What is eosinophilic esophagitis?

What is Eosinophilic Esophagitis?

Eosinophilic esophagitis (EoE) is a chronic, immune/antigen-mediated disease of the esophagus characterized by symptoms of esophageal dysfunction (dysphagia, food impaction in adults; feeding problems, vomiting in children) and histologically by eosinophil-predominant inflammation with ≥15 eosinophils per high-power field (or ≥15 eosinophils/0.3 mm²) on esophageal biopsy. 1

Core Disease Characteristics

Pathophysiology:

• EoE represents an aberrant immune response driven by antigens, involving multiple pathogenic pathways including genetic susceptibility (polymorphisms in thymic stromal lymphopoietin protein gene) 1
• The disease causes eosinophilic infiltration throughout all layers of the esophagus, triggering chronic inflammation that leads to esophageal remodeling and fibrosis 2
• This is fundamentally different from gastroesophageal reflux disease and does not lead to Barrett's esophagus or esophageal adenocarcinoma 1

Clinical Presentation:

• Adults: Dysphagia (difficulty swallowing) and food impaction are the hallmark symptoms, often accompanied by heartburn and chest pain 3, 2
• Children: Feeding problems, failure to thrive, abdominal pain, vomiting, and feeding intolerance predominate 1
• The disease affects both pediatric and adult populations with rapidly increasing prevalence (approximately 34.4 per 100,000 in Europe and North America) 3

Diagnostic Criteria

EoE is a clinicopathologic diagnosis requiring BOTH clinical symptoms AND histologic findings: 1

• Histologic threshold: ≥15 eosinophils per high-power field (equivalent to ≥15 eosinophils/0.3 mm² or >60 eosinophils/mm²) on esophageal biopsy specimens 1, 4
• Symptom requirement: Evidence of esophageal dysfunction appropriate to age group 1
• Exclusion criteria: Other causes of esophageal eosinophilia must be ruled out, including proton pump inhibitor (PPI)-responsive esophageal eosinophilia, gastroesophageal reflux disease, achalasia, and other conditions 1, 3

Critical diagnostic pitfall: Esophageal eosinophilia alone is NOT sufficient for diagnosis—clinical correlation is mandatory, as neither histology nor symptoms should be interpreted in isolation 1

Endoscopic Features

Common findings (none pathognomonic but highly suggestive when multiple are present): 1

• Longitudinal furrows (vertical lines in esophageal mucosa)
• White exudates, specks, or nodules representing eosinophilic infiltrates
• Circular rings ("felinization," "trachealization," or concentric rings)
• Crêpe paper mucosa with linear shearing during endoscope passage
• Esophageal strictures (proximal, middle, or distal)
• Narrow-caliber esophagus

Associated Features

Allergic comorbidities:

• Patients demonstrate high rates of concurrent allergic conditions, particularly food sensitization, compared to the general population 1
• Strong association with atopic diseases including asthma, eczema, and hay fever 4

Natural History and Complications

Disease course:

• EoE is a chronic disease requiring long-term follow-up and treatment, with persistent or relapsing symptoms common after treatment discontinuation 1
• The disease does NOT limit life expectancy and does NOT progress to esophageal metaplasia or adenocarcinoma 1

Major complications:

• Esophageal strictures and small-caliber esophagus resulting from chronic inflammation and remodeling 1, 5
• Food impaction requiring emergency intervention 3
• In children: failure to thrive and feeding intolerance 1

Important caveat: Even mild persistent eosinophilia can cause end-organ damage if left untreated, emphasizing the need for ongoing monitoring and treatment 4

Treatment Paradigm

Proven therapeutic options include: 1

• Chronic dietary elimination (highly effective with 97.6% clinicopathologic response in some studies) 1
• Topical corticosteroids (64.9% histologic remission rate versus 13.3% for placebo) 3
• Proton pump inhibitors (41.7% histologic response rate) 3
• Esophageal dilation for symptomatic strictures 1, 5

Treatment response confirmation: Disease remission should be documented with dietary exclusion, topical corticosteroids, or both, as part of the diagnostic algorithm 1