Prevalence of esophageal eosinophilia and eosinophilic esophagitis in adults: a population-based endoscopic study in Shanghai, China

Long-term course of untreated asymptomatic esophageal eosinophilia and minimally symptomatic eosinophilic esophagitis

Background and study aims The long-term course of untreated asymptomatic esophageal eosinophilia (aEE) and minimally symptomatic eosinophilic esophagitis (mEoE) are not well understood. This study aimed to clarify this course. Patients and methods A total of 36 patients with EE who were endoscopically followed up for more than 5 years, and who underwent more than one endoscopy evaluation after the first diagnosis, were investigated. These patients were divided into two groups according to the presence or absence of the continuous treatment: no treatment group (NT group, n=22) and proton pump inhibitor/potassium competitive acid blocker group (Tx group, n=14). Symptoms and endoscopic and histological findings were retrospectively reviewed according to endoscopic phenotypes. Endoscopic assessment was performed using the EoE endoscopic reference score (EREFS). Results The median follow-up period was 84.5 months in the Tx group and 92 months in the NT group. During the follow-up period, about half of the patients in the Tx-diffuse group persisted EREFS >3, while the remaining half had EREFS ≤2. The total EREFS in the NT-diffuse group remained almost unchanged (median: 2-4) without apparent exacerbation. In contrast, EREFS in the NT-localized group exhibited an unchanged or gradually decreasing trend, with statistical significance from the first diagnosis to 72 to 83 months after. Conclusions Untreated aEE and mEoE are not likely to worsen even without treatment at least for a median follow-up of 7 years. Instead, the localized type may spontaneously improve, implying a different pathogenesis in the presence of the diffuse type. Further studies should clarify the long-term prognosis.

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.

Retrospective cohort study: Effect of age as a barrier to diagnosis of eosinophilic oesophagitis

BACKGROUND

Prior work suggests eosinophilic oesophagitis (EoE) is rare in those aged over 65 years. However, elderly patients with EoE experience a substantial diagnostic delay from symptom onset to diagnosis.

AIMS

To assess if age predicted whether oesophageal biopsies were obtained in patients with EoE symptoms, what clinical features predict EoE in the elderly, and if EoE phenotype differs between elderly and non-elderly patients.

METHODS

We conducted a retrospective cohort study utilising the University of North Carolina (UNC) electronic medical record, EoE clinicopathologic database and UNC endoscopy software from July 2008 to April 2021. A sample of 193 elderly and non-elderly patients with dysphagia, chest pain and/or heartburn were assembled. Patients with EoE were newly diagnosed per contemporaneous guidelines. Patient demographics, clinical characteristics and procedural data were extracted. Summary statistics, bivariate and multivariate analyses were performed.

RESULTS

Of 193 patients, we included 91 elderly (47%) and 102 non-elderly (53%). Age independently predicted the odds of biopsies (adjusted odds ratio (aOR): 0.44 elderly vs. non-elderly; 95% CI: 0.21-0.92). Endoscopic features of EoE, but not symptoms, were more common in elderly than non-EoE elderly patients. Elderly patients with EoE differed from non-elderly only by time to diagnosis (aOR per year of symptoms preceding diagnosis: 1.08, 95% CI: 1.04-1.11).

CONCLUSIONS

Elderly patients with EoE have <50% the odds of oesophageal biopsies. There were no significant differences between elderly and non-elderly EoE patients, although endoscopic features helped discriminate the two groups. Our findings suggest that older age represents a barrier to EoE diagnosis.

Eosinophilic esophagitis in children: A cross-sectional study from a tertiary care center

Background and Aim

The prevalence of eosinophilic esophagitis (EoE) is rising in the West. However, data from the Indian subcontinent is limited. In this prospective cross-sectional study, we estimated the prevalence of EoE among children undergoing elective upper gastrointestinal endoscopy (UGIE).

Methods

We enrolled 200 consecutive children (123 boys, median age 10.25 years [interquartile range 8.25-14.5]) between March 2020 and November 2022 at our center. Clinical characteristics, endoscopic findings, and laboratory parameters were noted. A total of 12 mucosal biopsies (3 each from the middle and lower third of the esophagus, stomach, and duodenum) were obtained. EoE was diagnosed if the peak eosinophil count was ≥15/high-power field (HPF) in absence of gastric and duodenal eosinophilia.

