Seasonal exacerbation of esophageal eosinophilia in children with eosinophilic esophagitis and allergic rhinitis

Allergen immunotherapy and eosinophilic esophagitis: friends or foes?

PURPOSE OF REVIEW

The connection between eosinophilic esophagitis (EoE) and food and airborne allergens is complex. Exposure to allergens (mainly food) is often the trigger for EoE flares. The development of EoE has been described as a side effect of allergen immunotherapy, especially oral immunotherapy (OIT, with food allergens), while isolated cases of EoE have been reported during sublingual immunotherapy (SLIT, with extracts of aeroallergens).

RECENT FINDINGS

EoE is currently recognized as a common side effect of OIT, while a solid correlation between SLIT and EoE is missing. Animal models have been developed to study the pathophysiological link between sensitization to aeroallergens and the induction of EoE and will probably provide an interpretation of why there are cases of EoE developed during SLIT. Recent findings in animal models suggest a genetic connection to EoE development after sensitization and re-exposure to airborne allergens. Subcutaneous allergen immunotherapy does not have a causative effect on EoE; on the contrary, a beneficial effect on EoE has been reported. Moreover, epicutaneous immunotherapy with a vector containing milk has also been used to treat children with milk-induced EoE.

SUMMARY

Discovering the immune links between allergens and EoE will further guide the proper use of allergen immunotherapy and help define future strategies for the management of EoE.

Associations of Eosinophilic Gastrointestinal Disorders with Other Gastrointestinal and Allergic Diseases

Eosinophilic gastrointestinal disorders (EGIDs) are becoming more common causing significant suffering and reduced quality of life. These conditions can affect different parts of the digestive system, either individually or in combination. Recognition of their link to allergic disorders or other gastrointestinal (GI) diseases has raised questions about their shared underlying mechanisms, which has had implications for diagnosis and management. The authors critically examine the current understanding of the connection between EGIDs and allergic conditions (ie, atopic dermatitis, allergic rhinitis, asthma, and food allergy) and GI diseases (ie, inflammatory bowel disease, celiac disease, gastroesophageal reflux disease, and motility disorders).

The Relationship Between Eosinophilic Esophagitis and Immunotherapy

Immunotherapy is a treatment approach based on the principle of incremental allergen exposure to achieve desensitization. Recently, oral immunotherapy has been introduced as a treatment of IgE-mediated food allergy. Some patients receiving oral immunotherapy for food allergy may develop eosinophilic esophagitis. Here, we summarize the literature examining this association, its treatment, and outcomes and discuss possible explanations for this clinical phenomenon. We further identify potential associations with aeroallergen sensitivity and other forms of immunotherapy including subcutaneous immunotherapy and sublingual immunotherapy. Finally, we discuss management of immunotherapy-induced eosinophilic esophagitis. Epicutaneous immunotherapy is highlighted as an area of therapeutic investigation.

Clinical Evaluation of the Child with Eosinophilic Esophagitis

The diagnosis of eosinophilic esophagitis (EoE) is based on clinical symptoms of esophageal dysfunction and eosinophil predominant esophageal inflammation. Clinical symptoms in children with EoE vary based on age and may be nonspecific. EoE has a male predominance with the majority having comorbid atopic disorders. At present, treatment options include medications (proton pump inhibition, swallowed topical steroids), dietary therapy or biologic therapy (dupilumab, approved for those ≥12 years of age). Outside of EoE in the context of oral immunotherapy, EoE is typically chronic requiring lifelong therapy. Long-term complications including feeding difficulties, malnutrition, and fibrostenotic disease.

Allergic phenotype identified on allergen testing is associated with proton pump inhibitor nonresponse in eosinophilic esophagitis

BACKGROUND AND AIM

Food/environmental allergens have been associated with eosinophilic esophagitis (EoE); however, the correlation between allergy profiles and disease responsiveness to proton pump inhibitor (PPI) therapy remains unclear. We aimed to assess the association between food/environmental allergies identified on allergen testing and histologic response to PPI in patients with treatment-naive EoE.

METHODS

Adults with newly diagnosed EoE who underwent formal testing for food/environmental allergies at a tertiary center were included. All patients underwent twice-daily PPI for 8 weeks with subsequent repeat endoscopy and biopsy to assess histologic response. Patients with <15 eosinophils/hpf on post-PPI mucosal biopsies were classified as responders (PPI-r-EoE), while those with ≥15 eosinophils/hpf were nonresponders (PPI-nr-EoE).

RESULTS

Sixty-one patients met inclusion criteria (21 PPI-r-EoE vs 40 PPI-nr-EoE). Demographic, clinical, and endoscopic finding variables were similar between groups. Positive food allergen test was more prevalent among PPI-nr-EoE patients (82.5% vs 42.9%, P = 0.003). On multivariable analysis, positive food allergen testing remained an independent predictor for PPI nonresponse (aOR 0.15, CI: 0.04-0.58, P = 0.0006). Positive environmental allergen testing was highly prevalent, with no significant differences between groups (77.5% vs 95.2%, P = 0.14). However, higher number of positive environmental allergens (23.3% [≥5 allergens] vs 73.3% [<5 allergens], P = 0.003) and specific aeroallergens correlated with PPI-nr-EoE.

CONCLUSION

Positive food allergy testing and increased environmental allergens predicted lower likelihood of histologic response to PPI in EoE. Our findings support an allergic phenotype of EoE that may less likely respond to PPI therapy. Formal allergen testing may play a role in therapy selection and tailored management in EoE.

Assessment of the Severity and the Remission Criteria in Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is an immune-mediated disease that manifests with dysphagia and is characterized by the predominantly eosinophilic infiltration of the esophageal mucosa. Several instruments have been developed to assess the symptoms of EoE: the Daily Symptom Questionnaire (DSQ), EoE Activity Index (EEsAI), Pediatric EoE Symptom Severity (PEESSv2), etc. The use of the EREFS is a gold standard for endoscopic diagnosis. The EoE histologic scoring system (EoEHSS) was elaborated for the assessment of histological features in EoE. However, the remission criteria are not clearly defined and vary greatly in different studies. Gastroenterologists establish the severity of EoE mainly based on endoscopic findings. At the same time, EoE requires a multidisciplinary approach. The recently developed Index of Severity of Eosinophilic Esophagitis (I-SEE) that is built on symptoms, endoscopic findings, and histological features is promising.

