The classification of chronic daily headache in adolescents--a comparison between the second edition of the international classification of headache disorders and alternative diagnostic criteria

OBJECTIVES: To compare the second edition of the International Classification of Headache Disorders (ICHD-2) and the Silberstein-Lipton (S-L) criteria in the classification of adolescents with chronic daily headache (CDH). METHODS: We reviewed the clinical records and the headache diaries of 170 adolescents (13 to 17 years) seen between 1998 and 2003 at a headache center. Relevant information was transferred to a standardized form that included operational criteria for the ICHD-2. CDH subtypes were classified according the criteria proposed by S-L into transformed migraine (TM) with (TM+) and without medication overuse (TM-), chronic tension-type headache (CTTH), new daily persistent headache (NDPH), and hemicrania continua (HC). RESULTS: From the 69 patients with TM- according the S-L criteria, most (71%) could be classified as chronic migraine (CM), while a minority of patients required a combination of diagnosis, mainly migraine and CTTH (14.4%). Of the patients with TM+, just 39.6% met the criteria for probable CM (PCM) with probable medication overuse (PMO). If instead of 15 migraine days per month, we considered 15 or more days of migraine or probable migraine, 84% of the subjects with TM- and 68.7% of those with TM+ could be classified. Of the 27 subjects classified as NDPH without medication overuse according to the S-L system, the majority (51.2%) were also classified as NDPH according the ICHD-2. Interestingly, three (11.1% of the subjects with NDPH without medication overuse) were classified as CM in the ICHD-2 because these patients had an abrupt onset of 15 or more days of migraine per month. All patients with NDPH with medication overuse according to the S-L criteria required a combination of diagnoses in the ICHD-2. All subjects with CTTH received a single diagnosis in both classification systems. CONCLUSIONS: (i) Among adolescents with TM, the majority (58.1%) could be classified as CM, according to the ICHD-2. These results were driven by TM without medication overuse. (ii) If the ICHD-2 criteria for CM are revised to require 15 days of migraine or probable migraine, the proportion of patients with TM- who meet the criteria for CM increases from 71% to 84%; for TM+, the proportion with probable chronic migraine and PMO increases from 30% to 68%. (iii) About half of the patients with NDPH according to the S-L criteria have too many migraine features to meet ICHD-2 criteria for NDPH.     

Chronic daily headache in children and adolescents: a clinic based study from India

Chronic Daily Headache (CDH) is uncommon in Indian children compared to their adult counterpart. This is a retrospective study looking at the headache phenomenology of CDH in Indian children and adolescents. The validity of the case definitions of subtypes of chronic primary headaches mentioned in the IHS 2004 classification have been evaluated. 22 children (age range 8-15 years; M : F-16 : 6) diagnosed as having primary CDH using a modified definition seen between 2002 and 2003 have been studied. CDH has been defined as daily or near daily headaches > 15d/month for > 6 weeks. The rationale for this modified definition has been discussed. Majority of children (15/22) had a more or loss specified time of onset of regular headache spells resembling New Daily Persistent Headache (NDPH) but did not fulfil totally the diagnostic criteria of NDPH as laid down by IHS 2004. In all cases headache phenomenology included a significant vascular component. Headache phenomenology closely resembled Chronic Tension Type Headache (CTTH) in 4 patients and Chronic Migraine in 3 patients. However, in no patient in these groups, a history of evolution from the episodic forms of the diseases could be elicited. Heightened level of anxiety mostly related to academic stress and achievement was noted in the majority (19/22). Only a minority of patients (3/22) had anxiety and depression related to interpersonal relationships in the family. Medication overuse was not implicated in any patient. CDH in children in India is very much different from CDH in adults with the vast majority of patients exhibiting overlapping features of migraine and tension-type headache. There is need for a modified diagnostic criteria and terminology for chronic primary headaches in children.     

