Food allergy and eosinophilic esophagitis are a substantial and evolving public health issue. Clinicians should know the relationship between these diseases and how one may predispose to the other. This can help minimize misdiagnosis.

The objective of this study was to assess esophageal eosinophilia and eosinophilic esophagitis frequency in patients with persistent cow's milk allergy and anaphylaxis manifestations.

Patients with persistent cow's milk allergy with anaphylaxis manifestations were enrolled from 2012 through 2016 at the São Paulo University Hospital, Brazil. All of them were submitted to endoscopy despite the presence or absence of gastrointestinal symptoms. Demographics data, atopic comorbidities, medication use, endoscopic findings, and esophageal eosinophilia frequency were evaluated.

Eighty-nine patients were selected. The median age was 8 years. It was observed that 34 of 89 patients (38.2%; 95% confidence interval [CI]: 28.14%-49.16%) presented with esophageal eosinophilia. Five patients (7.1%) presented proton pump inhibitor-responsive esophageal eosinophilia, and 10 patients (14.2%) presented eosinophilic esophagitis. We found that 29.4% were asymptomatic patients, 23.5% had nonspecific symptoms, 23.5% had persistent typical symptoms, and 23.5% had intermittent typical symptoms. There was an association with inflammatory endoscopy findings in 21 patients (61.7%).

This description demands scientific attention because it is the highest frequency of esophageal eosinophilia yet described in a group of patients with cow's milk allergy presenting with anaphylaxis. Eosinophilic esophagitis is a condition that can coexist “silently” with an IgE-mediated food allergy and is most often underestimated and underdiagnosed.