Abstract
Background: Chronic daily headaches (CDH) occur in >4% of the adult population. The criteria for CDH, however, are controversial. In children, the characterization of frequent headaches and CDH is limited.
Methods: A Headache Center to characterize headaches in children (3 to 18 years old) was established. Over 34 months, 577 children have been evaluated. With use of a definition of ≥15 headaches per month, 200 (34.6%) children had CDH.
Results: The average age at the first headache in these children was 9.3 ± 3.6 years, whereas the average age at presentation to the Headache Center was 12.5 ± 3.1 years. Sixty-eight percent were girls, 88% were Caucasian, and 11% were African American. Ninety-two percent clinically had migraine headaches, whereas 60.5% met the International Headache Society migraine criteria. The pain was pulsatile in 79%, 63.5% had nausea with or without vomiting, and 59.5% had photophobia and phonophobia. Three subcategories emerged, with 37% having frequent headaches but not daily, 43.5% having episodic daily headaches, and 19.5% having a continuous headache.
Conclusion: The features of CDH in children most closely match those of migraine. A clear division of these children using frequency identifies three groups: frequent headaches (15 to 29), daily intermittent, and daily continuous. The daily continuous group is the most unique; however, the nature of these headaches continues to remain migrainous.
In children, migraine prevalence ranges from 2.7 to 10.6%1-3⇓⇓ and may be as high as 28% between ages 15 and 19.4 The prevalence of chronic daily headaches (CDH) is as high as 4% in adults5 but much lower in children (0.026 to 0.09%3).
CDH are not included in the International Headache Society (IHS) criteria. The 1994 criteria for CDH included four major categories: transformed migraines (TM), chronic tension-type headache (CTTH), new daily persistent headache (NDPH), and hemicrania continua (HC).7 These criteria were refined,8 and 150 consecutive adults with CDH were classified with TM (78.0%), CTTH (15.3%), or other CDH-HC or NDPH (6.7%). In 37 children with CDH, 40% had “co-morbid” headaches (intermittent migraines with underlying tension headaches), 35% had NDPH, and 15% had TM.9 Characterization of more children with CDH is clearly needed to better understand this headache presentation.
One contributor to frequent headaches is analgesic overuse.10 In a retrospective review of 98 children, 46 had daily or near daily headaches, with 30 taking daily analgesics.11 Twenty-four children discontinued their daily analgesics with improvement in their headaches.
We studied CDH in children (3 to 18 years old) in a tertiary pediatric center. With use of a criterion of ≥15 headaches per month, the CDH of 200 children are examined and possible criteria discussed. These data should greatly aid in the current management of CDH in children and lead to the development of more effective interventions.
Materials and methods.
Patient population.
We prospectively studied all children referred to the Headache Center at the Cincinnati Children’s Hospital Medical Center. A detailed questionnaire about the headache’s features and general health characteristics was obtained. The questionnaire was reviewed in detail at the initial visit to ensure accuracy and assist in medical decision making. We performed a thorough history and general physical and neurologic examination and used the IHS criteria for the diagnosis.
Screening criteria for CDH in children.
In the proposed CDH criteria,7,8⇓ a frequency of >15 headache days per month and a duration of >4 hours were used. These CDH were categorized into TM, CTTH, NDPH, and HC. Owing to questions about the validity of the IHS criteria for CDH and for childhood headaches, we defined CDH as a minimum of 15 headache days per month. Headache duration was not used as a screening criterion, given that children may experience shorter headaches.12,13⇓
Headache characteristics.
Headache frequency, duration, severity, pain quality, location, associated symptoms, and impact of the headache on daily activities were examined. We compared the entire Headache Center population, children with <15 headache days per month, and those with ≥15 headache days per month (CDH). The CDH group was divided into those with frequent but not daily headaches (i.e., 15 to 29 headache days; frequent headaches), those with daily headaches but not continuous headaches (daily intermittent), and those with continuous headaches (daily continuous). The patient’s diagnosis included both the clinical impression as well as the diagnosis by IHS criteria. The computer database was screened with queries designed to match the IHS criteria for migraine without aura, migraine with aura, and tension-type headaches. Statistical analyses were performed with means and standard deviations applied to z and p scores using a normalized distribution. A statistical standard of p < 0.01 was used throughout the study to minimize the influence of potential interdependent variables.
Results.
Between July 1997 and May 2000, 577 children were evaluated. Two hundred (34.6%) children had ≥15 headache days per month (CDH). A total of 126 children (21.8% of total, 63.0% of CDH) had 30 headache days per month, with 39 (6.7% of total, 19.5% of CDH) reporting continuous headaches.
Demographics.
For the children with CDH, the age at the first headache and the age at presentation were significantly older than those of the entire population ( table 1). The ages of the children with CDH ranged from 3 to 18 years. Within the CDH group, the frequent headache group was the youngest, followed by the daily intermittent and daily continuous groups. There was approximately a 3-year delay between the age at the first headache and the age at presentation (p < 0.0001 for all groups). The greatest difference was in the daily continuous group (3.6 years), and the smallest difference was for children without CDH (2.9 years).