Epidemiology of chronic daily headache

Daily or near-daily headache is a widespread problem in clinical practice. The general term of chronic daily headache (CDH) encompasses those primary headaches presenting more than 15 days per month and lasting more than 4 hours per day. CDH includes transformed migraine (TM), chronic tension-type headache (CTTH), new daily persistent headache (NDPH), and hemicrania continua (HC). Around 40% of patients attending a specialized headache clinic meet CDH diagnostic criteria, of which 80% are women. In these clinics about 60% of patients suffer from TM, 20% from CTTH, and 20% meet NDPH criteria. Most, some 80%, overuse symptomatic medications. One should be very cautious on extrapolating these numbers to the general population. CDH prevalence in the general population seems to be around 4% to 5% (up to 8% to 9% for women). Regarding the prevalence of CDH subtypes, NDPH is rare (0.1%), whereas the prevalence of TM (1.5% to 2%) and CTTH (2.5% to 3%) is clearly higher. In contrast to data from specialized clinics, only around a quarter of CDH subjects in the general population overuse analgesics; the prevalence of CDH subjects with analgesic overuse being 1.1% to 1.9% of the general population. Most of these patients with analgesic overuse are TM patients.     

Chronic daily headache in children and adolescents

OBJECTIVE: To describe the clinical features of children with chronic daily headache (CDH) and examine the usefulness of the International Classification of Headache Disorders-II. BACKGROUND: Few data are available on chronic daily headache and analgesic overuse in children and adolescents and there are no specific criteria for headache in children. METHODS: We retrospectively reviewed all charts of 79 children and adolescents (<16 years) with headache on > or =15 days/month presenting to the outpatient clinic of the Department of Neurology of the Leiden University Medical Center between 1994 and 2001. We classified their headaches according to the International Classification of Headache Disorders-II. RESULTS: Fifty-seven (72%) children had chronic daily headache for more than 6 months, with a duration of more than 4 hours a day in 60% of them. Quality, severity, and location of pain varied. Sixty patients (76%) used analgesics, 10 patients more than one type. Thirteen patients (16%) used analgesics daily. In one-third of patients, headache led to frequent school absenteeism and sleeping problems. Twenty-eight (35%) patients could be classified, 17 patients (22%) as chronic tension-type headache, 5 patients (6%) as chronic migraine, and 6 patients (8%) as probable medication overuse headache. Fifteen patients (19%) did not fit into any category and 36 (46%) could not be classified due to insufficient data. CONCLUSIONS: Chronic daily headache in children is a serious disorder. A relatively large number of patients overuse medication and it leads to frequent school absenteeism and sleeping problems. It remains difficult to classify their headaches with the new criteria for headache disorders.     

Chronic daily headache in a paediatric headache centre

The prevalence and the clinical features of chronic daily headache (CDH) were studied in 968 children and adolescents observed during a period of one year in the Headache Centre of the Anna Meyer Paediatric Hospital of Florence. Nine hundred and fortyfour patients (97.52%) had primary headache according to ICHD-II, 24 subjects had secondary headache and 56 patients had CDH (5.93% of primary headaches). The mean age of subjects with CDH was higher than general (13.5 vs. 11.5 years), with a female preponderance (69.6% vs. 30.4%). According to the ICHD-II, headaches were classified as chronic migraine in 10 patients (1.5.2 ICHD-II), chronic tension-type headache in 36 (2.3 ICHD-II), new daily persistent headache in 8 (4.8 ICHD-II) and 2 patients reported mixed pattern (chronic migraine+chronic tension type headache). Medication overuse was not implicated in our patients.     

Chronic daily headache: correlation between the 2004 and the 1988 International Headache Society diagnostic criteria