Results

The commonest indications for UGIE were gastroesophageal reflux disease-like symptoms (29%), inflammatory bowel disease (22.5%), celiac disease (15%), and abdominal pain (13%). EoE was detected in seven children, suggesting an overall prevalence of 3.5%. Of the 20 children evaluated for dysphagia, 4 (20%) had EoE. Also, two of three (67%) children presented with food bolus impaction along with dysphagia had EoE. Of the seven children with EoE, three (43%) had bronchial asthma, two (28.5%) had peripheral eosinophilia, and one (14%) had elevated serum IgE. Trachealization and linear furrows were found in 57% and 71% cases, respectively. Four children received high-dose proton pump inhibitor (PPI) for 12 weeks, two received PPI+ stricture dilatation, and one received systemic steroids. All achieved clinical, endoscopic, and histopathological remission.

Conclusion

Hospital-based prevalence of EoE among children undergoing elective UGIE was 3.5%. EoE patients had favorable outcomes with PPI.

Global Incidence and Prevalence of Eosinophilic Esophagitis, 1976-2022: A Systematic Review and Meta-analysis

BACKGROUND AND AIMS

Owing to 2018 expanded diagnostic criteria for eosinophilic esophagitis (EoE) and thus a possible increase in diagnosis, previous studies on the global incidence and prevalence of EoE may need to be updated. We aimed to describe global, regional, and national trends in the incidence and prevalence of EoE from 1976 to 2022 and analyze their associations with geographic, demographic, and social factors through a systematic review.

METHODS

We searched the PubMed/MEDLINE, Embase, CINAHL, Google Scholar, and Cochrane databases from their inception dates to December 20, 2022, for studies that reported the incidence or prevalence of EoE in the general population. We calculated the global incidence and prevalence of EoE using pooled estimates with 95% confidence intervals (CIs) and performed subgroup analysis based on age, sex, race, geographical area, World Bank income group, and diagnostic criteria of EoE.

RESULTS

Forty studies met the eligibility criteria, including over 288 million participants and 147,668 patients with EoE from 15 countries across the five continents. The global pooled incidence and prevalence of EoE were 5.31 cases per 100,000 inhabitant-years (95% CI, 3.98-6.63; number of studies, 27; sample population, 42,191,506) and 40.04 cases per 100,000 inhabitant-years (95% CI, 31.10-48.98; number of studies, 20; sample population, 30,467,177), respectively. The pooled incidence of EoE was higher in high-income countries (vs low- or middle-income countries), males, and North America (vs Europe and Asia). The global prevalence of EoE followed a similar pattern. The pooled prevalence of EoE gradually increased from 1976 to 2022 (1976-2001; 8.18; 95% CI, 3.67-12.69 vs 2017-2022; 74.42; 95% CI, 39.66-109.19 cases per 100,000 inhabitant-years).

CONCLUSIONS

The incidence and prevalence of EoE have increased substantially and vary widely across the world. Further research is needed to evaluate the incidence and prevalence of EoE in Asia, South America, and Africa.

Clinical presentation and endoscopic findings in adult patients with eosinophilic esophagitis

Background/Aim: The frequency of eosinophilic esophagitis has been rising over the last decades. It is diagnosed primarily based on symptoms and endoscopic and histopathological examination findings. Although eosinophilic esophagitis is not associated with malignancy, it remains an important condition affecting both children and adults, as it is associated with morbidity such as dysphagia, food impaction, and esophageal strictures. This study aimed to define clinical and endoscopic characteristics of adult patients diagnosed with eosinophilic esophagitis based on recently recommended histopathological criteria. Methods: This retrospective cross-sectional descriptive study included 54 adult patients (mean age: 33.6 yr, range: 16–61 yr) who underwent upper gastrointestinal system endoscopy for dyspeptic complaints (epigastric pain, reflux, dysphagia, or food impaction) and diagnosed with eosinophilic esophagitis based on the latest histopathological criteria (≥15 eosinophils per high-power field). Patients with a history of malignancy were excluded. Patients’ clinical, endoscopic, and histopathological data were examined. Results: In patients diagnosed with eosinophilic esophagitis, the most common presenting complaint was dysphagia (61.1%), followed by dyspepsia (24.0%), regurgitation (16.6%), chest pain (16.6%), epigastric pain (12.9%), food impaction (11.1%), and halitosis (3.7%), without any age predilection for the complaints. White papules and linear furrow were the most frequent findings on endoscopic examination (35.1% each), followed by circular rings (24.0%), paleness (22.2%), normal endoscopic finding (20.3%), and small-caliber esophagus (11.1%). Conclusion: The diagnosis of eosinophilic esophagitis remains challenging due to considerable variations in definitions and in the relative frequencies of endoscopic findings. Therefore, we recommend combining clinical, endoscopic, and histologic criteria to establish diagnosis. The identification of standards for diagnosis in future studies is warranted.

