Eosinophilic esophagitis (EoE) is a benign, chronic disorder of the esophagus characterized by intermittent solid food dysphagia and impaction, as well as chest pain and heartburn. Left untreated, this disorder is also associated with esophageal remodeling and stricture formation.
Current guidelines recommend performing endoscopic biopsy to obtain four to six tissue samples from the esophageal mucosa to confirm diagnosis. A positive diagnosis is defined by eosinophilic infiltration of at least 15 eosinophils (eos) per high-power field (HPF).
Treatment of EoE is directed at reducing inflammation and reversing esophageal fibrosis that develops as a result of long-term inflammatory activity. Commonly used treatment options for EoE include dietary, pharmacologic and endoscopic intervention, each of which has known advantages and disadvantages:
- Elimination and elemental diets to decrease allergen exposure
- Advantages: no known associated risks, little long-term cost impact
- Disadvantages: time-consuming costly short-term evaluation; long-term dietary restrictions
- Include use of proton pump inhibitors (PPIs) as first line therapy for EoE, with at least one-third of patients having a histologic and symptomatic response
- Swallowed glucocorticoids effective in PPI failures
- Swallowed budesonide (2 mg bid) or fluticasone (880 mcg bid) effective at treating inflammation and symptom resolution in the vast majority of patients
- Effectiveness of anti-inflammatory treatment needs to be evaluated histologically
- Advantages: provide symptom relief and allow unrestricted diet
- Disadvantages: expensive; treatments don't address underlying cause of inflammation; potential associated risks.
- Esophageal dilation is the only treatment for esophageal strictures
- Advantages: provides effective relief from dysphagia
- Disadvantages: doesn't address underlying inflammation; potential associated risks include chest pain, the most common, and esophageal perforation, occurring in about 3 out of every 1,000 cases
Given that dietary therapy actually prevents esophageal inflammation, is associated with lower costs and has fewer known side effects than currently available pharmacologic and endoscopic interventions, this approach is gaining gradual acceptance as a treatment for EoE in both children and adults.
During a recent presentation at Mayo Clinic's Esophageal Diseases Course in Phoenix, Arizona, Mayo Clinic gastroenterologist Jeffrey A. Alexander, M.D., explained current research findings and clinical experience related to the use of elimination diets in the treatment of EoE.
Elimination diet overview
The six-food elimination diet (SFED) is the most frequently employed dietary therapy in patients with EoE. This diet typically trials the exclusion of wheat, milk, egg, nuts, soy, fish and shellfish.
An upper endoscopy and biopsy is performed after six weeks of the SFED diet. Responders then have a new food group reintroduced every two to four weeks. Esophageal histologic sampling is required repeatedly during the food reintroduction period, as it is the only way to determine which foods are triggering the inflammation.
Results obtained from two studies conducted in Chicago and Spain show that about 70 percent of patients showed symptomatic and histologic response after eliminating specific allergens from their diets. Multiple studies have found milk (60 percent) and wheat (30 percent) to be the most common food triggers. Some have suggested starting with a two-food or four-food restriction and advancing to the SFED in nonresponders.
Studies conducted at Mayo Clinic have tested a procedure that facilitates sampling of the esophagus without the need for endoscopy. This test uses a swallowed, dissolvable gelatin capsule that covers an esophageal sponge attached to a string. The string and sponge can be pulled out of the mouth after five minutes. "Studies using this alternative to endoscopy have yielded promising results, and the test is much-preferred by patients," explains Dr. Alexander.
Moving beyond the SFED
To advance the science of dietary therapy and allow dietary approaches to gain broader acceptance, Dr. Alexander says that researchers and clinicians must address several key questions:
- Can the recommended diet be maintained long term?
- Can we develop and refine noninvasive testing options to determine food triggers?
- Should we start with one- to four-food elimination diets?
- Is 15 eos/HPF the correct diagnostic threshold?
- Is a two-week elimination period long enough to determine dietary triggers?
"Although recent studies show positive results associated with six-food elimination diets, it's important to remember that many patients demonstrate difficulty complying with the time investment and long-term dietary constraints associated with this regimen," notes Dr. Alexander.
As new data about the efficacy of dietary strategies continue to become available, Dr. Alexander is eager to see dietary approaches continue to evolve and become adopted in the primary care clinical practice setting.