[Blue baby syndrome: the source of the truth]

Methemoglobinemia is a rare disorder preferentially affecting children. The outcome may be dramatic when the disorder remains unidentified, however early recognition using unspecific exams allows prompt therapy. We report the case of a 14-month-old baby who presented with a sudden access of cyanosis resulting from acute methemoglobinemia. Careful investigation identified contamination of familial food by an excess of nitrates related to the use of well water from rural location.