A case of food and aeroallergen sublingual immunotherapy inducing eosinophilic esophagitis

Eosinophilic esophagitis (EoE) has been reported secondary to aeroallergen sublingual immunotherapy (SLIT) and food allergen oral immunotherapy. Gastrointestinal symptoms with food allergen SLIT are uncommon, with no prior reports of cases of food allergen SLIT inducing EoE. Here we report a patient who developed EoE secondary to food and aeroallergen SLIT therapy that resolved with SLIT cessation.

Eosinophilic esophagitis patients with multiple atopic conditions: Clinical characteristics and treatment response to topical steroids

BACKGROUND

Patients with eosinophilic esophagitis (EoE) typically have concomitant atopic conditions, but whether there are differences in presentation or treatment response by the number of atopic diseases is unknown.

OBJECTIVE

To determine whether patients with EoE having multiple atopic conditions have differences in presentation or response to topical corticosteroid (TCS) treatment.

METHODS

We performed a retrospective cohort study of adults and children with newly diagnosed EoE. The total number of atopic comorbidities (allergic rhinitis, asthma, eczema, food allergy) was calculated. Patients with at least 2 atopic conditions other than allergic rhinitis were defined as having multiple atopic conditions and their baseline characteristics were compared with those with less than 2 atopic conditions. Histologic, symptom, and endoscopic responses to TCS treatment were also compared with bivariable and multivariable analyses.

RESULTS

Of the 1020 patients with EoE having atopic disease information, 235 (23%) had 1 atopic comorbidity, 211 (21%) had 2, 113 (11%) had 3, and 34 (3%) had 4. At baseline, the 180 (18%) patients with 2 or more atopic diseases were younger and had more vomiting, less abdominal pain, more exudates and edema on endoscopy, and higher peak eosinophil counts. Among those treated with TCS, there was a trend toward better global symptom response in patients with less than 2 atopic conditions, but there was no difference in histologic or endoscopic response compared with those with 2 or more atopic conditions.

CONCLUSION

There were differences in the initial presentation of EoE between those with and without multiple atopic conditions, but there were no major differences in histologic treatment response to corticosteroids by atopic status.

Development of a Practical Guide to Implement and Monitor Diet Therapy for Eosinophilic Esophagitis

Dietary therapy for short- and long-term management of eosinophilic esophagitis is an effective yet poorly understood and underutilized treatment strategy. Despite several prospective trials demonstrating the efficacy of dietary therapies, successful clinical implementation is hampered by the need for a multidisciplinary approach including dietitian support and provider expertise. The availability of these resources is not readily available to most gastroenterologists. Without standardized guidance on starting or completing the diet for gastrointestinal providers and/or consulting dietitians, provider attitudes toward dietary therapy vary greatly depending on familiarity and knowledge gaps in using diet therapy. This review aims to summarize evidence in support of dietary therapy in eosinophilic esophagitis while providing guidance on initiation and implementation of dietary therapy for providers.

International consensus statement on allergy and rhinology: Allergic rhinitis - 2023

BACKGROUND

In the 5 years that have passed since the publication of the 2018 International Consensus Statement on Allergy and Rhinology: Allergic Rhinitis (ICAR-Allergic Rhinitis 2018), the literature has expanded substantially. The ICAR-Allergic Rhinitis 2023 update presents 144 individual topics on allergic rhinitis (AR), expanded by over 40 topics from the 2018 document. Originally presented topics from 2018 have also been reviewed and updated. The executive summary highlights key evidence-based findings and recommendation from the full document.

METHODS

ICAR-Allergic Rhinitis 2023 employed established evidence-based review with recommendation (EBRR) methodology to individually evaluate each topic. Stepwise iterative peer review and consensus was performed for each topic. The final document was then collated and includes the results of this work.

RESULTS

ICAR-Allergic Rhinitis 2023 includes 10 major content areas and 144 individual topics related to AR. For a substantial proportion of topics included, an aggregate grade of evidence is presented, which is determined by collating the levels of evidence for each available study identified in the literature. For topics in which a diagnostic or therapeutic intervention is considered, a recommendation summary is presented, which considers the aggregate grade of evidence, benefit, harm, and cost.

CONCLUSION

The ICAR-Allergic Rhinitis 2023 update provides a comprehensive evaluation of AR and the currently available evidence. It is this evidence that contributes to our current knowledge base and recommendations for patient evaluation and treatment.

Allergen-free extracts from birch, ragweed, and hazel pollen activate human and guinea-pig submucous and spinal sensory neurons

BACKGROUND

Non-allergenic, low molecular weight components of pollen grains are suspected to trigger changes in gut functions, sometimes leading to inflammatory conditions. Based on extensive neuroimmune communication in the gut wall, we investigated the effects of aqueous pollen extracts (APE) on enteric and spinal sensory neurons.

METHODS

Using Ca²⁺ and fast potentiometric imaging, we recorded the responses of guinea-pig and human submucous and guinea-pig dorsal root ganglion (DRG) neurons to microejection of low (<3 kDa) and high (≥3 kDa) molecular weight APEs of birch, ragweed, and hazel. Histamine was determined pharmacologically and by mass spectrometry (LC-MS/MS).

KEY RESULTS

Birch APE_<3kDa evoked strong [Ca⁺² ]_i signals in the vast majority of guinea-pig DRG neurons, and in guinea-pig and human enteric neurons. The effect of birch APE_≥3kDa was much weaker. Fast neuroimaging in human enteric neurons revealed an instantaneous spike discharge after microejection of birch, ragweed, and hazel APE_<3kDa [median (interquartile range) at 7.0 Hz (6.2/9.8), 5.7 Hz (4.4/7.1), and 8.4 Hz (4.3/12.5), respectively]. The percentage of responding neurons per ganglion were similar [birch 40.0% (33.3/100.0), ragweed 50.8% (34.4/85.6), and hazel 83.3% (57.1/100.0)]. A mixture of histamine receptor (H1-H3) blockers significantly reduced nerve activation evoked by birch and ragweed APEs_<3kDa , but was ineffective on hazel. Histamine concentrations in ragweed, birch and hazel APE's < 3 kDa were 0.764, 0.047, and 0.013 μM, respectively.

