Will eosinophilic esophagitis show on an Esophagogastroduodenoscopy (EGD)?

Diagnosis of Eosinophilic Esophagitis on EGD

Eosinophilic esophagitis (EoE) can be diagnosed on esophagogastroduodenoscopy (EGD), but requires esophageal biopsies for definitive diagnosis, as endoscopic visual findings alone are insufficient for diagnosis.

Endoscopic Findings in EoE

• EGD may reveal characteristic endoscopic features of EoE including esophageal rings, longitudinal furrows, whitish exudates, edema, diffuse esophageal narrowing, narrow-caliber esophagus, and esophageal lacerations (crepe paper appearance) 1
• However, these endoscopic features are not pathognomonic for EoE as they can be seen in other esophageal disorders 1
• Endoscopic findings alone have limited diagnostic utility - in one study, only 38% of patients with endoscopic features suggestive of EoE were confirmed to have the condition on biopsy 1
• Importantly, 9.8% of patients with normal-appearing esophagus on endoscopy had histologic evidence of EoE 1

Biopsy Requirements for Diagnosis

• Endoscopy with esophageal biopsy remains the only reliable diagnostic test for EoE 1
• Multiple biopsies from at least two esophageal levels (proximal and distal) are recommended to increase diagnostic yield 1
• Targeting areas with visible inflammation when present increases diagnostic yield 1
• The optimal number of biopsies is 2-6 specimens:
  • 2 biopsies: 84% sensitivity
  • 3 biopsies: 97% sensitivity
  • 6 biopsies: 100% sensitivity 1
• Biopsies should be obtained even when the esophageal mucosa appears normal 1

Diagnostic Criteria for EoE

• Diagnosis requires:
  1. Symptoms of esophageal dysfunction
  2. ≥15 eosinophils per high-power field (or ~60 eos/mm²) on esophageal biopsy
  3. Exclusion of other causes of esophageal eosinophilia 1
• Isolated esophageal eosinophilia without corroborating symptoms and exclusion of other causes is insufficient for diagnosis 1

Biopsy Site Considerations

• Biopsies from the lower esophagus have been shown to have significantly higher yield for detecting EoE compared to the middle esophagus 2
• Areas with exudates and furrows demonstrate higher eosinophil counts and are preferred biopsy sites 2, 3
• In patients with normal-appearing esophagus or subtle findings, more biopsies may be needed to identify diagnostic eosinophil counts 3

Pitfalls and Caveats

• Proton pump inhibitor (PPI) therapy may affect biopsy results - patients on PPI therapy who have normal biopsies cannot be definitively ruled out for EoE 1
• PPI-responsive esophageal eosinophilia (PPI-REE) can appear identical to EoE on endoscopy and biopsy, requiring a PPI trial to differentiate 4
• No clinical or endoscopic features can reliably distinguish PPI-REE from EoE before a PPI trial 4
• Gastric and duodenal biopsies should also be obtained in children and when clinically indicated in adults to exclude other causes of esophageal eosinophilia 1

Emerging Technologies

• Reflectance confocal microscopy shows promise as a potential tool for assessing eosinophilic infiltration in the esophagus without requiring traditional biopsies 5
• However, this technology is still investigational and not yet part of standard clinical practice 5

In conclusion, while EGD is essential for diagnosing EoE, the visual endoscopic examination alone is insufficient. Definitive diagnosis requires multiple esophageal biopsies demonstrating ≥15 eosinophils/hpf in the appropriate clinical context, even when the esophagus appears normal endoscopically.