Causes of Eosinophilic Esophagitis

Eosinophilic esophagitis, or EoE, used to be considered a rare disorder. However, with better testing methods and better understanding of the differences between GERD and EoE, it is now considered a common disorder for children and adults with swallowing problems. It is unclear if the prevalence of EoE is increasing or we have just become more aware of eosinophilic esophagitis.

Eosinophilic esophagitis is diagnosed by getting a biopsy of the esophagus and seeing 15 eosinophils under a high-power field microscope. Eosinophils are white blood cells (part of our immune system) that can be associated with inflammation and related to allergies. Understanding of EoE was initially slow, as it was associated with another form of reflux disease and solely treated with proton-pump inhibitors ( a type of medication for reflux disease), like Prilosec.

Prevalence and Symptoms

There is still ongoing research to help better determine both the prevalence as well as the risk factors associated with eosinophilic esophagitis. Men appear to be 3 times more likely than women to have EoE and can be found in children, young adults, as well as adults. The most common complaints that people have when seeking medical attention are:

• Difficulty swallowing (dysphagia)
• Heartburn
• Indigestion

Can Acid Reflux Cause Eosinophilic Esophagitis?

Initial thoughts around causation of eosinophilic esophagitis included damage of the esophagus caused by GERD or acid reflux from the stomach into the esophagus. The acid would damage the lining of the esophagus and allow eosinophils to invade. It wasn’t until the mid-1990s when this method started to be discredited. GERD is no longer believed to be the cause of EoE.

Environmental Risk Factors

Environmental factors have been identified as a possible factor in acquiring eosinophilic esophagitis. The rationale for this is also similar to environmental risk factors associated with asthma and inflammatory skin disorders. It is thought that not having enough exposure to bacteria and other microbes early in life may be an underlying cause of EoE. Situations that may limit infants to an appropriate amount of bacteria include:

• Cesarean section vs vaginal delivery
• Premature birth
• Early need for antibiotics during infancy
• Formula-fed vs breast-fed
• Living in a low population density area

During the course a pregnancy, your fetus has either a sterile gut (common belief, but a little bit of controversy over this) or very minimal exposure to bacteria. During a vaginal delivery, your baby becomes exposed to bacteria that will serve as an early start to the development of proper intestinal bacteria. This exposure does not occur during a cesarean section. It is important to realize that there are many good reasons to have a cesarean section and proper method of delivery should be discussed with your obstetrician.

Genetic Risk Factors

Genetic research is a continually evolving field of study. In relation to eosinophilic esophagitis, there are several things to consider in relation to genetics. There are studies that show a mildly increased risk for having EoE if a sibling or parent has the disease. About 2 in 100 families had familial risk, however environmental factors appeared to have a stronger correlation. This means that the family risk may have actually been related to environmental factors listed above.

There is, however, research that has identified genes that affect your body's immune response that may predispose you to acquire eosinophilic esophagitis:

• Impairment in the esophageal lining
• Acute allergic inflammation
• Chronic inflammation

Impairment in the esophageal lining allows for increased eosinophil recruitment to the esophagus when exposed to allergens. Acute inflammation related to eosinophilic esophagitis creates circular rings with trenches between the rings. There tends to also be fluid that leaks from the tissue as a result of the inflammation, called an exudate. Long-term, or chronic, inflammation eventually leads to fibrosis, or a thickening or scarring that narrows the esophagus. Fibrosis is one of the reasons why you may have food become stuck in your esophagus if you have EoE.

Allergen Risk Factors

One of the main identified risk factors for the development of eosinophilic esophagitis is allergies to foods. In cases of food allergies, your ENT can assist you in the dietary management of your symptoms. Common foods associated with EoE include:

• Dairy products
• Egg
• Soy
• Wheat

Environmental allergies can also play a role in the development of EoE. Common environmental risk factors include allergies to:

• Dust mites
• Animal dander
• Pollen
• Molds

You may notice that your EoE symptoms become worse during times of high pollen count. You can see an allergist for further testing to clarify allergies that may be worsening your symptoms. If you have worsening EoE symptoms due to environmental allergens, It is important to try to remove these allergens from your home.