BACKGROUND: In a previous study, we compared the 1988 International Headache Society (IHS) criteria and the Silberstein-Lipton criteria (S-L) in a subspeciality clinic sample of 638 patients with chronic daily headache (CDH) assessed both clinically and with headache diaries. Both systems allowed for the classification of most patients with CDH. The 1988 IHS classification required multiple diagnoses and was more complex to apply. OBJECTIVES: The aim of this study was to revisit the same database, now comparing the prior classification systems with the new 2004 IHS classification. In contrast with the 1st edition, the 2nd edition includes criteria for chronic migraine (CM), new daily persistent headache (NDPH), and hemicrania continua (HC). METHODS: We reviewed the clinical records and the headache diaries of 638 patients seen between 1980 and 2001 at a headache center. All patients had primary CDH according to the S-L criteria. RESULTS: Using the S-L criteria as a reference, of the 158 patients with transformed migraine (TM) without medication overuse, just 9 (5.6%) met 2004 IHS criteria for CM. Most of the subjects were classified using combinations of migraine and CTTH diagnoses, much like the 1988 IHS classification. Similarly, using the new IHS system, just 41/399 (10.2%) subjects with TM with medication overuse were classified as probable CM with probable medication overuse. Most patients with NDPH without overuse were easily classified using the 2004 criteria (95.8%). Regarding NDPH with medication overuse, the diagnostic groups were much like results for the 1st edition. All patients with chronic tension-type headache (CTTH) and hemicrania continua (HC) according to the S-L system were easily classified using the 2004 IHS criteria. CONCLUSIONS: We conclude that the 2004 IHS criteria facilitate the classification of NDPH without medication overuse and HC. For subjects with TM according to the S-L system, the new IHS criteria are complex to use and require multiple diagnoses. Very few patients with TM in the S-L system could be classified with a single diagnosis in the 2004 IHS classification. In fact, CM was so rare that it would be virtually impossible to conduct clinical trials of this entity using the 2004 IHS criteria. Clinical trials of this entity should therefore be conducted using the S-L criteria. Finally, we propose that in the 3rd edition of the IHS classification, the diagnosis of NDPH be revised so as not to exclude migraine features.     

Management of Chronic Daily Headache: Challenges in Clinical Practice

Chronic daily headache (CHD) refers to a category of headache disorders that are characterized by headaches occurring on more than 15 days per month. This category is subdivided into long- and short-duration (>4 or <4 hours) CDH disorders based on the duration of individual headache attacks. Examples of long-duration CDH include transformed migraine (TM), chronic migraine (CM), new daily persistent headache (NDPH), acute medication overuse headache, and hemicrania continua (HC). The goal of this review is to enable clinicians to accurately diagnose and effectively manage patients with long-duration CDH. Patients with CDH often require an aggressive and comprehensive treatment approach that includes a combination of acute and preventive medications, as well as nondrug therapies.     

The International Classification of Headache Disorders revised criteria for chronic migraine—field testing in a headache specialty clinic

In the absence of a biological marker and expert consensus on the best approach to classify chronic migraine (CM), recent revised criteria for this disease has been proposed by the Headache Classification Committee of the International Headache Society. This revised criteria for CM is now presented in the Appendix. Herein we field test the revised criteria for CM. We included individuals with transformed migraine with or without medication overuse (TM+ and TM–), according to the criteria proposed by Silberstein and Lipton, since this criterion has been largely used before the Second Edition of the International Classification of the Headache Disorders (ICHD-2). We assessed the proportion of subjects that fulfilled ICHD-2 criteria for CM or probable chronic migraine with probable medication overuse (CM+), as well as the revised ICHD-2 (ICHD-2R) criteria for CM (15 days of headache, 8 days of migraine or migraine-specific acute medication use—ergotamine or triptans). We also tested the ICHD-2R vs. three proposals. In proposal 1, CM/CM+ would require at least 15 days of migraine or probable migraine per month. Proposal 2 required 15 days of headache per month and at least 50% of these days were migraine or probable migraine. Proposal 3 required 15 days of headache and at least 8 days of migraine or probable migraine per month. Of the 158 patients with TM–, just 5.6% met ICHD-2 criteria for CM. According to the ICHD-2R, a total of 92.4% met criteria for CM (P < 0.001 vs. ICHD-2). The ICHD-2R criterion performed better than proposal 1 (47.8% of agreement, P < 0.01) and was not statistically different from proposals 2 (87.9%) and 3 (94.9%). Subjects with TM+ should be classified as medication overuse headache (MOH), and not CM+, according to the ICHD-2R. Nonetheless, we assessed the proportion of them who had 8 days of migraine per month. Of the 399 individuals with TM+, just 10.2% could be classified as CM+ in the ICHD-2. However, most (349, 86.9%) had 8 days of migraine per month and could be classified as MOH and probable CM in the ICHD-2R(P < 0.001 vs. ICHD-2). We conclude that the ICHD-2R addresses most of the criticism towards the ICHD-2 and should be adopted in clinical practice and research. In the population where use of specific acute migraine medications is less common, the agreement between ICHD-2R CM and TM may be less robust.     

