Trigeminal Autonomic Cephalalgias

Trigeminal autonomic cephalalgias (TACs) are a family of severe one-sided headache disorders sharing autonomic features on the painful side — red watery eye, blocked or running nostril, drooping eyelid. The family includes cluster headache, paroxysmal hemicrania, hemicrania continua and SUNCT/SUNA. Diagnosis hinges on attack length, frequency and treatment response, and every first presentation is investigated with MRI to exclude secondary causes.