Physician has inadequate level of comfort in diagnosing or treating patient's headache.

Patient requests a referral.

Initial diagnosis is in question.

Patient does not respond to treatment.

Patient's condition or disability continues or worsens.

Physician is unable to classify patient's headache according to diagnostic criteria for primary or secondary headache disorders.

Habituation or rebound headaches limit outpatient management.

Patient has intractable or daily headaches.