Trigeminal Autonomic Cephalalgias (TACs) – SUNCT/SUNA

Short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) and short-lasting unilateral neuralgiform headache attacks with cranial autonomic symptoms (SUNA) are rare headache syndromes which make up the trigeminal autonomic cephalalgias (TACs), along with cluster headache and paroxysmal hemicrania. All of the TACs are characterized by attacks of severe or excruciating unilateral facial and head pain associated with ipsilateral cranial autonomic symptoms such as conjunctival injection, lacrimation, nasal blockage, rhinorrhoea, ptosis, and eyelid edema. SUNCT and SUNA are the rarest of the TACs, and are characterized by the shortest duration of attacks. In SUNCT, by definition, conjunctival injection and lacrimation are present. SUNCT forms the majority subset of SUNA, where there are any or all of the cranial autonomic symptoms. In SUNA, there may be conjunctival injection, lacrimation, neither of these, but not both.