OIT Can Continue Even if EoE Develops, Researchers Say

Oral immunotherapy (OIT) is sometimes used in individuals with food allergy mediated by immunoglobulin E, but one possible side effect is the development of eosinophilic esophagitis (EoE).

A recent study attempted to determine the prevalence of EoE in a group of patients allergic to milk or egg and undergoing OIT to both, as well as describe its management and treatment pathway.

The authors, from a hospital in Spain, cited a previous meta-analysis showing an EoE prevalence of 2.7% after OIT, as well as their own group’s statistics showing that EoE was found in 4.6% of patients using OIT.

In this study, 192 children were treated with OIT (149 with cow's milk and 43 with egg) for confirmed food allergy from 2006 to 2021. They were monitored for gastrointestinal distress at every visit and none of the patients presented with digestive symptoms before OIT.

Of the 192 patients, 23 underwent endoscopy and 16 had histologically proven EoE (8.3%). Diagnosis was made if a biopsy showed at least 15 eosinophils per high power field (eos/hpf), and treatment response was defined as less than 15 eos/hpf in all esophageal biopsies upon repeat endoscopy done 8 to 12 weeks after baseline endoscopy.

The children who developed EoE were mostly male (68%) and aged 3 to 18 years with an atopic history, including asthma, atopic dermatitis, and allergic rhinoconjunctivitis. Ten of the children were allergic to multiple foods.

Of the 16 patients with proven EoE, 11 were receiving milk OIT, 4 were receiving egg OIT, and 1 child was receiving both.

EoE was diagnosed in 2 cases during induction phase, due to persistent vomiting. The others case developed during the maintenance phase of OIT after a median time of 46 (range, 24-78) months.

Abdominal pain was the most frequent symptom (56%), followed by dysphagia (50%) and vomiting (31%). One patients received their diagnosis following an upper gastrointestinal bleeding due to food impaction.

The 16 patients kept the allergenic food in their diet and began medical treatment, and results showed:

• 14 of the 16 were treated with high-dose proton pump inhibitors (PPIs), with 10 reaching short-term remission (71%)
• 9 patients had an endoscopy after long-term follow-up, with 6 of them maintaining remission (66%), with a median time of monitoring of 54  (range, 30-84) months
• 8 patients were treated with swallowed steroids (6 without short- or long-term remission with PPIs and 2 as first-line treatment), with all achieving short-term remission
• 5 patients had a long-term follow-up maintaining remission, with a median period of 30 (range, 10-45) months

The researchers found a prevalence of EoE in their patients undergoing OIT of 8.3%, higher than those in other reported studies, which they said might be explained by the close long-term monitoring in the follow-up phase.

In addition, an invasive procedure like an endoscopy is not indicated in asymptomatic patients before starting OIT, so it is possible that some patients already had preexisting subclinical disease. Also, esophageal eosinophilia has been noted in patients prior to the beginning of OIT. Although eosinophilia is not usually linked with clinical symptoms, the authors said it is possible that it could progress to the point of causing symptoms.

“Although EoE development in the context of OIT could be a reason to discontinue OIT, there is no consensus regarding management of such patients,” wrote the authors, who noted that many patients are reluctant to stop eating foods to which they are allergic.

The researchers called for close monitoring of these patients and said although treatment should be individualized, they recommended trying to maintain OIT in order to improve quality of life and to avoid future anaphylactic reactions if the allergic food is removed from the diet for a period of time and later consumed.

Reference

García Vega M, Fernández-Fernández S, Echeverría Zudaire L, et al. Long-term medical treatment efficacy in patients with eosinophilic oesophagitis and oral food immunotherapy. Clin Exp Allergy. Published online August 22, 2022. doi:10.1111/cea.14219