Eosinophilic (e-o-sin-o-FILL-ik) esophagitis (EoE) is a recognized chronic allergic/immune condition of the esophagus. The esophagus is the tube that sends food from the mouth to the stomach. In EoE, large numbers of white blood cells called eosinophils are found in the inner lining of the esophagus. Eosinophils can release substances into surrounding tissues that cause inflammation. Normally there are no eosinophils in the esophagus. A person with EoE will have inflammation and increased numbers of eosinophils in the esophagus. The chronic inflammation of EoE leads to symptoms.
The symptoms of EoE vary with age. Infants and toddlers may refuse to eat or not grow properly. School-age children often have decreased appetite, recurring abdominal pain, and trouble swallowing or vomiting. Teenagers and adults can have the same symptoms, but often have difficulty swallowing dry or dense, solid foods. The difficulty swallowing occurs because the esophagus is inflamed, and in severe cases, because the esophagus narrows to the point that food gets stuck. Food firmly stuck in the esophagus is called a “food impaction,” which can be a medical emergency if the food does not go down the esophagus into the stomach or is not vomited up relatively quickly.
Allergists and gastroenterologists are seeing many more patients with EoE. This is due to an increased incidence of EoE and greater physician awareness. EoE is considered to be a chronic condition that can be medically managed, but is not outgrown.
Eosinophils can be found in the esophageal tissue in diseases other than EoE. One common example is acid reflux disease. Other diseases that can cause eosinophils to be in the esophagus must be ruled out before EoE can be accurately diagnosed.
Currently, performing an upper endoscopy with biopsies of the esophagus is necessary to diagnose EoE. An endoscopy is a medical procedure where a flexible tube containing a light source and a camera lens is passed down the esophagus so your doctor can see if your esophagus is inflamed. Small pieces of esophageal tissue the size of the tip of a pen (biopsies) are taken to be examined under the microscope for the presence of eosinophils and for signs of inflammation.
There are certain criteria for diagnosing EoE that are followed by allergists, gastroenterologists and pathologists. These include symptoms consistent with EoE in combination with findings on the upper endoscopy and upon examination of the esophageal tissue biopsies by a pathologist that confirm EoE.
The majority of patients with EoE are atopic. An atopic person is someone who has symptoms of one or more allergic disorders. These include asthma, allergic rhinitis, atopic dermatitis (eczema) and food allergy. EoE has occasionally been shown to occur in other family members. Because many patients with EoE are atopic, they may be seen first by an allergist who suspects the diagnosis and refers them to a gastroenterologist for confirmation of EoE. Alternatively, if the diagnosis of EoE is made by a gastroenterologist, you may be referred to an allergist for allergy testing. It will provide you, your family and the gastroenterologist with information so that any allergic aspects of EoE can be properly treated. It may also help plan diet therapy and eventual reintroduction of foods to your diet.
Environmental allergies to substances such as pollens, animals, dust mites and molds possibly play a role in EoE. For some patients, it may seem like their EoE is worse during pollen seasons. Allergy testing for these common environmental allergies is often part of the EoE evaluation.
Adverse immune responses to food are the main cause of EoE in a large number of patients. Allergists are experts in evaluating and treating EoE related to food allergies. However, the relationship between food allergy and EoE is complex. In classical Immunoglobulin E (IgE)-mediated food allergy, the triggers are easily diagnosed by a history of a severe allergic reaction such as hives and vomiting within minutes after ingestion of the offending food. In EoE, it is more difficult to establish the role of foods because the reactions are delayed, and can develop over days, making it harder to pinpoint a specific food as the trigger. Allergists may perform different allergy tests to identify sensitization to foods that might play a role in causing EoE. Foods such as dairy products, egg, soy and wheat are recognized as the most common triggers for EoE. However, conventional allergy tests often fail to detect sensitivity to the foods causing EoE. This is because most food allergy reactions in EoE are delayed and caused primarily by immune mechanisms other than classical IgE-mediated food allergy. A person with EoE may have one or more foods triggering their EoE. Once the causative food(s) is (are) identified and removed from a person’s diet, esophageal inflammation and symptoms generally improve in a few weeks. Thus, removal of suspected food(s) from the diet followed by a decrease in symptoms and esophageal inflammation is necessary to prove that the food(s) is (are) causing EoE.
Allergy skin testing provides the allergist with specific information about what you are and are not sensitized to. Patients with allergies make an allergy antibody called IgE. When patients with IgE for a particular allergen have tiny amounts of that allergen put into their skin (prick skin test), an area of swelling and redness forms within about 15 minutes at the site where the skin prick test was done. However, these tests have limited use in identifying foods causing EoE because EoE is not caused by IgE antibodies.
