title: Diagnosing headache.
abstract: BACKGROUND
  A systematic approach to the diagnosis of primary and secondary headache disorders requires the measurement of the frequency and the duration of headache.
  
  
  OBJECTIVE
  This article presents thumbnail sketches of the most important headache subtypes and discusses some of the new revisions and headache types included in the International Classification of Headache Disorders (ICHD 2).
  
  
  CONCLUSIONS
  The clinical features that distinguish secondary headaches requiring urgent investigation (red flags) from those that can be more safely monitored (blue flags) are discussed.
authors.affiliation: Epworth and Royal Melbourne Hospitals, Victoria, Australia.
authors.forename: Jacques
authors.initials: J
authors.lastname: Joubert
mesh_terms: D003027:Cluster Headache / Q000175:diagnosis; D003937:Diagnosis, Differential; D005194:Family Practice / Q000379:methods; D005260:Female; D006261:Headache / Q000145:classification / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008881:Migraine Disorders / Q000175:diagnosis; D012307:Risk Factors; D018781:Tension-Type Headache / Q000175:diagnosis