Eosinophilic esophagitis-established facts and new horizons

Despite dramatic advances in our understanding of the pathogenesis and course of disease in the relatively short timeframe since the discovery and first description of eosinophilic esophagitis (EoE) less than three decades ago, many open questions remain to be elucidated. For instance, we will need to better characterize atypical clinical presentations of EoE and other forms of esophageal inflammatory conditions with often similar clinical presentations, nut fulfilling current diagnostic criteria for EoE and to determine their significance and interrelationship with genuine EoE. In addition, the interrelationship of EoE with other immune-mediated diseases remains to be clarified. Hopefully, a closer look at the role of environmental factors and their interaction with genetic susceptibility often in context of atopic predisposition may enable identifying the candidate substances/agents/allergens and potentially earlier (childhood) events to trigger the condition. It appears plausible to assume that in the end—comparable to current concepts in other immune-mediated chronic diseases, such as for instance inflammatory bowel disease or asthma bronchiale—we will not be rewarded with the identification of a “one-and-only” underlying pathogenetic trigger factor, with causal responsibility for the disease in each and every EoE patient. Rather, the relative contribution and importance of intrinsic susceptibility, i.e., patient-driven factors (genetics, aberrant immune response) and external trigger factors, such as food (or aero-) allergens as well as early childhood events (e.g., infection and exposure to antibiotics and other drugs) may substantially differ among given individuals with EoE. Accordingly, selection and treatment duration of medical therapy, success rates and extent of required restriction in dietary treatment, and the need for mechanical treatment to address strictures and stenosis require an individualized approach, tailored to each patient. With the advances of emerging treatment options, the importance of such an individualized and patient-centered assessment will increase even further.

How to approach adult patients with asymptomatic esophageal eosinophilia

As the awareness among gastroenterologists regarding endoscopic features suggesting eosinophilic esophagitis is increasing, individuals without symptoms of esophageal dysfunction are increasingly being found to have esophageal eosinophilia on biopsies performed during upper gastrointestinal endoscopies. However, the course of disease and the management of these asymptomatic individuals with esophageal eosinophilia remain elusive. In this review, we propose a definition of asymptomatic individuals with esophageal eosinophilia and discuss the prevalence, risk factors, and course of disease of this specific patient group. Furthermore, we have established a diagnostic and therapeutic pathway based on the most recent available data.

Reconsidering the "protective" hypothesis of Helicobacter pylori infection in eosinophilic esophagitis

Since its discovery, Helicobacter pylori (H. pylori) has attracted attention in the biomedical world with its numerous pathophysiologic implications, both gastrointestinal and systemic. Beyond its well-established carcinogenic properties, emerging evidence also supports "harmful" proinflammatory and neurodegenerative roles of H. pylori. On the other hand, H. pylori infection has been proposed to be "protective" against several diseases, such as asthma and gastroesophageal reflux disease. Eosinophilic esophagitis (EoE) is a relatively new, allergen/immune-mediated disease, which has also been linked to these considerations. Main arguments are a postulated shift of immune responses by H. pylori from T helper 2 (T_H 2) to T_H 1 polarization, as well as a potential decline of the H. pylori burden with the dramatic parallel rise of ΕοΕ: a series of observational studies reported an inverse association. In this review, we counter these arguments by providing further epidemiological data, which point out that this generalization might be rather incomplete. We also discuss the limitations of the existing studies evaluating a possible association. Furthermore, we provide current evidence on common pathogenetic components, which share both entities. In summary, the claim that H. pylori is protective against EoE is rather incomplete, and further mechanistic studies are necessary to elucidate a possible association.

