Eosinophilic esophagitis (EoE) is a chronic immune-mediated disease affecting the esophagus, the tube that carries food from the mouth to the stomach. Its recognition has increased significantly over recent decades. This article explores its prevalence and the factors influencing its diagnosis.
What is Eosinophilic Esophagitis?
Eosinophilic esophagitis is an inflammatory condition of the esophagus characterized by a buildup of eosinophils, a type of white blood cell, in the esophageal lining. This accumulation occurs as an immune response to certain allergens, often food or environmental substances. The inflammation can lead to various symptoms, including difficulty swallowing (dysphagia), food getting stuck in the throat (food impaction), and chest or abdominal pain. In children, symptoms may be less specific, presenting as feeding difficulties, failure to thrive, or vomiting.
Diagnosis of EoE typically involves an upper endoscopy with biopsies of the esophagus. During an endoscopy, a thin, flexible tube with a camera examines the esophageal lining for signs of inflammation like rings, furrows, or white spots. Multiple small tissue samples are then taken from different parts of the esophagus and examined under a microscope to confirm the presence of eosinophils, usually requiring at least 15 eosinophils per high-power field. Other conditions that can cause eosinophil accumulation in the esophagus, such as gastroesophageal reflux disease (GERD), must be ruled out before a definitive EoE diagnosis.
Current Prevalence and Incidence
The perception of EoE has shifted to one more commonly encountered, with a notable increase in reported cases globally. The incidence, representing new cases, and prevalence, indicating existing cases, have shown a significant rise over the past few decades. Globally, the pooled incidence of EoE is estimated to be around 5.31 cases per 100,000 people per year, while the pooled prevalence is approximately 40.04 cases per 100,000 people.
These figures vary by region, with higher rates observed in high-income countries, particularly in North America and Europe, compared to low- or middle-income countries. For instance, in Europe, a systematic review and meta-analysis reported an overall prevalence of 32.7 per 100,000 and an incidence of 4.1 per 100,000. In the United States, estimated prevalence rates have ranged from 25.9 to 142.5 per 100,000 persons.
The increase in diagnosis rates has been steady over time, with prevalence estimates rising significantly. From 1976 to 2001, prevalence was estimated at 8.18 cases per 100,000 inhabitant-years, which surged to 74.42 cases per 100,000 inhabitant-years between 2017 and 2022.
Factors Affecting Diagnosis Rates
The observed increase in EoE diagnoses can be attributed to several contributing factors beyond a true rise in disease occurrence. Heightened awareness among healthcare professionals plays a significant role, as clinicians are now more likely to consider EoE when patients present with esophageal symptoms. This increased recognition leads to more frequent and targeted diagnostic testing.
Improvements in diagnostic methods have also contributed to higher detection rates. The widespread adoption of upper endoscopy with biopsies as the standard diagnostic approach allows for definitive identification of eosinophil infiltration in the esophagus. Updated diagnostic criteria provide clearer guidelines for identifying EoE and distinguishing it from other conditions like proton pump inhibitor-responsive esophageal eosinophilia (PPI-REE).
While environmental and genetic factors may also influence the actual occurrence of EoE, their direct impact on overall prevalence and incidence is still under investigation. The parallel increase in EoE with other allergic conditions, such as asthma and allergies, suggests a potential link to broader environmental changes.
Demographics of EOE
EoE affects various populations, with specific demographic patterns observed in its distribution. It can occur at any age, from infancy to older adulthood, but is frequently diagnosed in children and young adults. The average age of diagnosis in children is around 8.6 years, and some studies indicate a higher prevalence in adults.
There is a clear gender predisposition, with EoE being more common in males than in females. Males account for a significant majority of diagnosed cases, often around 60-75%. Regarding racial or ethnic predispositions, studies in the United States indicate a higher prevalence among Caucasians compared to African-Americans and Asians.
A strong association exists between EoE and other atopic conditions, which are allergic disorders. A substantial proportion of individuals with EoE, approximately 60-80%, also have concomitant allergic conditions such as asthma, eczema (atopic dermatitis), allergic rhinitis (hay fever), and food allergies. The likelihood of having EoE increases with the number of co-occurring atopic conditions.