Esophagitis is an increasingly diagnosed disease. Patients with gastroesophagic reflux, dysphagia, vomiting or abdominal pain, with a torpid response to the treatment, could be suffering from it.A 37 year-old male patient with background of gastroesophagic reflux and dysphagia for solids since 2002, self-limited diarrhea episodes and intolerance to alcoholic drinks due to epigastric pain. Skin prick tests, specific IgE, histamine release test and basophil activation test were carried out.Skin prick test to the usual allergens with negative result; prick-prick tests to egg white and yolk, milk and apple with positive result to egg white; total serum IgE within normal levels, specific IgE to egg white with positive result; histamine release test (HRT) and basophil activation test (BAT) with positive result to egg white and yolk.The patient was diagnosed eosinophilic esophagitis. The commercial food extracts have a great variability in their allergenic composition, which could result in false negative results in the prick test. Prick-prick with the natural food is a more sensitive technique than prick in the diagnosis of food allergy. There are other useful in vitro techniques, apart from specific IgE, in the diagnosis of food allergy. In our case, an exclusion diet of the involved food was more effective than other treatments for remission of the symptoms.