Demographics
Nearly all of the children with CDH (94.5%) had a normal neurologic examination. Forty-five percent of all the children had a mild degree of dehydration based on tacky mucous membranes, decreased capillary refill, and mottled skin. Mild dehydration occurred in 59.5% of the children with CDH compared with 38.6% of children without CDH.
The overall ratio of girls to boys was slightly more than 1, whereas more than twice as many girls had CDH compared with boys. The racial distribution approximated the general population in the Cincinnati metropolitan area based on 1990 Census Bureau information for all of the groups.
Headache characteristics.
Frequency.
All of the children with CDH had at least five headaches ( table 2). The CDH group’s frequency was significantly greater than that of the entire sample or those without CDH. These differences were expected, secondary to the definitions used to establish the groups. The children were unable to determine when their frequency first exceeded 15 headaches per month, although most felt that their headaches had become progressively more frequent.
Headache characteristics
Duration.
The mean duration of the “average” headache for the children with CDH was slightly longer than that of the entire group (see table 2). For the three subgroups of CDH, this duration was greatest for the daily continuous group. This duration was significantly longer for the daily continuous and daily intermittent groups compared with the total group and those without CDH.
The IHS criteria for migraine allow children under 15 years old to have shorter headaches. When duration was screened by age, 68.0% of all children <15 years old had an “average” duration of >2 hours and 56.5% who were 15 years old or older had an “average” duration of >4 hours. Thus, 65.7% children met the IHS duration criteria for migraines. With use of this analysis for CDH, the duration criterion was met in 65.0% of all CDH, 70.3% of frequent headache, 54.0% of daily intermittent, and 79.5% of daily continuous groups.
Pain quality.
Most of the children’s headaches had a throbbing quality, whereas one-third had a pressure quality and one-fifth had a squeezing quality (see table 2). Similarly, the headaches of children with CDH often had a throbbing quality. This was also the most common quality within the individual subgroups, without any significant difference. A pressure quality was significantly more common in the CDH group versus the total population and those without CDH, and the headache was more frequently described as constant for the CDH group.
Location.
The headaches were most often bilateral for all the groups, without any significant difference (see table 2). For the entire group, the children with CDH, and the subgroup of CDH, the most common single location was frontal, although it was lowest for the daily continuous group. A temporal location (bilateral or unilateral) was also frequently observed for the entire group (41.9%), the children with CDH (52.5%), and the subgroups of CDH, with a higher fraction in the frequent headache (63.5%) and daily continuous (61.5%) groups and lower fraction in the daily intermittent group (49.4%).
Severity.
Moderate to severe pain occurred in nearly all of the children, although a trend of decreasing severity with increasing headache frequency was seen (see table 2). None of the differences in severity was significant.
Associated symptoms.
The most common associated symptoms were nausea, vomiting, photophobia, and phonophobia ( table 3). For the children with CDH, these remained the most common associated symptoms, but both nausea and vomiting were significantly less frequent in the CDH groups. Photophobia was lower in the daily intermittent and daily continuous groups when compared with the frequent headache group. Overall, 75.0% of the children with CDH met the IHS criteria for associated symptoms. A similar percentage met the IHS criteria in the frequent headache (77.0%) and daily intermittent (75.9%) groups, but less in the daily continuous group (69.2%).
Associated symptoms
Analgesic rebound.
Frequent analgesic use occurred in 38.5% of the children with CDH, with 61.0% using analgesics daily and 71.4% using analgesics five or more times per week. For the three CDH subgroups, 37.8, 33.4, and 51.3% had analgesic rebound, with 50.0, 65.5, and 70.0% taking analgesics daily.
Functional impact.
The headaches limited nearly all of the children’s activity and worsened with activity ( table 4). There was no significant difference between the groups. The functional ability in school during a headache was significantly worse for the total group compared with the CDH group. For children without CDH, the functional ability was even lower, whereas for the CDH subgroups, the functional ability was significantly better than that of the total group and the group without CDH. At home, the functional ability was even lower for all but the daily continuous group. This difference was significant only for the entire group and for those children without CDH. There was no significant difference in school absences between the groups, although the daily continuous group did have the most absences.
Impact on quality of life
Diagnosis.
The most common clinical diagnosis was migraine or migraine with aura, with the IHS criteria often met for these (table 5). For CDH children, a clinical diagnosis of migraines persisted, whereas a lower percentage met the IHS criteria. For the subgroups, the percentages were similar, except for the daily continuous group (as a continuous headache could not be classified as episodic). No significant differences in the clinical diagnosis of migraine were observed among any of the groups. The IHS diagnosis of migraine was significantly less for CDH compared with either the total group or the children without CDH. With computer screening, the diagnoses of migraine in the total CDH group and the daily intermittent group were significantly lower than for children without CDH, whereas the diagnosis of migraine was lower for only the daily intermittent group when compared with the total population. Tension-type headaches occurred more frequently in the CDH children by all three methods of analysis. For the subgroups, this was true only for the daily intermittent and daily continuous subgroups.
Diagnosis
Discussion.
