What is an Eosinophil?
Eosinophils, a type of white blood cell, are an important part of the immune system, helping us fight off certain types of infections, such as parasites. Many different problems can cause high numbers of eosinophils in the blood including allergies (food and environ-
mental), certain infections (caused by parasites), eosinophil associated gastrointestinal disorders, leukemia, and other problems. When eosinophils occur in higher than normal numbers in the body, without a known cause, an eosinophilic disorder may be present.
Eosinophilic disorders are further defined by the area of the body affected. For instance, eosinophilic esophagitis is associated with abnormally high numbers of eosinophils in the esophagus.
What is EE? Eosinophilic esophagitis (EE) is an allergic inflammatory disease characterized by elevated eosinophils in the esophagus EE is a newly recognized disease that over the past decade has been increasingly diagnosed in children and adults. This increase is thought to reflect an increase in diagnosis as well as a true increase in EE cases. Fortunately, the medical community is responding and new scientific information is emerging to guide management of this disorder, which often persists with ongoing or recurrent symptoms. Eosinophilic esophagitis is characterized by a large number of eosinophils and inflammation in the esophagus (the tube connecting the mouth to the stomach). These eosinophils persist despite treatment with acid blocking medicines. People with EE commonly have other allergic diseases such as rhinitis, asthma, and/or eczema. EE affects people of all ages and ethnic backgrounds. Males are more commonly affected than females. In certain families, there may be an inherited (genetic) tendency.
In individuals with EE, the eosinophils cause injury to the tissue in the esophagus. EE can be driven by food allergy or intolerance: most patients who eliminate food proteins from their diet (by drinking only an amino-acid based formula) improve.
Eosinophils are not normally present in the esophagus, although they may be found in other areas of the gastrointestinal tract. Diseases other than EE can cause eosinophils in the esophagus including gastroesophageal reflux diseases (GERD), food allergy, and inflammatory bowel disease. A gastroenterologist can diagnose EE based on clinical symptoms, number of eosinophils present, and tissue inflammation
What are the Symptoms of EE?
Symptoms vary from one individual to the next and may differ depending on age. Vomiting may occur more commonly in young children and difficulty swallowing in older individuals.
Common symptoms include:
Reflux that does not respond to usual therapy (medicines which stop acid production in the stomach)
Dysphagia (difficulty swallowing)
Food impactions (food gets stuck in the esophagus)
Nausea and Vomiting
Failure to thrive (poor growth, malnutrition, or weight loss) and poor appetite
How is EE Diagnosed?
At present, the only way to definitively diagnose EE is through endoscopy with biopsies. The endoscopy is often performed after treatment with reflux medications (acid suppressors) have failed to relieve the symptoms. During an upper endoscopy, the gastroenterologist looks at the esophagus, stomach, and duodenum (first part of the small bowel) through an endoscope (small tube inserted through the mouth) and takes multiple biopsies (small tissue samples) which a pathologist reviews under the microscope.
The gastroenterologist may be able to see a problem through the endoscope, but eosinophilic esophagitis may be present even if the esophagus looks normal to the doctor. That is why the biopsy samples are important to making the diagnosis of EE. A high number of eosinophils throughout the length of the (> 15 per high power field) suggest the diagnosis of EE. GERD also causes eosinophils in the esophagus, but typically far fewer and only in the part of the esophagus closest to the stomach. The pathologist will also look for tissue injury, inflammation, and thickening of the esophageal layers. With EE, the increased eosinophils are limited to the esophagus and not found in other areas of the intestinal tract. Once the diagnosis of EE is confirmed, food allergy testing is typically recommended to guide treatment. Skin prick testing to different foods is the most common type of allergy testing
The examples below are of endoscopic findings that may be seen in eosinophilic esophagitis*.
Furrows
Rings
White plaques
Images courtesy of Dr. Chris Liacouras, Children’s Hospital of Philadelphia.
Allergy Testing (skin prick, patch testing and RAST)
Once the diagnosis of EE is confirmed, allergy testing is typically requested. In many situations, avoiding ‘allergens’ that trigger the eosinophils will be effective treatment. The reactions to foods are not always ‘immediate hypersensitivity’ (IgE-mediated). This means that a food can be consumed with no obvious reaction to it, but over a period of days to weeks the eosinophils triggered by the food will cause inflammation and injury to the esophagus. For this reason, food logs (keeping track of foods and symptoms) may not identify the offending food. During food trials, an individual with EE may try introducing a new single food and waiting a few days to weeks before introducing another food. The skin testing will include skin prick testing and may also include patch testing (to look for delayed reactions).
