Dr Gillian Skardoon ( left ) Gastroenterology consultant , Alfred Health and Monash Health , Melbourne , Victoria .

Associate Professor Hamish Philpott ( centre ) Gastroenterology consultant , Northern Adelaide Local Health Network ; senior clinical lecturer , University of Adelaide , SA .

Associate Professor Rebecca Burgell ( right ) Head of Functional Gut Disorder Clinic at the Alfred Hospital ; head of Functional Gastrointestinal Disorders Service , Monash University , Melbourne , Victoria .

Copyright © 2024 Australian Doctor All rights reserved . No part of this publication may be reproduced , distributed or transmitted in any form or by any means without the prior written permission of the publisher . For permission requests , email : howtotreat @ adg . com . au

This information was correct at the time of publication : 14 June 2024

BACKGROUND

EOSINOPHILIC oesophagitis is a

chronic T-helper 2 cell immune mediated inflammatory disorder of the oesophagus . 1

The presentation of eosinophilic oesophagitis ( EoE ) varies depending on the age of onset , with symptoms of dysphagia , odynophagia , heartburn and food impaction predominating in adults . Children present with abdominal pain and faltering growth , in addition to food bolus impaction . These symptoms may result in significant morbidity and a negative impact on health-related quality of life . 2

The importance of prompt , targeted therapy cannot be underestimated ; this condition has been shown to progress in a proportion of patients from a predominantly inflammatory condition to that of a fibrostenotic process because of tissue remodelling and stricture formation . 3

This How to Treat covers the risk factors for EoE , clinical manifestations , diagnostic criteria and treatment options , including possible future medical therapies . It aims to ensure that GPs are confident in identifying patients who may have EoE

and that they have a comprehensive understanding of the treatment options available for these patients .

EPIDEMIOLOGY

EoE was initially described in the early 1990s . Since then , both the incidence and prevalence of the condition have rapidly increased . It is currently estimated at 5-10 / 100,000 people a year and 0.5-1 case / 1000 people , respectively . 4 , 5

Prevalence data demonstrate 34 cases / 100,000 in children and 42.2 cases / 100,000 in adults . 6 , 7 Incidence trends from the Netherlands demonstrate that EoE has multiplied 316-fold , with a male predominance ( 3:1 ) and age range of 29-49 . 8 Up to 15 % of patients undergoing upper endoscopy for dysphagia are found to have EoE . 9

The cause for this pronounced increase in incidence is unknown and cannot be explained by detection bias alone . It correlates with increases in other diseases , such as atopic conditions and inflammatory bowel disease . 8

PATHOPHYSIOLOGY

THE pathophysiology of EoE is

incompletely understood ; however , it is thought to be a T-helper 2 cell – mediated condition . Interestingly , despite eosinophils being the hallmark diagnostic cell for EoE , numerous immune cell types are likely to be involved . 10 As part of the adaptive immune system , when an antigen-presenting cell activates a naïve helper T-cell in peripheral lymphoid tissue , the T-cell can differentiate into two functionally distinct subclasses : T-helper 1 ( Th1 ) or T-helper 2 ( Th2 ) subclasses , which are distinguished by the cytokines they secrete . 11 Th1 cells secrete interferon-γ , TNF-α / β , macrophages and cytotoxic T-cells , and they may stimulate B-cells to secrete IgG antibodies that activate complement . Th2 cells secrete interleukin ( IL ) -4; IL-5 ; IL-13 ; and chemokines , such as eotaxin ; and they can stimulate B-cells to secrete most classes of antibodies , including immunoglobulin E ( IgE ) and immunoglobulin G ( IgG ) that bind to mast cells , basophils and eosinophils . 11

EoE is thought to be caused by a dysregulated Th2 immune response following exposure to a stimulus ( generally dietary , such as dairy or

gluten , but also aeroallergens ) in a susceptible individual with an underlying epithelial barrier dysfunction . 12 This activates a cascade of inflammatory cytokines — including IL-4 , IL-5 , IL-13 and eotaxin-3 — which induces eosinophilic activation and infiltration ( see figure 1 ). 13 Curiously , IgE does not seem to be involved , and thus traditional allergy tests that measure IgE have no clinical utility .

Numerous factors have been implicated in the rapid rise of this

2 , 14 – 16 condition . ( see box 1 ).

Regarding the genetic predisposition of this condition , nuclear-family heritability is high ( 72 %), with a twin cohort analysis providing further evidence of common environment ( 81 %) compared with additive genetic heritability ( 14.5 %). 16 Genetic variants — such as CAPN14 , TSLP , TSLPR , CCL26 and FLG —

16 , 17 have been associated with EoE . However , the risk of EoE is low — approximately 1.8-2.4 % — for relatives of those who are diagnosed with the condition . 16 The role of epigenetics in this condition must be considered given the complex interactions between environmental