Field testing alternative criteria for chronic migraine

The criteria for chronic migraine (CM), as proposed by the Second Edition of the International Classification of Headache Disorders (ICHD-2) is very restrictive, excluding most patients that evolve from episodic migraine. In this study we empirically tested three recent proposals for revised criteria for CM. We included individuals with transformed migraine (TM) with or without medication overuse, according to the criteria proposed by Silberstein and Lipton. All individuals had headache calendars for at least three consecutive months. We assessed the proportion of subjects that fulfilled ICHD-2 criteria for CM or probable chronic migraine with probable medication overuse (CM+). We also tested three proposals for making the CM criteria more inclusive. In proposal 1, CM/CM + would require at least 15 days of migraine or probable migraine per month. Proposal 2 suggests that CM/CM + would be classified in those with >or= 15 days of headache per month, where at least 50% of these days are migraine or probable migraine. Proposal 3 suggests that CM/CM + would be classified in those with chronic daily headache and at least 8 days of migraine or probable migraine per month. Among TM sufferers, 399 (62.5%) had TM with medication overuse, and just 10.2% were classified as CM+ 158 (37.5%) had TM without medication overuse; just nine (5.6%) met current ICHD-2 criteria for CM. Using the alternative criteria, proposal 1 included 48.7% of patients with TM without medication overuse; proposal 2 captured 88%, and proposal 3 classified 94.9% of these patients. For TM with medication overuse, the proportions for proposals 1-3 were, respectively, 37%, 81% and 91%. The differences were statistically significant, favouring proposal 3. Consistently, criteria for CM and CM+ should be revised to require at least 8 days of migraine or probable migraine per month, in individuals with 15 or more days of headache per month.     

Migraine days decline with duration of illness in adolescents with transformed migraine

The aim of this study was to assess the proportion of subjects with transformed migraine (TM) who have 15 or more migraine days per month as a function of duration of chronic daily headache (CDH) in an adolescent sample. CDH is a syndrome characterized by 15 or more headache days per month. In specialty care, TM is the most common type of CDH. Most adults who meet criteria for TM do not meet the International Headache Society (IHS) criteria for chronic migraine (CM). TM criteria require 15 or more headache days per month (not necessarily migraine), with a current or past history of migraine. CM requires 15 or more migraine days per month. As TM develops, attack frequency increases and the number of migraine features diminishes. If this observation is correct, individuals who meet criteria for TM but not CM may be at a later stage in the evolution of the disease, compared with those who meet criteria for CM. We reviewed charts of 267 adolescents (13-17 years) seen in a headache centre, to identify 117 with TM. We divide subjects with TM into those with recent onset (1 year) and examined the number of migraine days per month and demographic features. We modelled predictors of CM (>15 migraine days per month) using logistic regression. Of 117 adolescents with TM, 55 (47%) had recent-onset (<1 year) and 62 (53%) had long-duration TM. Those with recent-onset TM were much more likely also to meet criteria for CM (74.5% vs. 25.8%, P < 0.001). This was verified in the TM with medication overuse subgroup (recent onset 66.7%, vs. long duration 37%, P = 0.01) and in the TM without medication overuse subgroup (62.2% vs. 19.2%, P = 0.001). Modelling the dichotomous outcome of CM (>15 days of migraine/month) in logistic regression, CM was predicted by recent onset of CDH, recent onset of migraine (<36 months), and younger ages (相似文献   