Children with frequent headaches commonly present to a pediatric headache center. According to a criterion of ≥15 headache days per month, most of the headaches of children with CDH were clinically consistent with a diagnosis of migraines, whereas the IHS criteria were met in over half. Even in children with continuous headaches, migraine characteristics persisted. This supports the hypothesis that CDH in children represent migraines—possibly transformed migraines. The children were unable to clearly describe a transformation. They did give the impression that their headaches started as episodic.
The children with CDH had an older mean age for both the first headache as well as the clinical presentation. The girl/boy ratio was also much higher for the CDH groups. Combining these observations suggests that children with CDH are more likely to be older girls. This is most likely a reflection of the increasing headache prevalence in girls as children age.
Headache frequency was the defining characteristic for this study. For CDH, we observed a clear division into frequent headaches (but not daily) and daily headaches. The frequent headache group represents the upper spectrum of children with episodic headaches and may be a progression from episodic to CDH. The daily headaches were clearly noted by the patients and were well defined as either intermittent or continuous.
The IHS criteria serve as the basis for the diagnosis of headaches. Their usefulness in children has been criticized,12-15⇓⇓⇓ and a characterization of CDH in children has not been established. The headache features described herein reveal that migraine characteristics predominate in children with CDH. This suggests that childhood CDH represents transformed or frequent migraines.
Most of the children described a throbbing headache. As the headache frequency increased, the children had more difficulty describing the pain. A report of constant pressure increased, though a throbbing quality predominated. This resulted in an increase of tension-type headache in the daily continuous group. Although this may represent a change in diagnosis, this may be an adaptation to the pain, with pain quality being less important in continuous headaches.
The duration of the average headaches differed in the daily intermittent and daily continuous groups from that in the remainder of the population. The daily intermittent group had shorter headaches, whereas the daily continuous group had a much longer headache. It is unclear why this shortening of headache duration occurs in the daily intermittent group, but it may represent a coping mechanism or an alteration in pain sensitivity.
The unilateral requirement of the IHS criteria has been criticized, with a higher likelihood of bilateral pain in children. In all of the children studied, a bilateral location uniformly persisted, with no differentiation between the groups. This further supports the hypothesis that childhood CDH are an extension of childhood migraines.
The children with CDH have a high frequency of associated symptoms commonly seen in migraines. Gastrointestinal symptoms vary with headache frequency. Vomiting diminishes with increased frequency, with more nausea in the group without CDH and less in the daily continuous group. Anorexia, however, is fairly uniform, lower only in the daily intermittent group. This may represent an adaptation to the gastrointestinal symptoms rather than a difference in pathophysiology. Photophobia and phonophobia show less variation. The daily continuous group has the lowest frequency of these symptoms, which also could be adaptation. In adults, light sensitivity has been shown to be wavelength specific for different headaches.16 The decrease in photophobia could reflect a change in wavelength sensitivity as a function of headache frequency. This may represent a useful tool to track the progress of patients with CDH. Lightheadedness also worsened with increased frequency. This may be due to the vascular component of migraines and the children being mildly dehydrated with a positive response to fluid replacement.
When the headache features are combined, a migraine diagnosis predominates in all but the daily continuous group (see table 5, IHS diagnosis). This is an aberration of the IHS criterion that migraines are episodic (i.e., constant headaches cannot be classified as migraines). When clinical characterization or computer-based screening is used (with the “duration” of 24 hours), migraines again are the most common diagnosis. For children, the clinical diagnosis of migraine increases the specificity compared with the IHS diagnosis.14 With use of the IHS criteria, either subjectively or with a computer database, the diagnosis was similar for all groups. This further supports the hypothesis that childhood CDH are variations of migraines. The diagnosis of tension-type headache increased with more frequent headaches. Whether this is a true characteristic of CDH or merely represents a decrease in the migraine-specific characteristics is unclear. Following the CDH patients as they respond to therapy should elucidate if the CDH become more migrainous or tension type.
Many of these children had analgesic rebound contributing to their CDH. This was relatively unique to the children with CDH, with only rare instances in children without CDH. This is consistent with the theory of analgesic-induced CDH.10 This daily analgesic use occurred even in the frequent headache group, although the overuse of analgesics remained highest in the daily continuous group. In this respect, the role of analgesic rebound in children seems similar to that in adults.
A comprehensive assessment of quality of life was not conducted with these children. However, given the experience in adults, the CDH in children are likely to have a significant impact on their quality of life. Early recognition and treatment should minimize this impact. Aspects that reflect the quality of life in this study include both school absences and functional ability during a headache. Many school days are missed because of headaches. This did not significantly differ between the groups, although more days were missed in the CDH children, especially the daily continuous group. The children with CDH seem to be learning to cope with the recurrent pain, at least to the point of attending school. In comparing functional abilities, the children with CDH reported functioning better than those with less frequent headaches. At home, however, this was seen only for the frequent headache group. This would further suggest that the children with CDH are coping while at school with a decompensation at home. Nevertheless, these children were consistently functioning below 50% of their abilities on days when they had a headache. Combining the frequency of headaches with the diminished functional ability during a headache amplifies the significant impairment in children with CDH.
- Received June 16, 2000.
- Accepted December 5, 2000.
References
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