Skin prick testing is for IgE- mediated reactions (‘immediate hypersensitivity’). Skin prick testing involves ‘scratching’ small amounts of pure food or environmental allergens into the skin. A ‘wheal’ (bump) and flare (redness) greater than the negative control indicates a positive test. Both a positive control (one that should cause a wheal and flare) and negative control (should not cause a wheal and flare) are used.
Skin patch testing can be used when testing for delayed food reactions. Skin patch testing is most commonly used to test for dermatologic (skin) reactions. When used for food reactions, small amounts of a pure food are placed in tiny cups, which are then taped to the back. The foods will be chosen based on the patient’s diet, previous reactions, and prior skin prick test results. The patches are removed after 48 hours and read at 72 hours.
Example of Patch Testing
RAST (Radioallergosorbent test) is not as helpful for identifying foods that cause EE. Instead, RAST may be used to confirm an immediate reaction to a food (for instance, hives following a peanut butter sandwich). RAST testing identifies IgE antibodies for a specific food.
EE is a relatively uncommon disorder that doctors may not encounter often. The diagnosis of EE is often delayed, sometimes for years, because of lack of awareness of these disorders.
Treatment • Dietary
• Medications
At present, the two main treatments recommended are dietary management and topical corticosteroids. A comprehensive allergic evaluation to foods and aeroallergens is recommended in the 2007 Consensus Recommendations for Diagnosis and Treatment.
Many children and adults with EE respond favorably to dietary treatments. The dietary restrictions are guided by food allergy testing and ‘fine-tuned’ with food trials once the symptoms have resolved.
Targeted Elimination diets, in which "positive" foods on allergy testing are removed from the diet, are one type of dietary treatment. An elimination diet may be the only treatment needed for some individuals with eosinophilic esophagitis.
Empiric Six-food elimination diet isanother type of elimination diet that has shown success in some EE patients. Instead of basing dietary elimination on skin testing, patients eliminate 6
common allergenic foods (milk, eggs, wheat, soy, peanuts/other nuts, fish/shellfish) regardless of the results of the allergy testing.
Learn more: Restricted Diets.pdf
Elemental diets, in which all sources of protein are removed from the diet, are another dietary therapy. An elemental diet includes only an amino acid formula (building blocks of protein), with no whole or partial proteins. Simple sugars, salt and oils are permitted on an elemental diet. Because these formulas are not palatable, the use of a strict elemental diet may require a feeding tube. Amino-acid based formulas are very expensive and are only sometimes covered by health insurance. Elemental diets are effective in treating most people with EE. Learn more: Elemental Diets
Children and adults who rely in part, or completely, on an elemental amino acid based formula may have a difficult time drinking enough of the formula. To maintain proper nutrition, some may require tube feedings directly into the stomach (enteral feeds). View an Illustration of an NG Tube Learn more: Living with Feeding Tubes.pdfFood trials involve adding back one ingredient at a time to one’s diet to determine specific foods causing a reaction. Food trials begin after symptoms resolve and eosinophils have cleared. Food trials are handled differently by different professionals, but may involve repeat endoscopies with biopsies as foods are introduced to determine which foods are ‘safe’ for an individual.
Medications
Medications for EE most commonly include steroids to control inflammation and suppress the eosinophils. Steroids can be taken orally or topically (swallowed asthma medicine). For many patients, swallowed topical corticosteroids (fluticasone, budesonide) have led to EE remission (improvement while on treatment), though their long-term use for maintenance treatment has not been studied. For some people on swallowed steroids, Candida (yeast infections of the mouth and esophagus) can be a side effect. Acid suppressors may also help symptoms in some patients with reflux.
For more detailed information on the treatment of EE and related disorders
Learn more: Treatment of EGID EE requires ongoing care
Patients with EE will require additional endoscopies to assess how the esophagus is responding to specific treatment. Physicians and scientists are working to discover other methods of monitoring and diagnosis. Novel medicines are also being tested that may help with future management of EE.
Prognosis
EE does not appear to limit life expectancy and there is currently no strong data suggesting EE causes cancer of the esophagus. In some patients, EE is complicated by the development of esophageal narrowing (strictures) which may cause food to lodge in the esophagus (impaction). It is not clear how long EE has to exist before strictures form. However, since the natural history of EE is only emerging, careful monitoring and long-term follow-up is advised. The initial diagnosis of EE can be overwhelming and often affects the entire family. A positive attitude and a focus on non-food activities go a long way in learning to live with EE. With proper treatment, individuals with EE can lead a normal life.
