Discussion The trigeminal autonomic cephalgias (TACs) are a group of primary headache disorders characterized by unilateral pain in the trigeminal nerve distribution, associated with ipsilateral cranial autonomic features (1, 2). This group of headache disorders includes cluster headache, paroxysmal hemicrania and short-lasting, unilateral, neuralgiform headache attacks with conjunctival injection and tearing (SUNCT syndrome)(1, 2)(Table 1). Despite their similarities, these disorders differ in their clinical manifestations and response