Gastrointestinal involvement of primary skin diseases

Less is known about gastrointestinal (GI) involvement of primary skin diseases due to the difference in embryology, histology, microbiology and physiology between integument and alimentary tract. Oesophagus, following the oropharyngeal mucosa, is the most common GI segment affected by primary skin diseases, especially by eosinophilic oesophagitis, lichen planus and autoimmune bullous dermatoses like pemphigus vulgaris, mucosal membrane pemphigoid and epidermolysis bullosa acquisita. Eosinophilic oesophagitis is an emerging chronic atopic disease with oesophageal dysfunction as the typical presentation, and oesophageal narrowing, rings and stricture as late complications. Oesophageal lichen planus mainly involves the proximal to mid-oesophagus in elderly aged women with long-term oral mucosal lesions. In acute attack of pemphigus vulgaris, oesophageal involvement is not uncommon but often neglected and may cause sloughing oesophagitis (oesophagitis dissecans superficialis) with acute GI bleeding in rare cases. GI manifestation of hereditary bradykininergic angio-oedema with colicky acute abdomen mostly affects small intestine, usually in the absence of pruritus or urticaria, and is more severe and long-lasting than the acquired histaminergic form. Strong evidence supports association between inflammatory bowel disease, especially Crohn disease, and hidradenitis suppurativa/acne inversa. Patients with vitiligo need surveillance of autoimmune liver disease, autoimmune atrophic gastritis or coeliac disease when corresponding symptoms become suspect. Melanoma is the most common primary tumour metastatic to the GI tract, with small intestine predominantly targeted. Gastrointestinal involvement is not uncommon in disseminated mycosis fungoides. Extramammary Paget's disease is an intraepidermal adenocarcinoma of controversial origin, and a high association between the anogenital occurrence and colorectal adenocarcinoma has been reported. As GI tract is the largest organ system with multidimensional functions, dermatologists in daily practice should be aware of the gastrointestinal morbidities related to primary skin diseases for an early diagnosis and treatment.

Regional Differences in Food Allergies

The prevalence of food allergies is increasing worldwide. To understand the regional specificities of food allergies and develop effective therapeutic interventions, extensive regional epidemiological studies are necessary. While data regarding incidence, prevalence, regional variation, and treatment in food allergies are available for western countries, such studies may not be available in many Asian countries. China accounts for almost 20% of the world's population and has a vast ethnic diversity, but large-scale meta-analyses of epidemiological studies of food allergy in China are lacking. A literature search revealed 22 publications on the prevalence of food allergy in Chinese populations. A review of these studies showed that the prevalence of food allergies in China is comparable to that in western countries, even though the Chinese diet is vastly different from that of the West and may vary even greatly within China, and finally, specific antigenic triggers of food allergy vary between China and the West and also within China. Current clinical management of food allergy in China includes allergen-specific immunotherapy, Chinese herbal medicine, acupuncture, and Western medicine. This study demonstrates an unmet need in China for a thorough investigation of the prevalence of food allergies in China, the specific foods involved, and characterization of the specific antigenic triggers of food allergy with respect to ethnicity, age, and diet in China.

Risk of progression to eosinophilic esophagitis in patients with asymptomatic esophageal eosinophilia: A retrospective pilot study

Background and Aim

As the number of patients with eosinophilic esophagitis (EoE) has increased worldwide, the likelihood of diagnosing esophageal eosinophilia (EE) in screening endoscopy has also increased. Many of these EE patients do not display any symptoms (i.e. they display asymptomatic EE: aEE), and the risk of aEE patients developing EoE has yet to be demonstrated.

Methods

A total of 62 250 cases were found in the endoscopic registries of two digestive disease centers in the context of gastric cancer screening from April 2016 to August 2018, and these were reviewed.

Results

Thirty‐seven aEE patients (0.059%) were found in the registries, and the histories of endoscopic findings and symptoms were successfully traced for 29 of them. While 11 aEE (37.9%) patients did not show any change in endoscopic findings, 18 (62.1%) exhibited exacerbation. A comparison of the two groups showed both relative youth and diffuse disease distribution to be independent risk factors for progression (P = 0.0034 and 0.0078, respectively). Of the 18 aEE patients whose findings showed progression, 6 developed EoE (5 (17.2%) developed proton‐pump inhibitor (PPI)‐responsive EoE, and only 1 (3.4%) developed PPI‐resistant EoE). A comparison of the non‐EoE and EoE groups showed relative youth to be an independent risk factor for progression to EoE (P = 0.0146).

