At least five attacks are required for a definite diagnosis. If a patient has had fewer than five, attacks should be coded as affected by a probable migraine without aura (1.5.1).

In children and adolescents (aged under 18 years), attacks may last 2–72 h (the evidence for untreated durations of less than 2 h in children has not been substantiated, and attacks are more often bilateral than in adults). Location is usually frontotemporal. Unilateral pain generally emerges in late adolescence or early adult life. Occipital headache in children is quite rare and calls for diagnostic caution.

A menstrual relationship is often evident for migraine without aura. ICHD-3 beta offers criteria (in the appendix) for A1.1.1 pure menstrual migraine and A1.1.2 menstrually related migraine.

Based on retrospective analysis, prevalence of menstrual migraine ranges from 26 to 60 % in headache clinic patients. Menstrual migraine occurs at the time of the greatest fluctuation in oestrogen levels, particularly during or after the simultaneous fall of oestrogens and progesterone. Pure menstrual migraine is defined if attacks occur −1 to +4 days of menses.

Neck pain is a quite common symptom occurring during a migraine attack. This is possible, due to the overlap and the convergence of pain processing from the trigeminal, occipital and cervical regions in the so-called trigeminocervical complex. For this reason, neck pain may trigger or worsen migraine pain, and migraine may be associated to neck pain. An erroneous diagnosis of “cervicogenic headache” is sometimes the result of symptoms misinterpretation.

Aura may begin after the pain phase has commenced or continue into the headache phase. Visual aura is the most common type of aura, occurring in over 90 % of patients with 1.2 migraine with aura, at least in some attacks. Visual auras vary in its complexity. Positive phenomena, negative phenomena or both may occur. Positive phenomena often occur first and are then followed by negative phenomena. Elementary visual disturbances include phosphenes (simple flashing), scotomata (starting centrally and migrating—“marching”—peripherally or sometimes vice versa), shimmering or undulation in the visual field. More complex auras included fortification spectrum (an arc of scintillating lights often “C” shaped, migrating across the visual field with a scintillating edge of sometimes zigzag, flashing or occasionally coloured—from grey to purple, often only excessively bright white—phenomena). In other cases, scotomata without positive phenomena may occur. Visual distortions and hallucinations occur more commonly in children, characterized by a very complex disorder of visual perception that may include micropsia, macropsia, mosaic vision and metamorphopsia. When aura presents as distorted images, bizarre visual illusions or spatial distortions, Alice-in-Wonderland syndrome may be considered.

Paraesthesias are the second most common aura phenomenon. It infrequently occurs in isolation and usually follows a visual aura. They typically start in the form of pins and needles in the hand, migrating up the arm and then continuing to involve the face, lips and tongue.

Less frequent are speech disturbances, usually aphasic (17–20 % of patients).

Aura symptoms of these different types usually follow one another in succession, beginning with visual, then sensory and then speech abnormalities (but the reverse and other orders have been described). The typical duration of migraine aura (non-hemiplegic) may be longer than 1 h in 6–10 % of patients with visual symptoms, 14–27 % of patients with sensory disturbances and 17–60 % with aphasic aura. Considering these data, the term “prolonged aura” should be re-established in ICHD-3 as a clinically useful definition.

Premonitory symptoms may begin hours or days before the other symptoms of a migraine (with or without aura) attack in 60 % of cases. They include change in mood or behaviour, fatigue and difficulty in concentrating. In some patients, mental state may become euphoric, talkative and hyperactive. Premonitory symptoms are quite variable among individuals but rather consistent within an individual. Episodic bouts of food craving are quite common and sometimes reported as a part of “migraine complex” premonitory symptoms. They are not to be confused with the aura phase.

When aura occurs for the first time after age 40, when symptoms are exclusively negative (e.g. hemianopia) or when aura is prolonged or very short, other causes, particularly transient ischemic attacks, should be ruled out. “Late life migrainous accompaniments” were described as transient (15–25 min) neurological phenomena not associated to migraine (visual “build-up” scintillating scotoma, dizziness, paraesthesias in “march”), occurring for the first time after age of 45 years in patients with a previous history of recurrent headache. For a correct diagnosis, cerebral thrombosis and transitory ischaemic attacks have to be ruled out (Table 1.5).

Migraine attacks may start at any age, although the incidence peak is in adolescence. The 1-year prevalence of definite migraine in adults is 11 % overall (15–18 % among women, 6 % among men) [6]. The prevalence estimates are quite comparable across the world.

Several recent studies have provides estimates of migraine with aura. The weighted average 12-month prevalence rate is 4.4 %. The aggregate weighted rate of definite migraine in children is 10.1 % (1.6 % migraine with aura). In the past 20 years, the prevalence of migraine has been stable, whereas episodic migraine and chronic migraine remain undertreated [7]. Women are particularly prone to migraine, with different susceptibilities throughout their life influenced by hormonal (oestrogen) fluctuation. Migraine may occur in the first or second trimesters of pregnancy, but they improve as pregnancy progresses parallel with increasing oestrogen levels. About 40 % of women will report their first migraine attack during pregnancy (particularly with aura) or shortly after delivery. Migraines may worsen after delivery as oestrogen levels dramatically drop. The burden of disease may increase in severity and frequency at the onset of perimenopause, but migraine generally lessens after menopause being rare in elderly women [8]. Among all putative triggers (other than sex hormones), stress is the most quoted and food is the second reported cause. The common lists of food triggers include tyramine-containing foods (bananas, avocados, smoked fish, aged cheese as Camembert, red wine), nitrate-containing foods (salami, hot dogs and bacon), monosodium glutamate (soy beans and sauce, pickled and marinated foods) and histamine (especially in seafoods).

