is a large variation in prevalence due to differences in study methods and defining age groups. The pathophysiology of FC remains unclear to date but is probably multifactorial. Withholding behavior is likely to be the most important factor in toddlers and young children. Genetics may also play a role since many patients have positive family history, but mutations in genes associated with FC have not been found. Over the past years, different diagnostic criteria for FC in infants and children have been proposed. This year, Rome IV criteria have been released. Compared to Rome III, it eliminates two diagnostic criteria in children under the age of 4 who still wear diapers. Physical examination and taking a thorough medical history are recommended, but other investigations such as abdominal radiography, transabdominal recto-ultrasonography, colonic transit time, rectal biopsies, and colon manometry are not routinely recommended. Regarding treatment, guidelines recommend disimpaction and maintenance therapy with polyethylene glycol (PEG) with or without electrolytes. But experience shows that acceptability, adherence, and tolerance to PEG are still a challenge. Counseling of parents and children about causes of FC is often neglected. Recent studies suggest that behavior therapy added to laxative therapy improves the relief of symptoms. Further homogeneous studies, better-defined outcomes, and studies conducted in primary care are needed.

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.

Food Protein-Induced Non-Immunoglobulin E-Mediated Allergic Colitis in Infants and Older Children: What Cytokines Are Involved?

BACKGROUND

Food protein-induced allergic proctocolitis (FPIAP) is mostly a non-immunoglobulin E-mediated disease where a T-cell-mediated reaction to cow's milk protein has been suggested. We determined the expression of transforming growth factor (TGF)-β, TGF-β receptor-1, tumor necrosis factor (TNF)-α, CD86, and CD23 on the colon mucosa to investigate their roles in the pathogenesis of the two subtypes of FPIAP, i.e. infantile FPIAP and FPIAP in older children.

METHODS

Group 1 comprised children with infantile FPIAP (age <6 months, n = 21), group 2 referred to FPIAP in older children (age >1.5 years, n = 7), and group 3 included children with juvenile hyperplastic polyps (n = 22). Immunohistochemical staining of colonic biopsy specimens was performed.

RESULTS

The expression of TNF-α was significantly higher in groups 1 and 2 compared to group 3. Group 2 patients had a significantly lower TGF-β expression compared to the other groups. The expression of CD86 was higher in group 1 than in group 3 (p = 0.012). Eosinophil counts per high-power field in the lamina propria were significantly correlated with CD86 expression (p = 0.026, r = 0.388).

CONCLUSION

Our results suggest that TNF-α is implicated in the pathogenesis of both types of FPIAP. The decreased activity of TGF-β receptor-1 accompanied by the increased expression of CD86 in infants and the decreased activity of TGF-β in older children appear to play a role in the development of FPIAP.

Non-IgE-mediated gastrointestinal food allergy

Non-IgE-mediated gastrointestinal food-induced allergic disorders (non-IgE-GI-FAs) account for an unknown proportion of food allergies and include food protein-induced enterocolitis syndrome (FPIES), food protein-induced allergic proctocolitis (FPIAP), and food protein-induced enteropathy (FPE). Non-IgE-GI-FAs are separate clinical entities but have many overlapping clinical and histologic features among themselves and with eosinophilic gastroenteropathies. Over the past decade, FPIES has emerged as the most actively studied non-IgE-GI-FA, potentially because of acute and distinct clinical features. FPIAP remains among the common causes of rectal bleeding in infants, while classic infantile FPE is rarely diagnosed. The overall most common allergens are cow's milk and soy; in patients with FPIES, rice and oat are also common. The most prominent clinical features of FPIES are repetitive emesis, pallor, and lethargy; chronic FPIES can lead to failure to thrive. FPIAP manifests with bloody stools in well-appearing young breast-fed or formula-fed infants. Features of FPE are nonbloody diarrhea, malabsorption, protein-losing enteropathy, hypoalbuminemia, and failure to thrive. Non-IgE-GI-FAs have a favorable prognosis; the majority resolve by 1 year in patients with FPIAP, 1 to 3 years in patients with FPE, and 1 to 5 years in patients with FPIES, with significant differences regarding specific foods. There is an urgent need to better define the natural history of FPIES and the pathophysiology of non-IgE-GI-FAs to develop biomarkers and novel therapies.