Allergic esophagitis, also known as eosinophilic esophagitis (EoE), is a chronic inflammatory condition that impacts the esophagus, the muscular tube connecting the mouth to the stomach. It involves an allergic reaction within the esophageal lining. This condition can lead to various issues with swallowing and discomfort.
Understanding Allergic Esophagitis
Allergic esophagitis is an immune system disease where a type of white blood cell, called an eosinophil, builds up in the lining of the esophagus. This accumulation is a reaction to allergens, leading to inflammation and potential injury of the esophageal tissue. The inflammation can cause the esophagus to become narrowed, develop rings, or form abscesses, which hinders its normal function. Over time, untreated inflammation can lead to scarring and narrowing, making swallowing progressively difficult.
Symptoms of allergic esophagitis can vary significantly by age. Infants and toddlers might experience feeding difficulties, vomiting, or poor weight gain. Older children and adults commonly report trouble swallowing, often referred to as dysphagia, and food getting stuck in the throat, known as impaction. Other symptoms can include chest pain that might not respond to antacids, heartburn, abdominal pain, and regurgitation. These symptoms can be chronic or occur in flare-ups.
Allergic esophagitis is distinct from gastroesophageal reflux disease (GERD), despite sharing some similar symptoms like heartburn and difficulty swallowing. GERD is caused by stomach acid backing up into the esophagus due to a malfunctioning muscle, while allergic esophagitis is an immune condition triggered by an allergic response. In EoE, a large number of eosinophils multiply in the esophagus lining, whereas in GERD, if eosinophils are present, they are in much smaller numbers. Distinguishing between the two is important for appropriate treatment, as therapies for GERD, such as anti-acid medications, may not fully resolve EoE symptoms.
Identifying Common Triggers
Allergic esophagitis is primarily triggered by an immune system overreaction to certain substances, commonly food and environmental allergens. Research suggests that both genetic and environmental factors contribute to the development of this condition.
Common food allergens that can trigger allergic esophagitis include cow’s milk, wheat, soy, and eggs. Other food triggers are peanuts, tree nuts, fish, and shellfish.
Environmental allergens also play a role. Pollen and dust mites are examples of airborne allergens that can contribute to the condition. Some patients experience worsening symptoms during pollen seasons, such as spring or fall, suggesting a connection between inhaled allergens and esophageal inflammation.
Diagnosing Allergic Esophagitis
The diagnosis of allergic esophagitis requires a thorough evaluation, as its symptoms can overlap with other conditions. The primary method for confirming diagnosis is an upper endoscopy with biopsies of the esophagus. During an endoscopy, a thin, flexible tube with a camera is inserted down the throat to visually examine the esophagus for signs of inflammation, such as rings, narrowing, or white spots. Tissue samples are then collected from different areas of the esophagus.
These biopsy samples are then examined under a microscope to count the number of eosinophils present in the esophageal tissue. A diagnosis of allergic esophagitis is confirmed if the biopsy reveals 15 or more eosinophils per high-power field. This histological finding, combined with characteristic symptoms, helps differentiate allergic esophagitis from other esophageal disorders.
Allergy testing is a component of the diagnostic workup to identify potential triggers, though its accuracy in predicting EoE triggers can vary. Skin prick tests involve placing small amounts of allergen extracts on the skin and observing for a localized reaction, indicating an immediate-type allergy. Patch tests involve taping small amounts of fresh food to the skin for 48 hours, with results read at 72 hours, to look for delayed reactions. However, these tests may not always be perfectly accurate in identifying specific EoE triggers, with possibilities of false positives or negatives.
Elimination diets are also used in the diagnostic process to identify food triggers. These diets involve systematically removing certain foods, common allergens like milk, wheat, soy, egg, peanuts, tree nuts, and fish/shellfish, for about six weeks. After the elimination period, an endoscopy with biopsies is performed to assess for resolution of inflammation. If the inflammation has subsided, foods are then reintroduced one at a time, with subsequent endoscopies and biopsies, to pinpoint the specific food(s) that trigger the reaction in the esophagus.
Treatment and Management Approaches
Managing allergic esophagitis involves several strategies, including dietary interventions, pharmacological treatments, and other therapeutic options. The choice of treatment can depend on factors like the patient’s age, disease presentation, and personal preferences.
Dietary interventions are a common and effective approach for many individuals with allergic esophagitis. One method is the empiric six-food elimination diet, which involves removing the most common food allergens, such as milk, wheat, soy, egg, peanuts/tree nuts, and fish/shellfish, from the diet for about six weeks. If symptoms improve and esophageal inflammation resolves, foods are then gradually reintroduced one by one, with follow-up endoscopies and biopsies, to identify the specific trigger foods. Another option is an elemental diet, where individuals consume only an amino acid-based formula, which is highly effective in achieving remission, particularly in children, with success rates often exceeding 90%. However, elemental diets can be challenging to adhere to due to their restrictive nature.
Pharmacological treatments also play a significant role in managing allergic esophagitis. Proton pump inhibitors (PPIs) are oral medications that reduce stomach acid and are often prescribed, even though they are not specifically approved for allergic esophagitis by the FDA. They can help reduce inflammation and improve symptoms in some patients. Topical corticosteroids, typically repurposed from asthma medications, are swallowed to deliver the medication directly to the esophagus. These medications, such as budesonide or fluticasone propionate, work by reducing the number of eosinophils and decreasing inflammation in the esophageal tissue. New formulations, including oral suspensions and disintegrating tablets, are being developed to improve delivery.
Other therapeutic approaches include esophageal dilation if esophageal narrowing, known as strictures, persists despite medical or dietary therapies. This procedure involves gently stretching the narrowed areas of the esophagus to improve swallowing. Novel biologic agents, such as monoclonal antibodies, are under investigation as potential future treatments. These therapies, administered via subcutaneous injections or intravenous infusions, target specific inflammatory pathways involved in allergic esophagitis and show promising results in clinical trials.