CONCLUSIONS

Allergen-free APEs from birch, ragweed, and hazel evoked strong nerve activation. Altered nerve-immune signaling as a result of severe pollen exposure could be a pathophysiological feature of allergic and non-allergic gut inflammation.

Breaking down the complex pathophysiology of eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a chronic and progressive immune-mediated disease of the esophagus associated with antigen-driven type 2 inflammation and symptoms of esophageal dysfunction. Our understanding of EoE pathophysiology has evolved since its initial recognition more than 20 years ago and has translated into diagnostic and novel therapeutic approaches that are affecting patient care. The mechanisms underlying disease development and progression are influenced by diverse factors, such as genetics, age, allergic comorbidities, and allergen exposures. Central to EoE pathophysiology is a dysregulated feed-forward cycle that develops between the esophageal epithelium and the immune system. Allergen-induced, type 2-biased immune activation by the esophageal epithelium propagates a cycle of impaired mucosal barrier integrity and allergic inflammation, eventually leading to tissue remodeling and progressive organ dysfunction. Herein, we review the current understanding of fundamental pathophysiological mechanisms contributing to EoE pathogenesis.

Nature with Nurture: the Role of Intrinsic Genetic and Extrinsic Environmental Factors on Eosinophilic Esophagitis

PURPOSE OF REVIEW

As the rising prevalence and incidence of eosinophilic esophagitis (EoE) has quickly outpaced the rate of esophageal biopsies, particularly in Westernized countries, several studies have suggested a link between intrinsic genetic and extrinsic environmental risk factors and the development, presentation, and diagnosis of EoE. This review aims to critically assess existing studies describing the role of the environment on the development, symptomatic presentation, and diagnosis of this recently recognized chronic immune-mediated disease.

RECENT FINDINGS

We present and critically evaluate the working hypotheses and supportive studies thus far on environmental factors on EoE, describe sources of potential bias in diagnosis due to socioeconomic factors and thus undermining studies of EoE etiology, and highlight opportunities for future research. As genetics alone do not explain the rapid rise of EoE, we must look to environmental, or extrinsic, factors both in the early-life period which shape the development of the gut microbiome, as well as later life contributing to diagnosis of this new disease. Future etiologic studies linking risk factors to EoE development in individual patients are needed.

Allergy-Test-Based Elimination Diets for the Treatment of Eosinophilic Esophagitis: A Systematic Review of Their Efficacy

Eosinophilic esophagitis (EoE) is an immune-mediated esophageal disorder, linked with sensitization to food and airborne allergens. Dietary manipulations are proposed for the management of EoE inflammation and are often successful, confirming the etiological role of food allergens. Three different dietary approaches are widely used: the elemental, the empirical, and the allergy-test-driven approach. We performed a systematic review to assess the evidence on the association of allergens, detected by allergy tests, with clinically confirmed triggers of EoE. We systematically searched PubMed, Scopus, Embase, and the Cochrane Library, through 1 June 2021. We sought studies examining the correlation of skin-prick tests (SPT), atopy patch tests (APT), specific IgE, and serum-specific IgG4, with confirmed triggers of EoE. Data on the use of prick–prick tests were also extracted. Evidence was independently screened by two authors against predefined eligibility criteria. Risk of bias was assessed with the ROBINS-I tool. Of 52 potentially eligible studies, 16 studies fulfilling quality criteria were included. These studies used one to three different allergy tests detecting food sensitization. The positive predictive value was generally low to moderate but higher when a combination of tests was used than single-test evaluations. None of the selected studies used serum-specific IgG4. Although an extreme methodological variability was noticed in the studies, allergy-based elimination diets were estimated to be efficient in 66.7% of the cases. The efficacy of targeted elimination diets, guided by SPT, sIgE, and/or APT allergy tests, does not appear superior to empirical ones. In the future, tests using esophageal prick testing or ex vivo food antigen stimulation may prove more efficient to guide elimination diets.

Type 2 Inflammation in Eosinophilic Esophagitis: From Pathophysiology to Therapeutic Targets

Eosinophilic esophagitis (EoE) is a chronic immune-mediated disease of the esophagus characterized clinically by symptoms related to esophageal dysfunction and histologically by eosinophil-predominant inflammation, whose incidence is rising. It significantly affects patients’ quality of life and, if left untreated, results in fibrotic complications. Although broad consensus has been achieved on first-line therapy, a subset of patients remains non-responder to standard therapy. The pathogenesis of EoE is multifactorial and results from the complex, still mostly undefined, interaction between genetics and intrinsic factors, environment, and antigenic stimuli. A deep understanding of the pathophysiology of this disease is pivotal for the development of new therapies. This review provides a comprehensive description of the pathophysiology of EoE, starting from major pathogenic mechanisms (genetics, type 2 inflammation, epithelial barrier dysfunction, gastroesophageal reflux, allergens, infections and microbiota) and subsequently focusing on the single protagonists of type 2 inflammation (involved cells, cytokines, soluble effectors, surface proteins and transcription factors) that could represent present and future therapeutic targets, while summarizing previous therapeutic approaches in literature.

Eosinophilic esophagitis in children: Updates and practical aspects of management for allergists in a non-tertiary care private practice setup

Background: Eosinophilic esophagitis (EoE) is a chronic immune and/or antigen-mediated disease characterized by eosinophilic infiltration of mucosa (≥15 eosinophils per high power field) without any secondary etiology. Non-immunoglobulin E mediated mechanisms predominate in EoE. Objective: This review concentrated on a stepwise approach for the allergist working in non-tertiary care private practice. Methods: A medical literature search that focused on several areas of the latest developments in the diagnosis and management of EoE was conducted. Results: There has been a steady increase in the prevalence and incidence of EoE. Clinical symptoms can vary from dysphagia to failure to thrive, depending on the age at presentation; some children develop adaptive behaviors to compensate for dysphagia, such as food preferences and slow eating. The diagnosis is based on a high index of clinical suspicion and is confirmed with endoscopy with biopsies after ruling out other causes of esophageal eosinophilia. Treatment options may include dietary therapy, pharmacologic therapies, or combination therapy. Therapeutic options may also include endoscopic dilation for stricturing disease. Conclusion: Providers should be aware of recent recommendation changes in the diagnostic workup, the role of skin-prick testing, and role of the proton-pump inhibitor as first-line therapy for EoE. Also, clinicians should be aware of the emerging role of empiric dietary therapy as a preferable therapeutic option when compared with the testing-directed diet and the elemental diet. Furthermore, topical glucocorticoid therapies are available, and new developing therapies are being investigated. Reevaluation of esophageal mucosa with biopsies is required approximately 2 months after therapy for a response and after a change in therapies to confirm continued resolution.

