Recurrent primary headache is the most frequent manifestation of pain in childhood (Eggers, 1984) and is present in up to 8% of 6-year-old children (Haffner et al., 1998; Sillanpää and Anttila, 1996). After the first year of school, headache prevalence doubles; therefore, school is an important influencing factor. Prevalence of recurrent primary headache during childhood has increased over the last few decades to 10.6% (Abu-Arafeh and Russell, 1994). Childhood headache has a high risk of chronification and persists into adulthood at about a 60% rate of recurrence (Bille, 1981). And in adults, chronic headache, especially migraine, causes high socioeconomic health care costs, mainly due to high indirect costs (e.g., absenteeism, reduced work efficiency) (Fishman and Black, 1999).
Characteristics of headache in children are less typical and more variable than in adults, and small children have more difficulties perceiving and describing headache characteristics in detail. Abdominal symptoms, such as cyclical vomiting or abdominal "migraine," are common precursors to migraines and occur especially in preschool children.Diagnosis
Most often, primary headache can be classified as migraine or tension-type headache. Diagnosis is made according to the (recently modified) criteria of the International Headache Society (IHS) (2004) and includes duration, quality and intensity of the headache, and vegetative or neurological symptoms (Table). Parents often underestimate intensity and frequency of their child's headaches; therefore, diagnosis should be based on four to eight weeks of prospective monitoring using a headache diary, to record headache characteristics, drug intake, probable trigger factors and impact on daily life in a standardized way. Self-monitoring and documentation of symptoms may even lead to a reduction of pain.
A thorough history, as well as a physical and neurological examination, is essential for ruling out underlying diseases or situations that can cause secondary headaches, such as head trauma, infection, organic lesion or sinus disorders (IHS, 2004). Psychotropic drugs can be another source of headaches. Laboratory tests, including electroencephalogram and imaging studies, should not be undertaken routinely, but they should be performed when warranted by any specific clinical evidence. Headache in children younger than 3 and occipital headache in children always call for diagnostic caution.Migraine Headache
Migraines manifest in attacks lasting four to 72 hours in adults and one to 72 hours in children (IHS, 2004). Typical characteristics are unilateral location (in young children commonly bilateral), pulsating quality, moderate or severe intensity, aggravation by physical activity, and association with nausea and/or photo- and phonophobia (which may be inferred from particular behaviors in young children). Migraine episodes are frequently triggered by several factors such as emotional stress (school pressure, excitement), lack of or excess sleep, sensorial stimulation (loud noise, bright light), or sympathetic stimulation (physical activity). Up to 30% of patients with migraines occasionally experience auras--reversible focal neurological symptoms--(typically visual and/or sensory and/or speech symptoms--that develop gradually over minutes and last for less than one hour. Frequency of migraine aura seems to be nearly as high in children as in adults, but the less typical symptoms are usually only reported on request rather than spontaneously.Tension-Type Headache
Tension-type headaches manifest in episodes lasting minutes to days. The pain is typically bilateral, pressing or tightening in quality, and of mild or moderate intensity. Vegetative symptoms are negligible, and the headache does not worsen with routine physical activity. Chronic (>180 days/year) childhood headache (tension-type or migraine) is nearly always associated with psychiatric comorbidity (Guidetti et al., 1998) and may represent a correlate of a psychiatric problem.Prognosis
There are only a few investigations of long-term outcomes of headache in children. Chronification rates of 60% for migraine and 45% for tension-type headache have been reported (Guidetti and Galli, 1998). Before puberty, the gender ratio is balanced, but young boys experience a two- to threefold greater rate of spontaneous remission of headaches. Chronification risk of childhood headaches increases enormously when psychiatric comorbidity is present. A follow-up study by Guidetti et al. (1998) reported headache in 85% of children with psychiatric comorbidity, but only in 60% of patients without psychopathology. None of the children in the study who experienced spontaneous remission of headache had clinically relevant psychiatric problems. On the other hand, children with frequent headache recurrence had an increased risk of multiple physical symptoms and psychiatric disorders in adulthood.