However, significative scientific evidence (based on controlled trials) linking consistency of diet with clear improvement in migraine is extremely poor and limited.

Patients who are affected by 1.1 migraine without aura or 1.2 migraine with aura may have episodic syndromes associated with migraine. Although historically noted to occur in childhood (previously used terms were “childhood periodic syndromes”), they may also be diagnosed in adults. Other conditions that may also be associated in these patients include episodes of periodic sleep disturbances (sleep talking, sleepwalking, bruxism and pavor nocturnus) and motion sickness.

Episodic syndromes that may be associated with migraine are classified as (a) 1.6.1 recurrent gastrointestinal disturbance, (b) 1.6.1.1 cycling vomiting syndrome, (c) 1.6.1.2 abdominal migraine, (d) 1.6.2 benign paroxysmal vertigo and (e) 1.6.3 benign paroxysmal torticollis.

Recurrent gastrointestinal disturbance may be associated with migraine. It is characterized by episodic attacks of abdominal pain and/or discomfort, nausea and/or vomiting, occurring infrequently, chronically or at predictable intervals, with normal gastrointestinal examination.

Abdominal migraine is diagnosed mainly in children and is characterized by recurrent attacks of abdominal pain lasting 2–72 h. Pain is described of moderate or severe intensity (interfering with normal daily activities) with midline or periumbilical location and dull or sore quality. During attacks, at least two symptoms have to be present (anorexia, nausea, vomiting, pallor). Most children with abdominal migraine will develop a definite migraine (with or without aura) later in life. Many of the migraine treatments may also be effective for abdominal migraine.

Older classifications considered “ophthalmoplegic migraine” as a particular form of migraine. It is characterized by repeated attacks of paresis of one or more ocular cranial nerves (in particular oculomotor 3rd nerve) in association with ipsilateral headache. ICHD-3 beta described this head pain as 13.9 recurrent painful ophthalmoplegic neuropathy. Diagnostic criteria are fulfilled if in two attacks the patient presents with unilateral headache accompanied by ipsilateral paresis of one, two or all three ocular motor nerves and orbital, posterior fossa or parasellar lesion has been excluded by neuroradiological examinations. The old term “ophthalmoplegic migraine” was refused because the syndrome is a recurrent painful neuropathy, with headache developing up to 2 weeks prior to ocular motor paresis. With MRI, contrast enhancement (with gadolinium) or nerve thickening can be demonstrated, and steroid therapy is useful in most of patients.

Migraine is reported to be comorbid to many pathologies, in particular other neurological disturbances (epilepsy and Gilles de la Tourette syndrome), vascular pathologies (ischaemic stroke, subclinical brain white matter abnormalities), psychiatric disturbances (depression, anxiety, panic disorder and bipolar disorder), asthma and allergies.

The natural history of migraine is not been well characterized, and the same is for prognosis. Some classical patterns are suggested, such as clinical remissions (attack-free for long periods of time), persistence (attacks continuation over years with or without changes in severity, symptoms profile and frequency) and progression (increase of both frequency and related disability in quality of life). Clinical progression leads to chronicization (2 % of migraineurs, women more frequently than men), including physiological (central sensitization) and sometimes anatomical progression (deep white matter lesions as detected by magnetic resonance imaging). Neuroimaging studies on migraine patients have suggested the prevalence of both structural and functional brain changes between migraine attacks. Severity of white matter lesions correlated with disease duration, type of migraine (with or without aura) and frequency of attacks. They are interpreted as an indirect marker of focal cerebral hypoperfusion induced by migraine attacks, particularly if repeated (i.e. in high-frequency migraine, particularly with aura). Small white matter lesions are not infrequent in both children and adolescents suffering from migraine (without prevalence in patients affected by migraine with aura compared with patients affected by migraine without aura). No relationship between brain lesions and patent foramen ovale was detected in children and adolescents with migraine. Repeated and prolonged oligaemia occurring during migraine attacks may affect the more vulnerable small deep penetrating arteries, while local critical hypoperfusion may lead to minor brain injury (ischaemic demyelination and gliosis) revealed as white matter lesions. Other putative mechanisms include endothelial dysfunction (activation and impaired vascular reactivity): if accompanied with platelet aggregation, this process of endothelial changes mediated by radical oxygen species (ROS) may lead to microvascular brain damage [9]. The longevity of clinical history (duration of migraine disease) is associated with increase iron deposition in periaqueductal grey, putamen and globus pallidus. Moreover, reduction in density of both white and grey matter as evaluated with voxel-based morphometry in migraineurs is dependent on both duration of disease and frequency of attacks. Results from longitudinal studies on migraine and cognitive decline consistently show that those who experience any type of migraine (with or without aura) are not at increased risk of cognitive decline. This is confirmed among people affected by migraine and high structural brain lesion load, suggesting that while migraine may be associated with structural brain lesions, the correlation with cognitive decline is lacking [10]. Although these data should provide reassuring evidence, further information are needed (attack frequency and duration) to confirm the conclusions. Risk factors for migraine progression have been supposed such as obesity, snoring and excessive use of caffeine [11] (Table 1.6).