The attacks in [[SUNCT syndrome]] are strictly unilateral, generally with the [[pain]] persistently confined to the [[ocular]]/periocular area. Most attacks are moderate to severe in intensity and [[burning]], [[stabbing]] or electrical in character. The mean duration of paroxysms is 1 minute, with a usual range of 10 to 120 seconds (total range 5 to 250 seconds). Prominent, ipsilateral [[conjunctival injection]] and lacrimation regularly accompany the attacks. Nasal stuffiness/rhinorrhoea is frequently noted. In addition, there is a subclinical forehead sweating. During attacks, there is increased [[intraocular pressure]] on the symptomatic side and swelling of the [[eyelid]]s. No changes in pupil diameter have been observed. Attacks can be triggered mostly from trigeminally innervated areas, but also from the extratrigeminal territory. There are also spontaneous attacks. An irregular temporal pattern is a rule, with symptomatic periods alternating with remissions in an unpredictable fashion. During active periods, the frequency of attacks may vary from <1 attack/day to >30 attacks/hour. The attacks predominate during the daytime, nocturnal attacks being seldom reported.