In the early 1990s, doctors began to describe a new condition that affects the esophagus in patients with a predisposition to allergies, including food allergies, asthma and eczema, and who had difficulty swallowing. Today we call this condition eosinophilic esophagitis (EoE).
What is EoE?
EoE is an allergic inflammation of the esophagus that causes various symptoms. Adolescents and adults usually experience difficulty in swallowing, sometimes with the feeling that food moves too slowly through the esophagus and stomach. In some cases, food even gets stuck (and it may be necessary to remove it urgently). Children and some adults mainly experience reflux symptoms and abdominal pain instead of having difficulty swallowing.
In most cases, EoE develops as an allergic reaction to certain foods, including wheat, milk, egg, soy, nuts and seafood. If it is not properly diagnosed and treated, EoE can lead to permanent scarring or narrowing (narrowing of the esophagus).
How is EoE diagnosed?
When EoE is suspected, the first test is generally an upper endoscopy, where a flexible tube with a small camera and a lamp at one end is used to examine the esophagus. The endoscopy usually reveals characteristic features of EoE, such as concentric rings and linear front or vertical lines, as well as small white spots or plaques.
The diagnosis is confirmed when biopsies of the esophagus reveal the characteristic increase in eosinophils. Eosinophils are a relatively rare type of immune cells that play a prominent role in allergic diseases, including EoE and asthma.
How often does EoE occur?
EoE can affect both men and women of any age, but it appears to be most common among men in their thirties and forties. It is estimated that EoE can affect up to one in 2000 adults in the US, and there are indications that the number has increased. A recent overview of nearly 30 investigations in Europe and North America has shown that the number of new EoE cases has gradually increased, especially since the early 2000s.
The increase in EoE cases may partly be due to a greater awareness of the condition and a wider use of endoscopy. But a number of studies have confirmed a real rise in the incidence of the disease.
Why should EoE be emerging?
The exact reasons for the emergence of EoE are unknown, and it is above all a mystery that in many cases EoE is the result of an allergic sensitivity to a food that is well tolerated up to that point.
There are several hypotheses about why EoE is increasing. Many of them refer back to the idea that EoE and other allergic and autoimmune diseases seem to correlate with reduced exposure to microbes and infections. Possible explanations that have been investigated include:
- The hygiene hypothesis: are fewer infections in children the same as more allergic diseases?
- Microbial dysbiosis: have modern / western food and lifestyle changed our microbiome?
- Environmental factors: can changes in food production, genetic modification of crops, chemical additives, food processing and pollutants play a role?
- Decreasing frequency of H. pylori infection: can this common stomach bacterium (a common cause of stomach ulcers) be protective against some allergic diseases?
- Increasing frequency of gastroesophageal reflux disease (GERD): can acid reflux break the barrier of the esophagus and food allergens stimulate the immune system?
- Increasing use of acid suppressing drugs: does the use of gastric acid inhibitors, especially early in life, change the microbes in the esophagus or does it somehow alter the risk of subsequent food allergies?
How is EoE treated?
There are currently no FDA approved treatments for EoE. Most people are initially treated with a proton pump inhibitor (PPI) antacid, which dissolves EoE in up to half of the cases. If this does not work, try a mild topical steroid or identification and elimination of specific food triggers.
When steroids are used to treat EoE, they are generally in a liquid formulation that is swallowed rather than inhaled as they would be for asthma. Swallowed steroids act locally on the esophagus and are minimally absorbed by the gastrointestinal tract. Although steroids are generally safe and effective for EoE, they do not lead to a long-term cure because the disease usually returns as long as patients continue to eat food that causes the underlying allergic reaction.
Patients can also choose to identify their food trigger and remove it from the diet, and this represents a more definitive treatment approach. Unfortunately, the currently available allergy test does not accurately predict the foods that cause EoE. Trigger foods must generally be identified using a process of food elimination and reintroduction. Wheat and dairy products are the two most common triggers for EoE and patients often start eliminating these two foods for about eight weeks. At that time, their symptoms are reassessed and they also undergo repeated endoscopy with biopsies to determine whether the eosinophils have disappeared in response to dietary changes.
Various drug therapies are coming. These include better formulations of steroids and biological drugs that reduce the activity of eosinophils.
If you have trouble swallowing or if you have had food that gets stuck in the esophagus, especially if you have other allergic diseases, talk to your doctor. Unrecognized or untreated EoE can cause permanent damage to your esophagus.
Go to the American Partnership for Eosinophilic Disorders for more information or for more information about strategies for living with EoE.