• A person’s genetics, environment, and immune system all likely contribute to the development of eosinophilic esophagitis (EoE).
• Allergic reactions to food and other substances may partially cause EoE, but it’s unclear how and to what extent.
• After evaluation and testing, an allergist may provide recommendations that could improve your EoE.

Doctors and researchers aren’t quite sure what causes eosinophilic esophagitis, but research shows that allergies — along with genetics — may play a role. Allergic reactions occur when your immune system overreacts to certain substances — such as animal dander, dust mites, or certain foods. Treating allergies may help in relieving EoE symptoms. However, more research on the connection between EoE and allergies is necessary to determine how these conditions are linked.

The Role of Eosinophils in EoE

One of the defining features of EoE is the presence of specialized white blood cells — known as eosinophils — in the esophagus. Eosinophils play an important role in your immune system, helping to trap and kill parasites and bacteria. They also release chemicals that help create inflammation to fight infections.

Eosinophils also play a role in allergic reactions. These occur when your immune system overreacts to certain substances in the environment or your food, known as allergens. As a result, your immune cells create inflammation to try to “fight” the substance, leading to allergy symptoms. The symptoms you experience will depend on the type of allergy you have.

Normally, eosinophils aren’t found in the esophageal tissues. However, in EoE, an immune system response appears to involve sending eosinophils to the esophagus and releasing chemicals that result in inflammation. Over time, this inflammation damages your esophagus, leading to symptoms of EoE such as:

• Food impaction (food stuck in your esophagus)
• Dysphagia (trouble swallowing)
• Strictures (narrowing of your esophagus)
• Abdominal pain
• Acid reflux (excess stomach acid) or heartburn

Allergies and EoE

Since EoE is a chronic immune condition, doctors and researchers have looked to allergies as a potential cause. They believe that food allergies — along with environmental and seasonal allergies — may cause EoE, but it’s unclear how and to what extent.

Food Allergies

Food allergies affect around 7.6 percent of children and 10.8 percent of adults in the United States. These allergies result from an overreaction of the immune system caused by specialized antibodies called immunoglobulin E (IgE). These antibodies bind to other immune cells that release a chemical called histamine. Usually, histamine causes symptoms immediately, such as:

• Wheezing and trouble breathing
• Hives
• Itchy skin
• Vomiting
• Diarrhea

In people with EoE, however, food allergy symptoms take days to appear. Research also shows that IgE doesn’t seem to play a central role in these allergies, making the role of food allergies in EoE even more puzzling.

There is some evidence that food allergies may contribute to EoE. For example, more than 90 percent of people with EoE see their symptoms improve when following certain diets. One such diet is the elemental diet, designed to prevent your immune system from reacting to certain foods and calm inflammation. The elemental diet uses meal-replacement shakes containing necessary nutrients that are broken down into the most basic elements, or food-building blocks. These shakes include amino acids, small sugars, and fats to replace proteins, carbohydrates, and fats.

Many people also improve their EoE symptoms by following an elimination diet. With this diet, you stop eating specific foods known to cause allergies for two to four weeks. Then you add a new food back in during what’s called a challenge period, typically every three days. By adding each food in one at a time, you can figure out which ones are making your EoE symptoms worse.

Nearly 90 percent of all food allergies are caused by these eight foods:

• Eggs
• Fish
• Milk
• Peanuts
• Shellfish
• Soy
• Tree nuts
• Wheat

Your doctor may recommend a four- or six-food elimination diet, both of which have been studied for treating EoE. The four most common food allergens studied in EoE are wheat, soy, egg, and cow’s milk. The six-food elimination diet also includes nuts and fish/shellfish. Many people’s EoE symptoms return if they begin eating triggering foods again on a regular basis.

Studies have also found some genes involved in food allergies, particularly in children. These genes provide instructions for making proteins involved in maintaining a healthy skin barrier and in making IgE antibodies. They have also been found to play a role in atopic dermatitis (the most common form of eczema), a skin condition that’s common in people with EoE.

Seasonal and Environmental Allergies

Research also shows that seasonal and environmental allergies may cause or play a role in EoE. Around 50 percent of people with EoE have asthma or allergic rhinitis (seasonal allergies). Examples of allergens that may trigger or worsen EoE include:

• Pollen from grasses, trees, and weeds
• Pet dander (skin flakes)
• Dust mites
• Molds

Many people with these allergies notice that their EoE symptoms worsen in spring when pollen levels are high, or in fall when mold spore levels are high. After a person with allergies breathes them in through their mouth or nose, the spores come in contact with the esophagus, causing eosinophils to release inflammation-causing chemicals.

Biopsies (tissue samples) taken from the esophagus show that people with seasonal allergies have more eosinophils in their esophageal tissues in the spring than in the winter. Other allergy symptoms you may experience include a runny or stuffy nose or itchy, watery eyes.

Allergy Testing and EoE

If your doctor thinks your allergies may be contributing to your EoE, they may refer you to an allergy specialist who may run some tests. These can include seasonal and food allergy tests such as skin prick tests and blood tests to look for IgE antibodies for specific food allergens.

A skin prick test, also known as a scratch or puncture test, is used to look for allergies to certain substances. This test tells your doctor if you’re allergic to certain foods, pollen, pet dander, mold, or dust mites. First, a doctor will use a lancet (small needle) to prick liquid extracts of potential allergens into your skin. After 15 minutes, your doctor will look for red, itchy bumps on your skin that show you’ve had an allergic reaction.

Other tests may look for an allergic reaction over the course of several days. Nearly 70 percent of children and 50 percent to 60 percent of adults with EoE have positive skin prick test results for food allergens.

A doctor may also perform a serum allergy test to measure levels of IgE antibodies in your bloodstream. Your doctor will take a small blood sample, which is then analyzed for IgE. A specific IgE test can look for a reaction toward a particular allergen, typically a food allergen.

Although all of these tests are generally accurate for finding food allergies caused by IgE antibodies, doctors and researchers know that allergies — especially food allergies in EoE — aren’t directly related to IgE levels. Therefore, these tests may give inaccurate results, especially if it takes days for the reaction to show. Nonetheless, they can still help guide doctors toward a potential allergy and treatment plan.

Talk to Your Doctor

If you’re living with allergies, talk to your doctor or gastroenterologist about how they may affect your EoE. They may also recommend you make an appointment with an allergist who can test you for specific allergies and make treatment recommendations. Together, your gastroenterologist and allergist can help you better manage your EoE.

Talk With Others Who Understand

On myEoEcenter, the site for people with eosinophilic esophagitis and their loved ones, people come together to learn about EoE and share their stories with others who understand life with EoE.

Do you have allergies and EoE? What treatments has your gastroenterologist or allergist recommended to help? Share your experience in the comments below.