Viral Induced Effects on a Vulnerable Epithelium; Lessons Learned From Paediatric Asthma and Eosinophilic Oesophagitis

The epithelium is integral to the protection of many different biological systems and for the maintenance of biochemical homeostasis. Emerging evidence suggests that particular children have epithelial vulnerabilities leading to dysregulated barrier function and integrity, that resultantly contributes to disease pathogenesis. These epithelial vulnerabilities likely develop in utero or in early life due to various genetic, epigenetic and environmental factors. Although various epithelia are uniquely structured with specific function, prevalent allergic-type epithelial diseases in children potentially have common or parallel disease processes. These include inflammation and immune response dysregulation stemming from atypical epithelial barrier function and integrity. Two diseases where aetiology and pathogenesis are potentially linked to epithelial vulnerabilities include Paediatric Asthma and Eosinophilic Oesophagitis (EoE). For example, rhinovirus C (RV-C) is a known risk factor for paediatric asthma development and is known to disrupt respiratory epithelial barrier function causing acute inflammation. In addition, EoE, a prevalent atopic condition of the oesophageal epithelium, is characterised by similar innate immune and epithelial responses to viral injury. This review examines the current literature and identifies the gaps in the field defining viral-induced effects on a vulnerable respiratory epithelium and resulting chronic inflammation, drawing from knowledge generated in acute wheezing illness, paediatric asthma and EoE. Besides highlighting the importance of epithelial structure and barrier function in allergic disease pathogenesis regardless of specific epithelial sub-types, this review focuses on the importance of examining other parallel allergic-type disease processes that may uncover commonalities driving disease pathogenesis. This in turn may be beneficial in the development of common therapeutics for current clinical management and disease prevention in the future.

The Challenges of Managing Multiple Food Allergies and Consequent Food Aversions

The allergic march can often result in children with one food allergy phenotype developing other allergic manifestations as they grow older. In this grand round, we describe the case of a child with a diagnosis of eosinophilic esophagitis at an early age, who subsequently developed IgE-mediated allergy to milk and egg. Because of the onset of allergic rhinitis, an additional complication of the teenage years was the development of pollen food syndrome, which further affected the already complex dietary management. These multiple allergies had a consequent effect on nutritional status and provoked considerable psychosocial issues, which greatly affected the patient's relationship with food. This case illustrates that for complex patients, a cohesive approach and shared decision-making are essential for diagnosis and management. Working with the patient and also the whole family, and considering how best to support them, necessitates a flexible approach. Regular follow-up is important to address changing psychosocial and dietary needs and monitor the resolution of allergies and response to pharmacotherapy. Complex patients need the input of a comprehensive multidisciplinary team, with good access to dietetic and psychological support, to optimize quality of life for these individuals and their families.

Eosinophilic Esophagitis

Eosinophilic esophagitis is a recently defined condition that has dramatically increased in prevalence in the last several decades. It may occur at any age, but the clinical presentation in young children is often more vague than the classic solid food dysphagia and food impacting that are the major presenting symptoms of eosinophilic esophagitis in adults and adolescents. Successful therapies exist, including medications and dietary modifications, but disease typically recurs when the intervention is discontinued.

The Role of the Environment in Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is a chronic immune-mediated disease clinicopathologically characterized by esophageal dysfunction. EoE is characterized by eosinophilic histologic inflammation indistinguishable from other atopic diseases such as asthma, eczema, or allergic rhinitis, which often co-occur in patients with EoE. This suggest a possible shared pathophysiology and triggers in the development of EoE with other atopic conditions. Although the evidence of EoE being linked to exposure to allergenic foods is strong, the connection between EoE and aeroallergens is less understood. In this review, we will discuss clinical, epidemiological, and animal studies that investigate how environmental allergens influence the clinical manifestations of EoE and its seasonality. It is also known that the developing immune system is significantly shaped by early-life exposures, pollution, climate change, and those factors that are known to influence development of asthma. We therefore also describe the evidence for and the gaps in our knowledge of the role of early-life exposures, pollution, and climate change in the development of EoE.

Eosinophilic gastrointestinal disorders and allergen immunotherapy: Lights and shadows

Allergic diseases, such as IgE-mediated food allergy, asthma, and allergic rhinitis, are relevant health problems worldwide and show an increasing prevalence. Therapies for food allergies are food avoidance and the prompt administration of intramuscular epinephrine in anaphylaxis occurring after accidental exposure. However, allergen immunotherapy (AIT) is being investigated as a new potential tool for treating severe food allergies. Effective oral immunotherapy (OIT) and epicutaneous immunotherapy (EPIT) induce desensitization and restore immune tolerance to the causal allergen. While immediate side effects are well known, the long-term effects of food AIT are still underestimated. In this regard, eosinophilic gastrointestinal disorders (EGIDs), mainly eosinophilic esophagitis, have been reported as putative complications of OIT for food allergy and sublingual immunotherapy (SLIT) for allergic asthma and rhinitis. Fortunately, these complications are usually reversible and the patient recovers after AIT discontinuation. This review summarizes current knowledge on the possible causative link between eosinophilic gastrointestinal disorders and AIT, highlighting recent evidence and controversies.