Sometimes an allergist may do a blood test (called a serum specific immune assay) to see if you are sensitized to a specific allergen. This test detects IgE circulating in the blood stream directed against an allergen and can be helpful in certain conditions linked to IgE-mediated food allergies. As previously noted, there are limitations to both prick skin testing and blood testing for IgE-mediated sensitivities in EoE in regard to accurately identifying foods that cause EoE. Unfortunately, serum specific immune assays that check for IgG antibodies to a large number of foods are also not helpful in identifying the foods that cause EoE.
Eliminating foods based on the result of prick skin tests alone often does not improve EoE. Food patch testing is another type of allergy test that was previously thought to be useful in identifying foods triggering EoE in some patients. The patch test is done by placing a small amount of a fresh food in a small aluminum chamber called a Finn chamber. The Finn chamber is then taped on the person’s back. The food in the chamber stays in contact with the skin for 48 hours. It is then removed and the allergist reads the results at 72 hours. Areas of skin that came in contact with the food and became inflamed were thought to possibly identify a positive delayed reaction to the food. Patch testing is no longer recommended for routine use in the evaluation of EoE.It is important to understand that skin prick tests, allergy blood tests and food patch tests can have false positive tests. This means that these tests may suggest you are sensitized to a food that you can tolerate and does not cause your EoE. They can also have false negative results, meaning that the test is negative to a food that is actually causing EoE. Elimination diets, where foods suspected of causing EoE are removed from the diet, are an effective method for treating EoE (see below). A small percentage of people develop an IgE-mediated food allergy to a food that has been removed from their diet for a long time to see if it causes their EoE. These people can have an immediate allergic reaction when they eat the food again. Using prick skin tests and/or blood tests to detect IgE-mediated sensitivity to foods, your allergist can help determine when a food can be safely reintroduced to your diet following its elimination for EoE.
If you are noted to have specific food sensitivities after prick skin testing your doctor may remove specific foods from your diet to see if there is a reduction in EoE symptoms. In some individuals this helps control their EoE, though this type of diet has not shown to be very successful in research studies.
Eliminating the major food allergens from the diet is considered an acceptable treatment of EoE. The foods excluded usually include dairy, egg, wheat, soy, peanut/tree nuts and fish/shellfish. These diets have been shown to be very helpful in treating EoE, although they can be very difficult to follow, especially without the help of a dietitian with experience in dealing with EoE. Foods are typically added back one at a time with follow up endoscopies to help determine which specific foods are causing EoE.
In this strict elimination diet, all sources of allergens are removed from the diet. The patient receives their nutrition from an amino acid formula alone or sometimes while allowing one to two simple foods chosen based on their low likelihood to trigger EoE. All other foods are removed from the diet. A feeding tube may be needed in very young children treated with this diet, since they are often unable to drink enough of the formula to get adequate nutrition. This approach is generally reserved for children with multiple food allergies who have not responded to other forms of treatment.
No medications are currently approved by the U.S. Food and Drug Administration (FDA) to treat EoE, until now! Dupixent, a biologic agent already approved for eczema, asthma, and nasal polyps, is now approved as a once-a-week home injection for those 12 and older.
Other medications have been shown to reduce the number of eosinophils in the esophagus and improve symptoms. Proton pump inhibitors (PPIs), which reduce acid production in the stomach have also been found to be able to reduce esophageal inflammation in some patients with EoE. Thus, PPIs are often used as a first treatment for EoE. Some patients respond well to PPIs and have a large decrease in the number of eosinophils and inflammation when a follow-up upper endoscopy with biopsies is done. However, not all patients respond to PPIs, and other forms of therapy such as swallowed topical corticosteroids or elimination diets are considered. Careful monitoring by a physician knowledgeable in treating EoE is very important.
Corticosteroids, which control inflammation, are helpful medications for treating EoE. Swallowing small doses of corticosteroids so they come into contact with and treat the inner lining of the esophagus is the most common treatment. Different forms of swallowed corticosteroids are available. Once esophageal inflammation is adequately controlled, the dose of swallowed corticosteroid is decreased to the smallest dose necessary to maintain control in order to reduce the risk of steroid side effects.
EoE is a complex disorder. It’s important for patients to listen to their gastroenterologist for advice on managing EoE and figuring out when endoscopies are needed to check to see if the condition is getting better or worse. Patients also need to work closely with their allergist/immunologist to find out if allergies are playing a role. An allergist/immunologist will also be able to tell if you need to avoid any foods and can help you manage related problems like asthma, eczema and allergic rhinitis. It is important that your gastroenterologist and allergist work together and agree on how to take care of your EoE. If you are following a diet to treat your EoE, working with a dietitian who knows about elimination diets used to treat EoE is highly recommended.
When you first find out you have EoE, it can be overwhelming. Families often benefit from participating in support groups and organizations. Visit the American Partnership for Eosinophilic Disorders (APFED) and Campaign Urging Research for Eosinophilic Disease (CURED). These are two lay organizations that provide valuable, reliable resources and have ongoing relationships with the AAAAI.