Chronic daily headaches in children

Chronic daily headache (CDH) is increasingly recognized as a problem in pediatrics and tertiary pediatric headache care. It is estimated that up to 4% of the adult population has CDH. Many of these are chronic migraine (CM). The fraction of the pediatric population with CDH appears to be lower, although the prevalence has not been adequately determined. The simplest definition of CDH is more than 15 headache days per month. In the International Classification of Headache Disorders, Second Edition (ICHD-II), several types of CDH have been identified. These criteria have been contrasted with the Silberstein-Lipton criteria, with revisions suggested. The diagnosis of CDH is further complicated and may be initiated by the overuse of analgesic medications (medication overuse headache) and requires the resolution of this issue before a final diagnosis can be established. In children, most CDH appears to have migraine features, although it may not completely meet the ICHD-II criteria for migraine or CM. Evaluation of CDH needs to include a complete history and physical examination to identify any possibility of the secondary headaches or headaches directly attributed to a secondary cause. Treatment and management involve a multidisciplinary approach, including acute therapy for when the headache severity increases (while avoiding medication overuse), preventative therapy to reduce the frequency and impact of the CDH, and biobehavioral therapy to assist with long-term outcome.     

Prevalence and burden of chronic migraine in adolescents: results of the chronic daily headache in adolescents study (C-dAS)

(Headache 2011;51:693‐706) Objective.— To estimate the prevalence of chronic migraine (CM) among adolescents and to describe the epidemiologic profile, headache characteristics, disability, and healthcare utilization of adolescents with CM in the USA. Background.— Chronic daily headache (CDH) and CM occur in children and adolescents, but are poorly understood in these populations because their presentation is different from that in adults. It may be difficult to assign a definitive diagnosis to young people suffering from CDH because symptoms may fail to meet the criteria for one of the CDH subtypes. Methods.— A large sample of households with at least one resident aged 12 to 19 years was selected in balance with the US Census. Data were collected in 3 phases: (1) mailed questionnaire; (2) telephone interview; and (3) 30‐day interactive voice response system diary. CM prevalence was estimated by adapting the second edition of the International Classification of Headache Disorders criteria for CM to include pediatric migraine diagnostic criteria. The population was stratified for medication overuse. Medication overuse was defined as 15 or more days per month of acute medication use. Included in the study were measures of headache characteristics, headache impact (Headache Impact Test), disability (Pediatric Migraine Disability Assessment), and healthcare and medication use. Data are reported on subjects 12 to 17 years of age only. Results.— The US adolescent (12‐17 years) prevalence rate for CM was 0.79% (0.00‐1.70) excluding those with medication overuse and 1.75% (0.62‐2.89) when adolescents with medication overuse were included. The majority of adolescents with CM had Headache Impact Test scores greater than or equal to 60, indicating severe headache impact, and mean Pediatric Migraine Disability Assessment scores greater than 17, indicating severe headache and disability. The majority of adolescents with CM (approximately 60%) had not visited a healthcare provider in the previous year and less than one in 5 reported taking medications to prevent headaches during the last month. Conclusions.— Results suggest that CM occurs less frequently in adolescents than adults, but like adults, adolescents are severely burdened by the disorder. Data support an unmet medical need; however, the development of optimal criteria for diagnosing adolescents with CM is critical to fully understanding how medical needs can be met within this complex population.     

Hemicrania Continua and Symptomatic Medication Overuse

SYNOPSIS
Hemicrania continua (HC) is a rare, strictly unilateral, non-paroxysmal headache disorder characterized by its absolute responsiveness to indomethacin. The pain is usually moderate in intensity and frequently associated with a superimposed"jabs and jolts" headache.
We report two cases of HC which presented as chronic daily headache (CDH) with abortive medication overuse.
CDH can be due to transformed migraine (TM), new daily persistent headache (NDPH), chronic tension-type headache, and HC. All can be unilateral, and all can be associated with medication overuse. Our two cases meet the criteria for HC based on indomethacin responsiveness. One meets the criteria for TM, the other NDPH. Is HC a distinct disorder, or a subset of these other disorders? CDH with medication overuse includes in its differential diagnosis HC.     

