Eosinophilic gastroenteritis is an uncommon condition that is characterized by infiltration of the gastrointestinal tract by eosinophils.
We report the case of a 24-year-old woman who presented 4 episodes of eosinophilic gastroenteritis. Skin prick tests and patch tests with different allergens were all negative. The patient’s eosinophil cationic protein (ECP) level was very high. Given that one of the most common causes of this condition is allergy to cow’s milk, ECP levels were determined during a diet with and without cow’s milk. ECP levels
were considerably elevated during the diet with milk, although they returned to normal values several months after milk was withdrawn.
The favorable clinical outcome and normalization of ECP levels point to a very probable association with cow’s milk in the eosinophilic gastroenteritis presented by our patient.

Key words: Food allergy. Eosinophil. Eosinophilic gastroenteritis. Eosinophil cationic protein.