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Eosinophilic esophagitis (EoE) is a chronic allergic disease of the esophagus characterized clinically by symptoms related to esophageal dysfunction and histologically by eosinophil-predominate esophageal inflammation. Aggregation of eosinophils within the esophagus is caused by exposure to food allergens, leading to a cytokine response of T helper type 2 (Th2) cells mediated by interleukin (IL)-4 , IL-5, and IL-13.1 This eosinophilic accumulation results in an inflammatory cascade,  which leads to remodeling of the esophageal mucosa and potential subsequent subepithelial fibrosis. Eosinophilia and fibrosis prevent appropriate esophageal function and cause symptoms associated with esophageal dysmotility.1

Epidemiology

EoE has been described as the most common cause of dysphagia and food impaction in the emergency department setting.2 With a 10-fold increase in patients living with EoE over the past 30 years, the prevalence of EoE is approaching that of Crohn disease and ulcerative colitis,3 which may be due to the rising incidence of allergic diseases in general but also may be influenced by an increased recognition of the disease. Recent studies have suggested a genetic predisposition to EoE. Hoboken et al found a positive family history (ie, first-degree relatives) of EoE in up to 10% of pediatric patients.1 Approximately two-thirds of patients with EoE have a family history of atopy, including seasonal allergies, IgE-mediated food allergies, or asthma.4 EoE has been described in both children and adults, and nearly all studies on EoE have demonstrated a predominance in white men.2

History and Physical Examination

The classic presentation of EoE consists of recurrent attacks of dysphagia and/or food impaction. Dysphagia is 3 times more likely to occur in an adult with EoE than heartburn, dyspepsia, and chest pain combined.2 Symptoms in children vary by age and include poor eating (infants), abdominal pain and vomiting (school-aged children), and reflux symptoms and/or dysphagia in teenagers (Figure 1).1,2

Subtle and subclinical symptoms of dysphagia often can include eating small portions of food slowly and requiring large amounts of liquid to lubricate the esophagus.4 Patients with EoE may avoid ingesting breads and meats and have difficulty swallowing pills. Food impaction in the esophagus should trigger consideration of EoE in the emergency department setting. One clinical series reported that 18 of 54 patients presenting to the emergency department with food impaction would ultimately be diagnosed with EoE.2 

Other atopy-associated diseases linked to EoE include atopic dermatitis (eczema), allergic rhinitis, and allergic and/or nonallergic asthma. When atopy is present, serum immunoglobulin E (IgE) may be elevated as a response to allergic diseases of the skin, lungs, or extraesophageal mucous membranes; however, EoE alone has not been associated with an increase in serum IgE.2,3

The physical examination of a patient with EoE is usually unremarkable, although weight loss from dysphagia and undereating may be present.

Figures 1A, 1B. Comparison of symptoms of eosinophilic esophagitis in children and adults. 1,2 

Diagnostic Methods

Three diagnostic criteria define EoE: the presence of age-specific symptomatology, ≥15 eosinophils per high-power field (hpf) on histologic examination, and the exclusion of alternative etiologies of esophageal eosinophilia such as gastroesophageal reflux disease (GERD).1 Classic endoscopic findings of EoE include edema, strictures, trachealization (circular rings resembling the trachea), white exudates, and linear furrowing (deep creases along the length of the esophagus).2 

Until recently, the diagnostic criteria for EoE included histologic evidence from an esophagogastroduodenoscopy (EGD) only after a failed 2-month trial of high-dose acid suppressive therapy. However, a subset of EoE identified as proton pump inhibitor-responsive EoE (PPI-REE) has been classified. Patients with this diagnosis  respond to PPIs and may not exhibit histologic or endoscopic evidence of the disease if taking a PPI when EGD is performed. With this new information, it is imperative that patients discontinue treatment with PPIs for 3 to 4 weeks before endoscopy to avoid misdiagnosis.5