Classification of Daily and Near-Daily Headaches: Proposed Revisions to the IHS Criteria

SYNOPSIS
The International Headache Society (IHS) headache classification, while a major advance, does not adequately classify the daily and near-daily headache disorders known as chronic daily headache (CDH). We believe that chronic daily headache is a group of disorders which includes chronic tension-type headache (CTTH), transformed migraine (TM), new daily persistent headache (NDPH), and hemicrania continua (HC). We propose specific criteria for transformed migraine, new daily persistent headache, and hemicrania continua, and have modified the criteria for chronic tension-type headache.     

Chronic daily headaches: clinical profile in Indian patients

Chronic daily headache (CDH) remains a relatively unexplored entity in India. Misconceptions are common, unnecessary investigations often done and inappropriate therapy prescribed. Analgesic overuse is seldom recognized. The present report appears to be the first of its kind from India. CDH has been defined as headaches occurring more than 15 days per month for more than 3 months (secondary causes excluded). Over 2 years (1998-1999) 849 cases (49.6% of all primary headaches) were seen. More than 1 year's follow-up data were available in 205 subjects (M 34; F 171). The distribution of these was as follows: (i), chronic tension-type headache (CTH), 33 (16.1%); (ii), chronic/transformed migraine (TM), 169 (82.4%); (iii), new persistent CDH, 3 (1.5%). There were 169 cases of TM (M : F 1 : 4.7; age 26-58 years). History of past episodic migraine was present in all. Transformation had been gradual (89.4%) or acute (10.6%). Possible factors in transformation included psychological stress (44.4%), analgesic overuse (28.4%), ergot overuse (4.1%). HRT seemed to be implicated in three female subjects. Analgesic overuse was limited between intake of 600 and 2400 mg of aspirin equivalent per day (mean 735 mg). Ergot overuse varied between 1 and 3 mg/day of ergotamine for > or = 3 days/week. With medical therapy approximately 70% TM and 40% CTH patients noted significant improvement. About 80% of these relapsed on therapy withdrawal. CDH in India is not uncommon. Analgesic/ergot overuse needs to be recognized early. The average dose of analgesic implicated in CDH seems much less compared with that reported in the West.     

New daily persistent headache

New daily persistent headache (NDPH), which is the acute onset of headache within 3 days and is persistent for 15 days or more each month for at least 3 months, is a predominantly female heterogeneous subtype of chronic daily headache, typically with migraine features of unknown etiology. NDPH may be a presentation of other primary headaches such as new onset migraine, tension, or benign thunderclap headache. The headaches can be difficult to treat. The diagnosis is one of excluding the many secondary types or NDPH mimics, which is especially critical early in the course of the disease when a secondary etiology is more likely. NDPH mimics include postmeningitis headache, NDPH with medication rebound, neoplasms, temporal arteritis, chronic meningitis, chronic subdural hematoma, post-traumatic headaches, sphenoid sinusitis, hypertension, subarachnoid hemorrhage, low cerebrospinal fluid pressure syndrome, cervical artery dissections, pseudotumor cerebri without papilledema, and cerebral venous thrombosis.     

Chronic Daily Headache: Long-Term Prognosis Following Inpatient Treatment With Repetitive IV DHE

We retrospectively studied the long-term (2-year) outcome of 50 consecutive patients admitted to our inpatient headache program because of chronic daily headache (CDH) associated with the overuse of analgesics, ergotamine, or both. They had been detoxified, given repetitive intravenous dihydroergotamine (IV DHE) and prophylactic medications as part of the program, and had become headache-free on this regimen. At the time of admission, 37 of the 50 patients had transformed migraine (TM), 12 had new daily persistent headache (NDPH), and 1 had chronic tension-type headache; 29 of the patients with TM, 7 of those with NDPH, and the single patient with chronic tension-type headache had coexistent migraine. Substances abused, alone or in combination, included: caffeine in 39 patients (av. 441 mg/d), acetaminophen in 32 (av. 2187 mg/d), aspirin in 24 (av. 1807 mg/d), ibuprofen in 9 (av. 1156 mg/d), narcotics in 7 (av. 10.1 mg morphine equivalents/d) and ergotamine in 11 (av. 2.3 mg/d). Twenty patients were using preventive medication at the time of admission. Follow-up evaluations were performed at 3, 6, 12, and 24 months after discharge. Forty-three patients were analyzed at 3 months. Of these, 44% had an excellent or good result and 28% a fair result; 3 were overusing analgesics. At 24 months, 39 patients were analyzed: 59% had a good or excellent result and 28% a fair result; 5 were overusing analgesics, 4 of whom were doing poorly.(ABSTRACT TRUNCATED AT 250 WORDS)     