Conclusions

While some aEE patients developed symptomatic EE, the existence among them of PPI‐resistant EoE was extremely rare. Younger age and diffuse disease distribution at first detection in endoscopic findings are risk factors for progression to symptomatic EE in aEE patients.

Association Between Helicobacter pylori Exposure and Decreased Odds of Eosinophilic Esophagitis-A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Previous or current infection with Helicobacter pylori (exposure) has been reported to protect against eosinophilic esophagitis (EoE), perhaps owing to H pylori-induced immunomodulation. However, findings vary. We performed a systematic review and meta-analysis of comparative studies to define the association between H pylori exposure and EoE more clearly.

METHODS

We searched 4 large databases to identify comparative clinical studies that included sufficient detail to determine the odds or risk of EoE (primary outcome) or esophageal eosinophilia (secondary outcome) among individuals exposed to H pylori (exposed) vs individuals who were tested and found to be unexposed. Estimates were pooled using a random-effects model. Meta-regression and sensitivity analyses were planned a priori. Studies were evaluated for quality, risk of bias, publication bias, and heterogeneity.

RESULTS

We analyzed 11 observational studies comprising data on 377,795 individuals worldwide. H pylori exposure vs nonexposure was associated with a 37% reduction in odds of EoE (odds ratio, 0.63; 95% CI, 0.51-0.78) and a 38% reduction in odds of esophageal eosinophilia (odds ratio, 0.62; 95% CI, 0.52-0.76). Fewer prospective studies found a significant association between H pylori exposure and EoE (P = .06) than retrospective studies. Effect estimates were not affected by study location, whether the studies were performed in pediatric or adult populations, time period (before vs after 2007), or prevalence of H pylori in the study population.

CONCLUSIONS

In a comprehensive meta-analysis, we found evidence for a significant association between H pylori exposure and reduced odds of EoE. Studies are needed to determine the mechanisms of this association.

Obesity and hiatal hernia may be non-allergic risk factors for esophageal eosinophilia in Japanese adults

BACKGROUND

Esophageal eosinophilia (EE) is a basal condition of eosinophilic esophageal disorders including eosinophilic esophagitis (EoE) and asymptomatic EE. EoE is considered as an allergic disorder, while it is unclear whether other non-allergic conditions are involved in the pathophysiology of EE. The aim of this study is to investigate the non-allergic risk factors for EE.

METHODS

This cross-sectional study included subjects who underwent esophagogastroduodenoscopy on a medical health check-up. We compared clinical characteristics between subjects with EE (n = 27) and those without EE (n = 5937).

RESULTS

The detection rate of EE was 0.45% (27/5964 persons). Of 27 subjects with EE, 20 subjects were symptomatic and 7 were asymptomatic. On univariate analysis, subjects with EE significantly had higher body mass index (BMI) compared to those without EE; 23.4 (4.4) vs 22.3 (4.5) kg/m², median (interquartile range), p = 0.005. Endoscopic findings revealed that subjects with EE had significantly higher proportion of hiatal hernia (29.6% vs 14.7%; p = 0.049). Subjects with EE were significantly younger and had higher proportion of bronchial asthma; 45 (11.5) vs 51 (18) years, p = 0.013; 25.9% vs 5.2%, p < 0.001, respectively. Multivariate analysis showed that subjects with EE were positively associated with BMI [odds ratio (OR) 1.11; 95% confidence interval (CI) 1.03-1.20; p = 0.010) and hiatal hernia (OR 2.63; 95% CI 1.12-6.18; p = 0.026) compared to those without EE. On trend test, advanced BMI classification had significant trend for increased prevalence of EE (p = 0.002).

CONCLUSIONS

Obesity and hiatal hernia may be non-allergic risk factors for EE in Japanese adults.

Association between endoscopic findings of eosinophilic esophagitis and responsiveness to proton pump inhibitors

