What are the causes of eosinophilic esophagitis and how is it treated?

Eosinophilic Esophagitis: Causes and Treatment

Causes

Eosinophilic esophagitis is a chronic, Th2-mediated immune disease triggered by food or environmental antigens that drives eosinophilic infiltration into all layers of the esophagus. 1, 2

• The disease operates through a local IgG4 mechanism rather than systemic IgE-mediated allergy, distinguishing it from classic food allergies. 3
• Genetic susceptibility combined with environmental factors—particularly early-life antibiotic exposure—increases risk. 2
• Food antigens are the primary triggers, with cow's milk (42% of cases), eggs (21.5%), and wheat (10.9%) being the most common culprits. 4
• Aeroallergens may play a role, though their contribution is still under investigation. 5
• The chronic inflammatory process causes esophageal remodeling and fibrosis, leading to strictures if untreated. 1, 6

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Treatment Approach

First-Line Therapy: Proton Pump Inhibitors

Start with a proton pump inhibitor (omeprazole 20 mg twice daily) for 8–12 weeks as first-line treatment due to its safety, low cost, and substantial efficacy. 7, 4

• PPIs achieve histologic remission (< 15 eosinophils per high-power field) in 30–50% of patients, compared to 13.3% with placebo. 2, 6
• PPI-responsive EoE is clinically, endoscopically, histologically, and molecularly identical to non-PPI-responsive EoE—this is true eosinophilic esophagitis, not just GERD. 5, 4
• The PPI trial is a therapeutic intervention, not a diagnostic test to "rule out" EoE. 4

Second-Line Therapy: Topical Corticosteroids

If PPIs fail, switch to swallowed topical corticosteroids (fluticasone or budesonide), which achieve histologic remission in 60–87% of patients. 7, 4, 6

• The American Gastroenterological Association issues a strong recommendation for topical corticosteroids based on high-quality evidence. 4
• Topical steroids are significantly more effective than placebo (64.9% vs. 13.3% remission). 2

Mandatory Endoscopic Monitoring

Perform repeat endoscopy with biopsies from at least six different esophageal sites after 8–12 weeks of any therapy while the patient remains on treatment. 5, 7, 4

• Symptom improvement does not reliably predict histologic healing—approximately 41% of patients report symptomatic improvement without true histologic remission. 4
• Histologic remission is defined as < 15 eosinophils per 0.3 mm² (high-power field). 5
• Failure to confirm mucosal healing allows persistent inflammation and progressive fibrosis despite apparent clinical benefit. 4

Maintenance Therapy

Continue the effective PPI or topical corticosteroid indefinitely after achieving histologic remission, as relapse rates are extremely high after drug withdrawal. 5, 7, 4

• Maintenance therapy prevents recurrent dysphagia, food impaction, and esophageal stricture formation. 5, 4
• Limited data suggest PPIs may maintain sustained histologic response better than low-dose topical steroids. 5, 4
• Patients who prioritize avoiding long-term steroid exposure may reasonably choose cessation after remission, provided close clinical follow-up is maintained. 5

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Dietary Management

Elimination Diet Strategy

Elimination diets are effective but require supervision by an experienced dietitian throughout both elimination and reintroduction phases. 5, 4

• Six-food elimination diet (SFED): Removes milk, wheat, egg, soy, peanuts/tree nuts, fish/shellfish—achieves 72–79% histologic remission but has lower patient acceptance (39% decline due to burden). 5, 4, 6
• Four-food elimination diet (FFED): Removes milk, wheat, egg, soy—achieves 60% remission with 28% declining to escalate. 4
• Two-food elimination diet (TFED): Removes milk and wheat—achieves 43% remission with best adherence. 4, 6
• Elemental (amino acid) diet: Achieves > 90% remission but is reserved for refractory cases due to poor palatability, high cost, and frequent need for feeding tubes. 4, 6

Critical Dietary Considerations

• Allergy testing (skin prick, serum IgE, patch testing) has limited predictive value (~45% efficacy) and should not guide food elimination strategies. 5, 4
• Foods proven to trigger disease must remain excluded indefinitely; spontaneous tolerance is not expected. 4
• Systematic reintroduction requires repeat endoscopy and biopsy every 8–12 weeks to identify specific triggers. 4
• Dietitian involvement is mandatory to prevent nutritional deficiencies, ensure adequate micronutrient intake (calcium, vitamin D), and monitor growth in children. 5, 4
• Screen for celiac disease before removing wheat/gluten. 4

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Management of Fibrostenotic Disease

Perform conservative endoscopic dilation (balloon or bougie) for patients with dysphagia from EoE-related strictures, as it improves dysphagia in ~87% of cases. 7, 4

• Dilation does not treat underlying inflammation and must be combined with anti-inflammatory therapy (PPI or topical steroid) for optimal outcomes. 7, 4
• Perforation occurs in ~0.4% of procedures and hospitalization in ~1.2%; most perforations were linked to more aggressive techniques used before 2009. 4
• Dilation is safe and effective but should be performed conservatively to minimize complications. 4, 3

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Common Pitfalls and Caveats

• Never equate symptom resolution with histologic healing—endoscopic assessment is mandatory because symptoms do not correlate with mucosal eosinophilia. 5, 7, 4
• Do not discontinue maintenance therapy after achieving remission unless the patient explicitly prioritizes avoiding long-term medication and commits to close follow-up. 5, 7
• Do not use allergy testing to guide dietary elimination—EoE is principally a non-IgE-mediated disorder. 5, 4
• Do not overlook coexisting GERD and EoE—the two conditions are not mutually exclusive and can coexist in the same patient, requiring treatment for both. 5, 4
• Do not perform dilation without concurrent anti-inflammatory therapy—dilation alone does not address the underlying inflammatory process. 7, 4
• Do not use polymeric or semi-elemental formulas for refractory cases—only amino acid-based elemental formulas are effective. 4

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Treatment Algorithm Summary

1. Initial therapy: Omeprazole 20 mg twice daily for 8–12 weeks. 7, 4
2. Endoscopic assessment: Repeat endoscopy with ≥ 6 biopsies from different sites while on treatment. 5, 7, 4
3. If remission achieved: Continue maintenance therapy indefinitely. 5, 7, 4
4. If PPI fails: Switch to swallowed topical corticosteroids (fluticasone or budesonide). 7, 4
5. If pharmacotherapy fails or patient prefers: Initiate supervised elimination diet (start with TFED, escalate to FFED or SFED if needed). 5, 4
6. If strictures present: Perform conservative endoscopic dilation combined with anti-inflammatory therapy. 7, 4
7. Ongoing monitoring: Repeat endoscopy with biopsies at appropriate intervals to confirm sustained remission. 5, 7, 4