Dietary Management of Eosinophilic Esophagitis: Tailoring the Approach

Eosinophilic esophagitis (EoE) is a unique form of non-immunoglobulin E-mediated food allergy, restricted to the esophagus, characterized by esophageal eosinophil-predominant inflammation and dysfunction. The diagnosis requires an esophago-gastroduodenoscopy with esophageal biopsies demonstrating active eosinophilic inflammation with 15 or more eosinophils/high-power field, following the exclusion of alternative causes of eosinophilia. Food allergens trigger the disease, withdairy/milk, wheat/gluten, egg, soy/legumes, and seafood the most common. Therapeutic strategies comprise dietary restrictions, proton pump inhibitors, topical corticosteroids, biologic agents, and esophageal dilation when strictures are present. However, avoidance of trigger foods remains the only option targeting the cause, and not the effect, of the disease. Because EoE relapses when treatment is withdrawn, dietary therapy offers a long-term, drug-free alternative to patients who wish to remain off drugs and still be in remission. There are currently multiple dietary management strategies to choose from, each having its specific efficacy, advantages, and disadvantages that both clinicians and patients should acknowledge. In addition, dietary regimens should be tailored around each individual patient to increase the chance of tolerability and long-term adherence. In general, liquid elemental diets devoid of antigens and elimination diets restricting causative foods are valuable options. Designing diets on the basis of food allergy skin tests results is not reliable and should be avoided. This review summarizes the most recent knowledge regarding the clinical use of dietary measures in EoE. We discussed endpoints, rationale, advantages and disadvantages, and tailoring of diets, as well as currently available dietary regimens for EoE.

Needs Assessment for Eosinophilic Esophagitis Education in School Nurses

Over the past 2 decades, eosinophilic esophagitis (EoE) has become increasingly recognized as a common cause of gastrointestinal morbidity in children. A mainstay of treatment is food avoidance, which must be implemented in both the home and school settings for school-aged children. The aim of this study is to assess school nurses' familiarity with EoE with regard to food avoidance and treatment in the school setting. We conducted a 19-question online survey of 60 school nurses (elementary through high school) recruited from Dauphin, Lebanon, and Lancaster Counties in Pennsylvania. Results indicated that 62% of respondents were familiar with EoE. However, only 22% felt comfortable distinguishing between symptoms of EoE and food-dependent anaphylaxis. Almost all respondents (97%) were interested in learning more about EoE. We report significantly increased familiarity with food-dependent anaphylaxis in comparison with EoE among school nurses. There is an interest and need for increasing education on EoE.

Relationship Between Housing Components and Development of Eosinophilic Esophagitis

BACKGROUND

While the environment contributes to EoE pathogenesis, few environmental risk factors for EoE have been identified.

AIM

To determine whether housing components such as exterior materials, heating systems, and house age are associated with EoE.

METHODS

This case-control study used the UNC EoE clinicopathologic database to identify newly diagnosed EoE patients. Controls were patients without EoE who underwent endoscopy during the study time frame. Housing data were collected from publicly available online sources, and cases and controls were compared. The primary analysis was restricted to those living at their provided address at the time of diagnostic endoscopy. Multivariable logistical regression estimated associations after adjusting for potential confounders.

RESULTS

Of 451 EoE cases and 2421 controls identified, the primary analysis included 158 cases and 769 controls. Compared to controls, EoE cases were more likely to have a house with a brick exterior (35% vs 26%; p = 0.04), gas heating (14% vs 8%; p = 0.06), or forced air (57% vs 45%; p = 0.009). In adjusted analysis, brick exterior was positively associated with EoE diagnosis [aOR 1.83 (95% CI 1.11-3.02)]. The average duration a patient lived in their house before EoE diagnosis was 7.2 ± 5.9 years, while symptom duration prior to diagnosis was 6.8 ± 8.4 years.

CONCLUSION

EoE patients were more likely to have houses with a brick exterior, forced air, or gas heating, and brick exteriors were independently associated with EoE. Since symptoms generally started after moving into a house, housing-related environmental exposures may contribute to EoE disease development.

Eosinophils in Eosinophilic Esophagitis: The Road to Fibrostenosis is Paved With Good Intentions

Eosinophilic esophagitis (EoE) is an antigen-driven disease associated with epithelial barrier dysfunction and chronic type 2 inflammation. Eosinophils are the defining feature of EoE histopathology but relatively little is known about their role in disease onset and progression. Classically defined as destructive, end-stage effector cells, eosinophils (a resident leukocyte in most of the GI tract) are increasingly understood to play roles in local immunity, tissue homeostasis, remodeling, and repair. Indeed, asymptomatic esophageal eosinophilia is observed in IgE-mediated food allergy. Interestingly, EoE is a potential complication of oral immunotherapy (OIT) for food allergy. However, we recently found that patients with peanut allergy may have asymptomatic esophageal eosinophilia at baseline and that peanut OIT induces transient esophageal eosinophilia in most subjects. This is seemingly at odds with multiple studies which have shown that EoE disease severity correlates with tissue eosinophilia. Herein, we review the potential role of eosinophils in EoE at different stages of disease pathogenesis. Based on current literature we suggest the following: (1) eosinophils are recruited to the esophagus as a homeostatic response to epithelial barrier disruption; (2) eosinophils mediate barrier-protective activities including local antibody production, mucus production and epithelial turnover; and (3) when type 2 inflammation persists, eosinophils promote fibrosis.

Eosinophilic esophagitis during sublingual and oral allergen immunotherapy

PURPOSE OF REVIEW

The aim of this review is to discuss the current evidence regarding the development of eosinophilic esophagitis (EoE) in individuals undergoing oral and sublingual immunotherapy (SLIT) for both food and environmental allergens. Cumulative incidence of EoE in patients on allergen immunotherapy for peanut, milk, and egg is estimated.

RECENT FINDINGS

De novo development of EoE in patients undergoing oral and SLIT has been demonstrated on the scale of case reports and prospective randomized trials. However, few individuals with EoE-like symptoms during immunotherapy undergo endoscopy, and the long-term outcomes of immunotherapy-associated EoE are unknown.

SUMMARY

Evidence exists to suggest that allergen immunotherapy could place individuals at risk for the development of EoE, the true incidence of which may vary depending on antigen exposure and methods used to define the condition.