Background and study aims  Endoscopic findings of esophageal eosinophilia sometimes localize to small areas of the esophagus. A previous study suggested that pathogenesis of localized-type eosinophilic esophagitis (LEoE) was associated with acid reflux. However, LEoE treatment outcomes have not been studied. We aimed to analyze the clinical and histologic significance of LEoE in comparison with diffuse-type eosinophilic esophagitis (DEoE). Patients and methods  This study included 106 patients with esophageal eosinophilia. Esophageal eosinophilia was defined as a condition where the maximum number of intraepithelial eosinophils was ≥ 15 per high-power field. LEoE was defined as an endoscopic lesion confined to one-third of the esophagus: upper, middle, or lower. Esophageal eosinophilia encompassing more than two-thirds of the esophagus was defined as DEoE. We retrospectively compared LEoE and DEoE in terms of clinical characteristics, histologic findings, and proportion of proton pump inhibitor (PPI) responders. Results  Of 106 patients, 12 were classified as having LEoE and 94 were classified as having DEoE. The proportion of asymptomatic patients was significantly higher in the LEoE group than the DEoE group (42 % vs 7 %, P  < 0.01). In the LEoE group, 10 patients (84 %) had endoscopic lesions in the lower esophagus. The maximum number of eosinophils did not differ between the groups (54 [24 - 71] for LEoE, 40 [20 - 75] for DEoE, P  = 0.65). The prevalence of PPI responders was significantly higher in the LEoE group than the DEoE group (100 % vs 63 %, P  = 0.01). Conclusion  LEoE can be a sign of good responsiveness to PPI therapy.

Epidemiology and Natural History of Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) has emerged over the past 2 decades as a major cause of upper gastrointestinal morbidity. Over this time, the epidemiology of EoE has also rapidly evolved. EoE has transformed from a rare case-reportable condition to disease that is commonly encountered in the gastroenterology clinic, hospital emergency room, and endoscopy suite. The incidence and prevalence are increasing at rates that outpace increased disease recognition. Current incidence estimates range from 5 to 10 cases per 100,000, and current prevalence estimates range from 0.5 to 1 case per 1000. We review the data and potential reasons behind this increase, examine risk factors, and identify important areas for research into disease etiology. The article also discusses the progression of EoE from an inflammatory to fibrostenotic phenotype. An accurate view of the natural history of EoE is central to discussions with patients regarding disease prognosis and decisions about long-term use of medical, endoscopic, and diet therapies. Progressive remodelling appears to be gradual, but not universal, and the duration of untreated disease is the best predictor of stricture risk. Ultimately, prospective, long-term outcome studies focusing on multiple aspects of disease activity are needed to fully understand the natural history of EoE.

Demographic Features of Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is an increasingly prevalent chronic condition characterized by eosinophilic infiltration of the esophageal epithelium accompanied by esophageal symptoms. The number of new diagnoses is growing worldwide in both pediatric and adult populations. Differences in disease distribution and presentation have been found, varying by gender, race, and other characteristics. This review examines the existing literature and provides insight into the demographic features of EoE.

Eosinophilic esophagitis. The North against the South? A bio-economic-social mechanistic approach and clinical implications

Eosinophilic esophagitis is a chronic antigen-mediated disease characterized by esophageal symptoms, esophageal eosinophilia, and the absence of response to proton pump inhibitors. It is the most frequent cause of dysphagia and food impaction in adults. Its incidence and prevalence is very high in the developed countries (USA, Europe, Australia), where its connotation is that of an emerging epidemic. While studies have been published with large case series in the developed countries, those published in Latin America are small or consist of isolated case reports. The differences in the prevalence of the disease between the developed and developing regions are unknown. Genetic or racial causes have been cited. Nevertheless, the epidemic nature of the disease suggests that environmental causes are the most powerful. Based on the published hypotheses, as well as on epidemiologic studies, the present review discusses some of the possible causes of the disparity in the prevalence of eosinophilic esophagitis between the two types of countries. The 'hygiene hypothesis' is reviewed, together with the possible relation of Helicobacter pylori, intestinal parasites, and modifications of the esophageal microbiota in patients with eosinophilic esophagitis. In reference to studies conducted in the United States, the clinical behavior and progression of eosinophilic esophagitis in Hispanics is reviewed and a possible predominant phenotype in Mexican and other Latin American patients is discussed. Finally, based on the above, an algorithm for studying the disease in the Latin American countries is proposed.

Eosinophilic Esophagitis From an Allergy Perspective: How to Optimally Pursue Allergy Testing & Dietary Modification in the Adult Population

Eosinophilic esophagitis (EoE) is a clinicopathologic condition characterized by symptoms of esophageal dysfunction and eosinophil-predominant inflammation. In adults, the three most common treatment options are swallowed steroids, elimination diets, and periodic esophageal dilations. Many different elimination diets have been studied in adults, including elemental diets, allergy testing-directed diets, and empiric elimination diets. This article will review the existing data on these dietary therapies and will propose an approach to dietary management in adult EoE.