Kaplan Award 1998. Epidemiology of chronic daily headache in the general population

Background and Objectives.—Although chronic daily headache, mainly transformed migraine, is an important reason for consultation in headache clinics, its actual prevalence is unknown. This study analyzes the prevalence of the different types of chronic daily headache in an unselected population.
Methods.—A questionnaire exploring headache frequency was distributed to 2252 unselected subjects. Those having headache 10 or more days per month were given a headache diary and were seen by a neurologist who classified their headaches. The varieties of chronic daily headache were classified according to the second revision of IHS criteria proposed by Silberstein et al published in Neurology 1996;47:871.
Results.—The questionnaire was returned by 1883 subjects (83.5%). One hundred thirty-five admitted to headache 10 or more days per month. Chronic daily headache criteria were fulfilled by 89 individuals (4.7%). Eighty were women. Forty-two (47.2% of subjects with chronic daily headache and 2.2% of all subjects) had chronic tension-type headache. Analgesic overuse was found in 8 (17%). Transformed migraine was diagnosed in 45 (50.6% of subjects with chronic daily headache and 2.4% of all subjects). Fourteen (31.1%) individuals with this form of chronic daily headache overused ergots or analgesics. The remaining 2 cases in this series met the criteria of new daily persistent headache. No one was diagnosed as having hemicrania continua.
Conclusions.—Almost 5% of the general population (9% of women) suffers from chronic daily headache, the proportion of chronic tension-type headache and transformed migraine being quite similar. Less than one third overuse analgesics. The prevalence of chronic daily headache subtypes shown here differs from data obtained from headache clinics, emphasizing that caution is needed in extrapolating data from specialized units to the general population.     

Chronic headaches: from research to clinical practice

Chronic daily headache (CDH) is a heterogeneous group of headaches that includes primary and secondary varieties. Primary CDH is a frequent entity that probably affects 4–5% of the population. It can be subdivided into headaches of short duration (<4 h/attack) like chronic cluster headache, and disorders of long duration (>4 h/attack). Primary CDH of long duration includes transformed migraine, chronic tension–type headache, and new daily persistent headache and hemicrania continua. Analgesics, ergots and triptan overuse are frequent in all types of CDH. We revise recent insights into the epidemiology, pathophysiology, clinical characteristics and prognosis of CDH.     

Prevalence of new daily persistent headache in the general population. The Akershus study of chronic headache

The aim of the present study was to investigate the prevalence of new daily persistent headache (NDPH) in the general population, and compare the clinical characteristics of NDPH and chronic tension-type headache (CTTH). This is a population-based cross-sectional study. A random sample of 30 000 persons aged 30–44 years was drawn from the population of Akershus County, Norway. A postal questionnaire was screened for chronic headache. Those ( n  = 633) with self-reported chronic headache within the last month and/or year were invited to an interview and examination by a neurological resident. A follow-up interview was conducted after 1.5–3 years. The headaches were diagnosed according to the International Classification of Headache Disorders, 2nd edn and relevant revisions. The response rate of the questionnaire was 71% and the participation rate of the interview was 74%. Four persons, three men and one woman, had NDPH. The overall 1-year prevalence of NDPH was 0.03%. The clinical characteristics of NDPH and CTTH were similar, except for the sudden onset in NDPH. Three of the four persons with NDPH had medication overuse. Follow-up disclosed that the symptomatology of NDPH is not unchangeable, since two persons had improvement of their NDPH. NDPH is rare and occurs in one of 3500 persons from the general population of 30–44-year-olds. It is often associated with medication overuse.