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|Classification and external resources|
|Classification and external resources|
Eosinophilic esophagitis (eosinophilic oesophagitis), also known as allergic oesophagitis, is an allergic inflammatory condition of the esophagus that involves eosinophils, a type of white blood cell. Symptoms are swallowing difficulty, food impaction, and heartburn.
EoE is associated with oesophageal strictures, and often presents with food impaction, dysphagia, and heartburn. In addition, young children with eosinophilic esophagitis may present with feeding difficulties. It is more common in males, and affects both adults and children.
EoE is characterised by a dense eosinophilic infiltrate into the squamous epithelium of the oesophagus. This is thought to be probably an allergic reaction against ingested food, based on the important role eosinophils play in allergic reactions. Eosinophils are inflammatory cells that release a variety of cytokines which inflame the surrounding oesophageal tissue. This results in symptoms of pain, visible redness on endoscopy, and a natural history that may include stricturisation.
A characteristic set of genes termed the "EE transcriptome" described by Professor Marc Rothenberg MD, PhD, is expressed and distinguishes patients with EoE from unaffected individuals or from patients with other forms of esophagitis.
The EE transcriptome has now been developed into a 94 gene panel, called the EE Diagnostic Panel (EDP) which provides a rapid and accurate means to diagnose EoE and monitor disease activity.
The diagnosis of EoE is typically made clinicopathologically.
Clinical Findings. Clinically, EoE can only be diagnosed if gastroesophageal reflux is not responsive to a 6 week trial of twice-a-day high-dose proton-pump inhibitors (PPIs) or if a negative ambulatory pH study rules out gastroesophageal reflux disease (GERD).
Histology. On esophagogastroduodenoscopic biopsy, numerous eosinophils can be seen in the superficial epithelium. A minimum of 15 eosinophils per high-power field are required to make the diagnosis. Eosinophilic inflammation is limited to the oesophagus alone, and does not extend into the stomach or duodenum. Profoundly degranulated eosinophils may also be present, as may microabcesses and an expansion of the basal layer.
Endoscopy. Endoscopically, ridges, furrows, or rings may be seen in the oesophageal wall. Sometimes, multiple rings may occur in the esophagus, leading to the term "corrugated esophagus" or "feline esophagus" due to similarity of the rings to the cat esophagus. Presence of white exudates in esophagus is also suggestive of the diagnosis.
Radiology. Radiologically, the term "ringed esophagus" has been used for the appearance of eosinophilic esophagitis on barium esophagrams to contrast with the appearance of transient transverse folds sometimes seen with esophageal reflux (termed "feline esophagus").
Treatment strategies include dietary modification to exclude food allergens, medical therapy, and mechanical dilatation of the esophagus.
The initial approach to the disorder is often allergy evaluation in an attempt to identify the allergens in the diet or environment that may be triggering the condition. If the offending agent is found, the diet is modified so that these allergens are eliminated. There are cases, especially in children, where there are multiple food allergies involved. Some patients require an elemental diet through the use of a specialty formula. Sticking to this diet and drinking the required amount of formula can be difficult. The use of feeding tubes in these situations is often required.
First-line therapy is with swallowed liquid corticosteroids and other anti-inflammatories, including fluticasone, a topical viscous budesonide oral suspension. . Patients with severe symptoms despite these interventions may require oral corticosteroids such as methylprednisolone. Other anti-inflammatory agents have also been trialled, including leukotriene antagonists such as montelukast, anti-interleukins such as the anti-IL-5 monoclonal antibody mepolizumab, and antihistamines such as loratadine. Unfortunately, these have shown little clinical benefit.
Mechanical dilatation may be considered in severe cases of EoE that have progressed to esophageal stricture or severe stenosis. Dilatation is accomplished by passing dilators through the mouth and down the esophagus to gently expand its diameter. As the esophagus of patients with EoE is rather thin and delicate, care is taken not to perforate the esophagus by overzealous dilatation.
PPI use. Despite EoE being historically thought of as refractory to PPI treatment, there is some recent evidence to suggest a significant proportion of patients suffering from EoE achieving remission following PPI therapy.