Chapter 26: Eosinophilic esophagitis.

Eosinophilic esophagitis (EoE) is distinguished from gastroesophageal reflux disease (GERD) by persistent esophageal eosinophilia despite medical therapy with proton-pump inhibitors for 4-6 weeks. In children, symptoms vary by age groups such as feeding disorders in 2 year olds; vomiting in 8 year olds; and abdominal pain, dysphagia, and/or food impaction in adolescents. Most adults present with dysphagia, food impaction, heartburn or chest pain. Common endoscopic features in adults with EoE include linear furrows (creases that orient longitudinally), mucosal rings (esophageal "trachealization"), small-caliber esophagus, white plaques or exudates (which are microabscesses of eosinophils), and strictures. Children often present with similar endoscopic features, but one-third of pediatric patients with EoE have normal endoscopy. Histological features of EoE include increased intramucosal eosinophils in the esophagus (≥15 eosinophils/high-power field) without similar findings in the stomach or duodenum. There also may be eosinophilic microabscesses. In addition to evidence of mast cell activation, mucosa from patients with EoE have increased IL-5, supporting eosinophilia, and up-regulation of gene expression of eotaxin-3, a chemokine important in eosinophil migration. The majority of patients have evidence of either aeroallergen and/or food sensitization. An elemental/amino acid-based formula diet has shown to be effective in children but may not be well tolerated by adults because of taste and volume or high expense. Topical corticosteroids improve esophageal eosinophilia and symptoms and have become the "gold standard" of pharmacotherapy.