Subclinical mastitis presenting as acute, unexplained, excessive crying in an afebrile 31-day-old female

We present a case of a 31-day-old female who presented with an acute, unexplained, episode of excessive crying. The patient had no history of fever and no fever on presentation. There was no evidence of skin erythema or swelling on presentation. Chest radiograph and computed tomography of the head were normal. Urinalysis and cerebral spinal fluid analysis were normal. The white blood cell count was within normal limits (17,400 cells/mm3). It was not until 6 hours after the onset of inconsolable crying (2.5 hours after presentation to the emergency department) that the patient's temperature rose to 38.5 degrees C (101.3 degrees F). Clinical signs of mastitis did not become appreciable until the 2nd hospital day. We review the literature on infantile mastitis and acute, unexplained, excessive crying. The importance of a thorough, conservative approach to the infant with acute, unexplained, excessive crying is discussed.