D2.189 - Eosinophilic Esophagitis Induced by Sublingual Immunotherapy (SLIT): A Rare but Emerging Side Effect
Case report
Background
Eosinophilic esophagitis is a chronic, immune-mediated condition where eosinophils build up in the esophagus, leading to symptoms like dysphagia and food impaction. Sublingual immunotherapy (SLIT) is generally considered a safer and more convenient alternative to traditional allergy shots (SCIT). However, there is growing concern that SLIT might trigger EoE in individuals who are genetically predisposed. While SLIT is usually well-tolerated, it's important to recognize that EoE, though rare, is a serious potential complication.
Case Presentation
This case involves a 19-year-old boy with severe allergic rhinitis who began SLIT Oralvac for Dermatophagoides pteronyssinus and Dermatophagoides farinae. Seven months into treatment, he developed progressive dysphagia and pain behind the breastbone. He had no prior history of esophageal symptoms. To determine the cause of his symptoms, an esophagogastroduodenoscopy was performed, revealing mucosal edema, furrowing, and white spots. A biopsy confirmed eosinophilic esophagitis with 29 eosinophils per high-power field. Laboratory tests showed an eosinophil count of 352 cells/µL and total IgE level 334 kU/L. Given these findings, SLIT was discontinued, and the patient was treated with topical corticosteroids and dietary modifications. He responded excellently to this approach, with significant symptom improvement.
Discussion
SLIT is believed to induce EoE due to prolonged allergen exposure on the mucosal surface, triggering a Th2-mediated inflammatory response. Key pro-inflammatory cytokines, such as IL-5 and IL-13, contribute to eosinophil recruitment and esophageal tissue remodeling. Individuals with certain genetic predispositions, including CAPN14 mutations, may be more susceptible to EoE development following SLIT. While SLIT is generally considered safe, physicians should remain vigilant when patients undergoing this therapy begin to exhibit esophageal symptoms.
Conclusion
Eosinophilic esophagitis is a rare but serious complication of SLIT that may not always be immediately suspected. Physicians should be vigilant in evaluating any patient undergoing SLIT who develops dysphagia or other esophageal symptoms. Diagnosis can be confirmed through endoscopic examination and eosinophil counts, guiding appropriate management. Further research is needed to identify the best screening strategies for patients at higher risk, ultimately leading to improved outcomes and more effective treatment approaches.