Lack of compliance with consensus recommendations on the diagnosis of eosinophilic esophagitis (EoE) in published prevalence studies. A clinical and systematic review

OBJECTIVE

According to consensus recommendations, the presence of esophageal symptoms, >15 eosinophils/high-power field and unresponsiveness to proton pump inhibitors are required for a diagnosis of eosinophilic esophagitis (EoE). Nevertheless, inconsistency in using these guidelines has been reported in recent publications. The objective of this study was to assess compliance with EoE diagnostic guidelines in published studies on EoE prevalence and to evaluate other clinical and methodological parameters.

METHODS

A systematic review was conducted in articles published between 2008 and 2015 on the prevalence of EoE in unselected adults. Studies using EoE diagnostic definitions were judged to be compliant if they included all three components of the definition, partially compliant if they included two and non-compliant if they included one or none. Esophageal biopsy protocol differences and descriptions of patients' characteristics were determined.

RESULTS

Among the 20 studies included, eight were performed in a hospital setting and 12 in the general population. Only 40.0% of studies were compliant, 35.0% were partially compliant and 25.0% were non-compliant with the EoE diagnostic definition guidelines. In 60.0% of the studies a proton pump inhibitor trial was not administered. Only 30.0% adhered to the recommendations in the esophageal biopsy protocol. A lack of description of the history of atopia and endoscopic characteristics was observed in many studies.

CONCLUSIONS

Partial or non-compliance with the EoE diagnostic definition was observed in most of the published prevalence studies after the publication of the first consensus. The results of these studies might be interpreted taking into account this context.

Meta-Analysis-Based Guidance for Dietary Management in Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is a prevalent chronic esophageal disorder, triggered and maintained by immunologically mediated responses against dietary antigens. EoE represents the most recent form of food allergy, and its control by avoiding offending foods has increasingly appeared as a therapeutic alternative to achieve and maintain remission. Dietary therapies have proved equally effective in pediatric and adult EoE patients, among whom various types of interventions to eliminate or reduce food antigens exposure have been evaluated. A recent meta-analysis showed elemental diet as the most effective option to induce disease remission, but with a limited application in clinical practice. Inconsistency and wide variability in results from skin allergy testing-directed food restriction contributed to dissatisfaction with implementation of this option, which subsequently was displaced by empiric elimination of common food allergens. Such empiric elimination of common food allergens is now recognized as the best alternative for dietary treatment, with moderate-to-high efficiency and reproducible results. This review provides evidence-based insights into the dietary management of EoE.

Systematic review with meta-analysis: the incidence and prevalence of eosinophilic oesophagitis in children and adults in population-based studies

BACKGROUND

The recognition of eosinophilic oesophagitis (EoE) has risen sharply, but its current epidemiology is still under debate.

AIM

To estimate accurately the prevalence and incidence rates of EoE, by a systematic review and meta-analysis.

METHODS

MEDLINE, EMBASE and SCOPUS databases were searched for population-based studies on the epidemiology of EoE. Pooled incidence and prevalence rates, male:female and children:adult ratios, and geographical and temporal variations were calculated with random-effects models.

RESULTS

The search yielded 1334 references; the final quantitative summary included 13 population-based studies from North America, Europe and Australia, with the results showing high heterogeneity. The pooled EoE incidence rate was 3.7/100 000 persons/year [95% confidence interval (CI): 1.7-6.5] and was higher for adults (7; 95% CI: 1-18.3) than for children (5.1; 95% CI: 1.5-10.9). The pooled prevalence of EoE was 22.7 cases/100 000 inhabitants (95% CI: 12.4-36), rising to 28.1 (95% CI: 13-49) when studies with a lower risk of bias were considered; prevalence was higher in adults than in children (43.4; 95% CI: 22.5-71.2 vs. 29.5; 95% CI: 17.5-44.7, respectively), and in American compared to European studies. A steady rise in EoE incidence and prevalence rates was observed upon comparison of studies conducted before and after 2008. No significant publication bias was found.

CONCLUSIONS

Eosinophilic oesophagitis is an increasingly common diagnosis in North America and Europe. The population-based incidence and prevalence of eosinophilic oesophagitis vary widely across individual studies, probably due to variations in diagnosis and risk of bias of research. More prospective, large-scale, multicenter studies are needed to evaluate reported data.