People affected by<unk>  often describe their headache attacks as excruciating pain. The attacks are severe enough to disrupt daily activities, but hospitalization is not necessary for most affected individuals. Frequency and duration The average number of attacks per day is around 60, ranging from 3 to 200 times. The attacks can be divided into three groups: single stabs, groups of stabs, and attacks with saw-tooth pattern, from the shortest to the longest duration respectively. The attacks usually last from five seconds to 240 seconds. Typically, longer attacks are more painful due to psychological effects, and patients often feel agitated before and during the attack. They occur mostly in the orbital, supraorbital, or temporal region, but can also occur in the retro-orbital (behind the orbit of the eye) region, side, top, and back of head, second and third trigeminal divisions, teeth, neck, and ear. Cranial autonomic symptoms associated with headache attacks<unk>  often accompanies cranial autonomic symptoms, including lacrimation (tear flow), ipsilateral ptosis (drooping of the eyelid which is on the same side as the attacks), eyelid edema (swelling due to fluid accumulation), nasal blockage, and conjunctival injection (redness of eye). Depending on which division of the trigeminal nerve innervates the area affected, autonomic symptoms may be less obvious. Short-lasting unilateral neuralgiform headache attacks with cranial autonomic features (SUNA) is a subset of<unk>  and may be diagnosed when fewer autonomic symptoms are observed during attacks. The majority of<unk>  attacks occur chronically; however, some occur episodically. In chronic<unk> , attacks can occur regularly or irregularly without a distinct refractory period, whereas in episodic<unk> , attacks occur only for a certain period of time and then cease for another period. Episodes of attacks last from a few days to a few months, and up to 22 attack episodes in one year have been observed.<unk>  can go into remission even after a chronic period, and relapse either spontaneously or due to some stimulus. Triggers of headache attacks Most of the time<unk>  occurs spontaneously; however, attacks can be triggered by simple daily stimuli such as touching the face or scalp, washing, chewing, eating, talking, coughing, blowing nose, or showering. They also can be triggered by light (including sunlight and fluorescent lights) and injuries. Stimuli capable of triggering a cluster headache, including alcohol, smoke, strong smells and a warm environment, can also trigger<unk>  in a few patients. In some cases, patients with episodic<unk>  only exhibit symptoms biannually, in spring and fall. This periodicity suggests that the hypothalamus, which is responsive to day length and photoperiod for regulating circadian and seasonal rhythms, has a role in its triggering.
SUNCT syndrome
MASA syndrome
SAHA syndrome
Hopkins syndrome
TAN syndrome
EAST syndrome
Crome syndrome
Bogart–Bacall syndrome