Resolving Clinical Phenotypes into Endotypes in Allergy: Molecular and Omics Approaches

Allergic diseases are highly complex with respect to pathogenesis, inflammation, and response to treatment. Current efforts for allergic disease diagnosis have focused on clinical evidence as a binary outcome. Although outcome status based on clinical phenotypes (observable characteristics) is convenient and inexpensive to measure in large studies, it does not adequately provide insight into the complex molecular determinants of allergic disease. Individuals with similar clinical diagnoses do not necessarily have similar disease etiologies, natural histories, or responses to treatment. This heterogeneity contributes to the ineffective response to treatment leading to an annual estimated cost of $350 billion in the USA alone. There has been a recent focus to deconvolute the clinical heterogeneity of allergic diseases into specific endotypes using molecular and omics approaches. Endotypes are a means to classify patients based on the underlying pathophysiological mechanisms involving distinct functions or treatment response. The advent of high-throughput molecular omics, immunophenotyping, and bioinformatics methods including machine learning algorithms is facilitating the development of endotype-based diagnosis. As we move to the next decade, we should truly start treating clinical endotypes not clinical phenotype. This review highlights current efforts taking place to improve allergic disease endotyping via molecular omics profiling, immunophenotyping, and machine learning approaches in the context of precision diagnostics in allergic diseases. Graphical Abstract.

Disodium cromoglycate treatment reduces TH2 immune response and immunohistopathological features in a murine model of Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is an emergent chronic disease of the esophagus. The immunopathological process in EoE is characterized by Th2 immune response and prominent eosinophilic influx, in response to common food allergens. The classical treatment consists of allergen elimination diet and systemic/topical corticosteroid therapy. Nevertheless, patients do not always comply to treatment, and the prolonged corticosteroid therapy can cause side effects, therefore, there is an immediate need for new therapeutic approach for EoE. Disodium cromoglicate (DSCG) is a substance broadly used in allergic asthma treatment, and a well-known mast cell activation stabilizer. However, its effect in EoE have not been evaluated yet. This study aimed to assess the effects of DSCG treatment in an EoE experimental model. Male Balb/C mice were subcutaneously sensitized for five days with OVA, and subsequently orally OVA-challenged, DSCG administration was performed between the OVA-challenges. DSCG treatment not only reduced eosinophilic and mast cell influx, as well as reduced fibrosis. In addition, tslp, GATA_3, IL-5, FoxP₃ and IL-10 mRNA expression were reduced in esophageal mucosa, associated with lower Th2 (CD3⁺CD4⁺GATA3⁺IL4⁺) and B cells (CD19⁺CD40⁺) number in peripheral lymphoid organs. In conclusion, the data demonstrate DSCG treatment was effective in reducing mast cell activation and Th2 immune response, important immunopathological EoE features. Therefore, the use of DSCG as an EoE treatment can be considered a promising therapeutic approach to treat this disease.

Monitoring Eosinophilic Esophagitis Disease Activity With Blood Eosinophil Progenitor Levels

OBJECTIVES

A minimally invasive biomarker to monitor disease activity is one of the greatest unmet clinical needs of the pediatric eosinophilic esophagitis (EoE) population. We aimed to determine whether circulating eosinophil progenitors (EoPs) could be used as a biomarker to identify pediatric patients with active EoE.

METHODS

In a prospective observational study, peripheral blood samples, symptom history, and laboratory data were collected from pediatric patients undergoing endoscopy for evaluation of EoE on dietary therapy at Cincinnati Children's Hospital. Peripheral blood EoP level was determined by flow cytometry.

RESULTS

Thirty-four children with active (n = 16) and inactive (n = 18) EoE were included in the analysis. EoP levels in the peripheral blood were 3-fold higher in patients with active EoE than inactive EoE (P < 0.0025). Blood absolute eosinophil count did not distinguish between active and inactive EoE (P = 0.16). A cut-off EoP level ≥17 accurately detected active disease in 79% of patients with 94.4% specificity and 62.5% sensitivity (area under the curve 0.81; P < 0.0024). Antihistamine use lowered the threshold EoP level to detect active EoE.

CONCLUSIONS

This study suggests that blood EoP levels may be used as a biomarker to detect active EoE disease in patients undergoing food trials and potentially reduce the need for repeated endoscopies. Larger prospective studies are needed to investigate the effects of antihistamines and swallowed steroids on EoP mobilization into the peripheral blood and longitudinal studies to assess the performance of the assay in individual patients over time.

Strategy for Food Reintroduction Following Empiric Elimination and Elemental Dietary Therapy in the Treatment of Eosinophilic Gastrointestinal Disorders

PURPOSE OF REVIEW

This review presents the available data regarding efficacy of nutritional therapy, highlighting clinical decision points and a strategy for reintroduction of foods following an elemental diet for treatment of eosinophilic gastrointestinal disorders.

RECENT FINDINGS

Elemental and empiric elimination diets are highly effective treatments for eosinophilic gastrointestinal diseases. Standardization in the reintroduction phase, after utilizing the diet for disease remission, is lacking. Clinicians are confronted with multiple challenges regarding the best practice for food reintroduction and identification of potential dietary triggers including order of foods being challenged and duration between endoscopic procedures. Individualization is required for preference and adherence to optimize quality of life and treatment success for this burdensome and life altering immune driven gastrointestinal disorder. Age specific concerns for children, teenagers, and adults should be assessed using a patient centric approach.

Recent advances in potential targets for eosinophilic esophagitis treatments

Introduction: Diagnostic and therapeutic strategies in eosinophilic esophagitis (EoE) are constantly evolving. Recently, the improved understanding of EoE pathogenesis has led to identification of a variety of other potential targets that have never been considered before.Areas covered: In September 2019, we performed structured literature searches in Medline and PubMed, Cochrane meta-analyses, and abstracts of international congresses to review new potential therapeutic approaches for EoE.Expert opinion: The advent of omics disciplines has been helping in finding new molecular targets in EoE pathogenesis and may provide future guidance for deep phenotyping of the disease and therefore facilitate the possibility of personalized medicine. Interestingly, these new treatments should be focused on the restoration of epithelial barrier dysfunction, downregulation of specific molecular pathways of eosinophilic inflammation, and finally, prevention of esophageal remodeling. In this review, we highlight the most recent insights in EoE pathogenesis, which open new pathways for developing new therapeutic targets for clinical practice.

Early Life Risk Factors in Pediatric EoE: Could We Prevent This Modern Disease?

