Methods
We conducted a retrospective chart review of 4 370 consecutive pediatric patients affected by primary headache and referred to the Headache Centre of Bambino Gesù Children's Hospital from July 2002 to December 2010. Among these patients, we selected those who met the diagnostic International Classification of Headache Disorders–II criteria for cluster headache.1
All selected patients underwent a general and neurological examination, including a detailed evaluation of cranial nerves and face, neck, and cephalic structures. Blood examinations were performed and thyroid hormone levels were investigated.
Parents of all patients were called retrospectively to investigate about possible exposure to secondhand smoke at home and alcohol consumption.