Trigeminal autonomic cephalalgias (TACs)
TACs are a group of headache
syndromes incorporating short lasting
severe unilateral headache attacks,
accompanied by cranial autonomic
symptoms. TACs is included in the
International Headache Society
classification of headaches28 and includes
cluster headache, paroxysmal hemicrania
and short-lasting unilateral neuralgiform
headache attacks with conjunctival
injection and tearing (SUNCT), all of
which display trigeminal distribution
pain and ipsilateral cranial autonomic
features. The primary site of pain is in the
distribution of the first division of the
trigeminal nerve and autonomic features
present. They are rare, not expected to be
diagnosed in primary care and the main
features are highlighted in Table 2.