Eosinophilic esophagitis (EoE) is a chronic antigen-mediated inflammatory disease that affects the esophagus. In the last 20 years, a large number of epidemiological studies showed a significant increase in the incidence and prevalence of EoE, especially in developed countries. This phenomenon might correlate to the overall increase in pediatric allergic diseases or might be a result of improved medical awareness and knowledge through modern diagnostic instruments. Since 1993, when EoE was first recognized as a distinct clinical entity, several signs of progress in the pathophysiology of EoE were achieved. However, a few studies reported data on early risk factors for pediatric EoE and how these factors may interfere with genes. Currently, the most defined risk factors for EoE are male sex, Caucasian race, and atopic comorbidities. Other putative risk factors may include alterations in epithelial barrier function and fibrous remodeling, esophageal dysbiosis, variation in the nature and timing of oral antigen exposure, and early prescription of proton pump inhibitors and antibiotics. Notably, the timing and nature of food antigen exposure may be fundamental in inducing or reversing immune tolerance, but no studies are reported. This review summarized the current evidence on the risk factors that might contribute to the increasing development of EoE, focusing on the possible preventive role of early interventions.

Diagnosis and treatment of eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is an eosinophil-rich, TH2 antigen-mediated disease of increasing pediatric and adult worldwide prevalence. Diagnosis requires greater than or equal to 15 eosinophils per high-power field on light microscopy. Symptoms reflect esophageal dysfunction, and typical endoscopic features include linear furrows, white plaques, and concentric rings. Progressive disease leads to pathologic tissue remodeling, with ensuing esophageal rigidity and loss of luminal diameter caused by strictures. Therapies include proton pump inhibitors, elimination diets, and topical corticosteroids. Effective treatment can reverse tissue fibrosis in some patients, as well as decrease the rate of food impactions. Esophageal dilation might be required to increase luminal patency. The chronic nature of EoE necessitates long-term therapy to avoid disease recurrence and complications. This review serves the function of providing the current state-of-the-art diagnostic criteria and disease management for adult and pediatric EoE.

Phenotypes and endotypes in eosinophilic esophagitis

OBJECTIVE

To improve understanding of the heterogeneous presentation of eosinophilic esophagitis (EoE), and its different potential phenotypes and endotypes.

DATA SOURCES

We reviewed studies addressing EoE genetics, risks, natural history, treatment, phenotype, or endotype to assess data relating to differences in the presentation of EoE in children and adults. This review was restricted to articles in the English language.

STUDY SELECTIONS

Data source abstracts, pertinent articles, and book chapters meeting the objectives were critically reviewed.

RESULTS

Data to support differing phenotypes and endotypes in EoE are emerging, but findings are based on multiple studies and therefore sometimes incomparable. Like other atopic disorders EoE is a complex disease with diverse clinical presentations (phenotypes) based on response to therapy, natural history, and association with atopic comorbidities. Different pathogenetic mechanisms (endotypes) may drive the multiple phenotypes. T Helper type 2 inflammation, epithelial barrier defects, enhanced fibrosis, and association with rare monogenetic diseases are the most described endotypes in EoE.

CONCLUSION

Eosinophilic esophagitis is an atopic disorder that is increasing in prevalence and can be difficult to treat. Better understanding of phenotypes and endotypes in EoE may enable future care to be individualized more effectively, resulting in shorter time to remission and fewer endoscopies.

Allergies and Eosinophilic Esophagitis-Current Updates for the Pediatric Gastroenterologist

PURPOSE OF REVIEW

The purpose of this article is to review recent developments demonstrating the role of allergies, the utility of allergy testing, and the role of the allergist in eosinophilic esophagitis (EoE) management.

RECENT FINDINGS

The majority of patients with EoE have concurrent atopic disorders including food anaphylaxis, asthma, allergic rhinitis, and eczema. An atopic population likely is at greater risk for EoE. Delayed type hypersensitivity to food antigens is the most common pathogenic mechanism. Aeroallergens and pollen-food cross-reactivity also can trigger EoE. Th2 cell-mediated adaptive and innate immunity in response to epithelial damage occurs via IL-13- and IL-4-producing T cells and innate lymphoid cells. While IgE testing for foods is insufficient to build an elimination diet, IgE-mediated allergy may play a role in EoE severity and clinical course. There is strong evidence that Th2 immunity drives EoE. Optimal EoE management should include elucidating and managing EoE triggers and concurrent atopic diatheses.

Eosinophilic Esophagitis

Eosinophilic esophagitis is a recently defined condition that has dramatically increased in prevalence in the last several decades. It may occur at any age, but the clinical presentation in young children is often more vague than the classic solid food dysphagia and food impacting that are the major presenting symptoms of eosinophilic esophagitis in adults and adolescents. Successful therapies exist, including medications and dietary modifications, but disease typically recurs when the intervention is discontinued.

Evaluation of long-term course in children with eosinophilic esophagitis reveals distinct histologic patterns and clinical characteristics

BACKGROUND

Eosinophilic esophagitis (EoE) is a chronic and increasingly prevalent antigen-driven disease. There is a paucity of information on long-term course in children.

OBJECTIVE

We sought to understand the longitudinal trajectory of pediatric EoE during routine clinical care.

METHODS

We prospectively enrolled children into an EoE database and reviewed their medical and pathologic records over 13 years.

RESULTS

From 2011 to 2015, 146 children with EoE seen for their first visit at our center had 2 or more years of follow-up and 3 or more endoscopies over an average follow-up period of 5.13 years (range, 2-13 years). Longitudinal eosinophilic inflammation during treatment demonstrated 3 patterns over time. Children with less than 15 eosinophils/high-power field (hpf) for greater than 75% of their follow-up period were termed continuous responders (CRs). Children with waxing and waning inflammation of less than 15 eosinophils/hpf for less than 75% but 25% or more of the follow-up period were termed intermittent responders (IRs). Nonresponders (NRs) were defined as having less than 15 eosinophils/hpf for less than 25% of their follow-up. Fifty-nine (40%) of 146 patients were CRs, 65 (45%) of 146 were IRs, and 22 (15%) of 146 were NRs. CRs differed from IRs and NRs on the parameter of male/female ratio (1:1 in CRs, 4:1 in IRs, and 6:1 in NRs; P < .001) and in their initial response to any therapy, including proton pump inhibitors (P < .001). Endoscopic severity correlated with esophageal eosinophilia (r = 0.73, P < .001). On multivariate analysis, female sex and initial therapeutic response to medications or elimination diet were associated with long-term control of esophageal eosinophilia.

CONCLUSIONS

Long-term pediatric EoE followed 3 different longitudinal trajectories of inflammation. The long-term histologic groups differed significantly in biological sex and initial therapeutic response.

Eosinophilic esophagitis: early diagnosis is the key

Eosinophilic esophagitis (EoE) is a disorder which affects all ages, from infancy through adulthood. It typically affects atopic individuals (Table 1) and is a chronic allergic disorder, with foods ubiquitous in the diet being the most described trigger of this isolated eosinophilic inflammation of the esophagus in both adults and children. This inflammatory process leads to esophageal symptoms such as dysphagia and feeding intolerance. In this review, we provide a brief overview of the current state of EoE therapy and symptomatology and then try to make the case for early diagnosis and treatment to prevent some of the long-term consequences of esophageal inflammation.

Allergic Comorbidity in Eosinophilic Esophagitis: Mechanistic Relevance and Clinical Implications

Allergic eosinophilic esophagitis (EoE) is a chronic, allergen-mediated inflammatory disease of the esophagus, and the most common cause of prolonged dysphagia in children and young adults in the developed world. While initially undistinguished from gastroesophageal reflux disease-associated esophageal eosinophilia, EoE is now recognized as a clinically distinct entity that shares fundamental inflammatory features of other allergic conditions and is similarly increasing in incidence and prevalence. The clinical and epidemiologic associations between EoE and other allergic manifestations are well established. In addition to exaggerated rates of atopic dermatitis, IgE-mediated food allergy, asthma, and allergic rhinitis in EoE patients, each of these allergic manifestations imparts individual and cumulative risk for subsequent EoE diagnosis. As such, EoE may be a member of the "allergic march"-the natural history of allergic manifestations during childhood. Several determinants likely contribute to the relationship between these conditions, including shared genetic, environmental, and immunologic factors. Herein, we present a comprehensive review of allergic comorbidity in EoE. We discuss areas of the genome associated with both EoE and other allergic diseases, including the well-studied variants encoding thymic stromal lymphopoietin and calpain 14, among other "atopic" regions. We summarize ways that environmental factors (such as microbiome-altering pressures and aeroallergen exposure) may predispose to multiple allergic conditions including EoE. Finally, we touch on some fundamental features of type 2 inflammation, and the resulting implications for the development of multiple allergic manifestations. We conclude with an analysis of the "type 2" biologics, and how mechanistic similarities between EoE and the other allergic manifestations have important implications for screening and treatment of the allergic patient.

Correction to: Eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is an atopic condition of the esophagus that has become increasingly recognized over the last 15 years. Diagnosis of the disorder is dependent on the patient’s clinical manifestations, and must be confirmed by histologic findings on esophageal mucosal biopsies. Patients with EoE should be referred to an allergist for optimal management, which may include dietary modifications and pharmacologic agents such as proton pump inhibitors (PPI) and corticosteroids, and for the diagnosis and management of comorbid atopic conditions. Mechanical dilation of the esophagus may also be necessary. The epidemiology, pathophysiology, diagnosis, treatment, and prognosis of EoE are discussed in this review.

Efficacy and Safety of Budesonide in the Treatment of Eosinophilic Esophagitis: Updated Systematic Review and Meta-Analysis of Randomized and Non-Randomized Studies

Background and Objective

Eosinophilic esophagitis (EE) is an immune/antigen-driven inflammation that causes esophageal dysfunction. Budesonide has shown promising effect in the management of EE in multiple studies, and we therefore conducted this systematic review/meta-analysis to assess budesonide efficacy and safety in order to provide more updated and robust evidence.

Methods

In April 2018, we conducted a systematic electronic search through four databases: PubMed, Scopus, Web of Science (ISI), and Cochrane Central. All original studies reporting the efficacy of budesonide in the treatment of EE were included in our meta-analysis. The Cochrane Collaboration tool was employed to assess the risk of bias among included randomized controlled trials, while the Newcastle–Ottawa Scale was used for non-randomized studies.

Results

A total of 12 studies including 555 participants were included in our review. Budesonide showed marked efficacy at the level of histological response compared to placebo [risk ratio (RR) (95% confidence interval (CI)) 11.93 (4.82–29.50); p > 0.001]. Analysis of randomized and non-randomized studies revealed considerable reduction in eosinophil count, with a mean difference (MD) (95% CI) of − 69.41 (− 105.31 to − 33.51; p < 0.001) and 46.85 (33.93–59.77; p < 0.001), respectively. Similarly, there was a marked improvement in the clinical symptoms via the analysis of randomized and non-randomized studies, with an RR (95% CI) of 1.72 (1.22–2.41; p = 0.002) and MD (95% CI) of 2.45 (0.76–4.15; p = 0.005), respectively.

Conclusion

Budesonide showed significant effect at all treatment endpoints. However, since budesonide carries a risk of candidiasis and our inferences are based only on a small number of included studies, more research is warranted to clarify these results.

Electronic supplementary material

The online version of this article (10.1007/s40268-018-0253-9) contains supplementary material, which is available to authorized users.

Pathophysiology of eosinophilic esophagitis: recent advances and their clinical implications

Introduction: Diagnostic and therapeutic strategies in eosinophilic esophagitis (EoE) are evolving. New knowledge regarding the pathophysiology of EoE has been the foundation for updated diagnostic recommendations and new therapeutic trials. Areas covered: We performed structured literature searches in Medline and PubMed, Cochrane meta-analyses, and abstracts of international congresses to review therapeutic approaches for EoE in July 2018. Additional articles were obtained by perusing the references of articles identified in the original PubMed search. Articles were excluded if they did not focus on the mechanism of disease, diagnosis, or treatment of humans with EoE. Expert commentary: Recent advances in the understanding of mechanisms underlying the pathology of EoE have resulted in significant change in the diagnostic algorithm for EoE, and are identifying promising potential targets for personalized medicine. There is a clinical need for improved targeted therapy for EoE, and better understanding the underlying pathophysiology of EoE will help to determine therapeutic targets. In this review, we highlight key mechanisms in the pathophysiology of EoE and how they are being utilized to change therapy in EoE.