New daily persistent headache in the paediatric population

We conducted a clinic-based study focusing on the clinical features of new-onset chronic daily headaches (CDH) in children and adolescents. The clinical records and headache diaries of 306 children and adolescents were reviewed, to identify 187 with CDH. Relevant information was transferred to a standardized form that included operational criteria for the diagnoses of the headaches. Since we were interested in describing the clinical features of these headaches, we followed the criteria A and B of the 2nd edn of the International Classification of Headache Disorders (ICHD-2) and refer to them as new daily persistent headaches (NDPH) regardless of the presence of migraine features (therefore, this is a modified version of the ICHD-2 criteria). From the 56 adolescents with NDPH, most (91.8%) did not overuse medications. Nearly half (48.1%) reported they could recall the month when their headaches started. NDPH was more common than chronic tension-type headache in both adolescents overusing and not overusing medication. Individuals with NDPH had headaches fulfilling criteria for migraine on an average of 18.5 days per month. On most days, they had migraine-associated symptoms (one of nausea, photophobia or phonophobia)). NDPH is common in children and adolescents with CDH. Most subjects do not overuse medication. Migraine features are common.     

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.     

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 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 tension-type headache in children and adolescents

In this study, the causes, predisposing factors and clinical features of chronic daily headache in children and adolescents were studied within the population of patients attending a specialist headache. The International Headache Society's (IHS) criteria for the diagnosis of chronic tension type headache (CTTH) were assessed for their applicability in the paediatric age group. Over a period of three years, demographic and clinical data were collected prospectively on all children who attended the clinic and suffered from daily attacks of headache. One hundred and fifteen children and adolescents (32% of all clinic population) had chronic daily headache, of whom 93 patients (81%) fulfilled the IHS criteria for the diagnosis of CTTH. They were between 3-15 years of age (mean: 11.1, SD: 2.3) and their female to male ratio was 1.2 : 1. Around one third of the patients also suffered from migraine (mainly migraine without aura). The headache was described as mild in 60.9%, moderate 36.5% and severe 2.6%. Headache was located at the forehead in 53% or over the whole of the head in 29.6%. Pain was described as 'just sore' or dull by 73.9%. During attacks of headache, at least half the patients reported light intolerance, noise intolerance, anorexia or nausea. Thirty-two percent of patients had at least one underlying chronic disease that may have contributed to the pathogenesis of the CTTH. Eleven percent had serious stressful events related to family illnesses and in four patients headaches were triggered by family bereavement. Fourteen percent were investigated with neuroimaging and 22% were referred for clinical psychology assessment and management. In conclusion, CTTH is a common cause of headache in children attending a specialist headache clinic. The clinical features closely match those of adult population and the IHS criteria for the diagnosis of CTTH can be adapted for use in children. Predisposing stressful risk factors, physical or emotional, are present in a large proportion.     

Chronic daily headache in a primary care population: prevalence and headache impact test scores

BACKGROUND: Population-based surveys estimate the prevalence of chronic daily headache (CDH) in the general community to be approximately 4%. The prevalence of CDH among patients seen in the primary care setting in the United States, however, is unknown. PURPOSE: To estimate the prevalence and associated burden of suffering of CDH in a primary care patient population. METHODS: Cross-sectional survey of a randomly selected sample of 1500 adult patients in an academic Family Medicine Center was done. Outcome measures include self-reported headache frequency and Headache Impact Test scores. RESULTS: Completed questionnaires were returned by 853 (57%) patients. The mean age of respondents was 49 years (SD = 16), with a range of 18 to 94 years. Two hundred ninety-six (58%) patients reported having had 1 or more severe headaches in the past month. Seventy-four (9%) patients reported a frequency of headache consistent with CDH, defined as the occurrence of headache 15 or more days in the past month. Twenty-four patients (32%) with CDH either believed that none of their doctors know that they experienced headaches or were not sure if their doctors were aware of their headaches, and 21 (28%) reported that they have not needed a doctor's care for their headaches. CONCLUSIONS: The prevalence of CDH is greater among a primary care patient population compared to the general community. A substantial proportion of patients with CDH do not bring their headaches to the attention of their health-care providers. In light of the advances in the development of effective medications for migraines and the growing body of evidence implicating medications as a contributing cause of CDH, it may be appropriate to encourage patients to inform their health-care providers about their headaches and to encourage providers to identify patients with frequent headaches.     

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.     

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 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 childhood and adolescence: clinical aspects and a 4-year follow-up

Chronic daily headache (CDH) represents a challenge in clinical practice and the scientific field. CDH with onset in children and adolescents represent a matchless opportunity to understand mechanisms involved in adult CDH. The aim of this study was to evaluate the diagnosis, prognosis and psychiatric co-morbidity of CDH with young onset in the young. Fifty-nine CDH patients has been followed from 1997 to 2001 in our department. Headache and psychiatric diagnoses were made on the basis of the international system of classification (International Headache Society, 1988; DSM-IV). Chi2 test and multinomial logistic regressions were applied to analyse factors predicting outcome. The current diagnostic system allows a diagnosis in 80% of CDH patients, even if age-related characteristics have been evidenced. Psychiatric disorders are notable in CDH (about 64% of patients) and predict (mainly anxiety) a poorer outcome. Surprisingly, analgesic overuse is not involved in the chronicization process. Diagnosis of CDH needs further study. Psychiatric disorders predict a worse outcome and greater account should be taken of them in treatment planning.     

Primary headaches in HIV-infected patients

Headache in patients with human immunodeficiency virus (HIV) infection may indicate life-threatening illnesses such as opportunistic infections or neoplasms. Alternatively, such patients may develop benign self-limiting headaches. Hence, defining the various types of headache in these patients is essential for proper management. This study describes the clinical characteristics of primary headaches occurring in a group of HIV-infected patients. Of 115 patients seen from 1990 to 1996, 44 (38%) had headaches. Primary headaches were present in 29 (66%) patients and secondary causes were identified in 15 (34%). Among those with primary headaches, migraine occurred in 22 (76%), tension-type headache in 4 (14%), and cluster headache in 3 (10%) patients. Half of those with migraine (n=ll), 1 patient with tension-type headache, and 1 patient with cluster headache developed chronic daily headaches which were severe and refractory to conventional headache or antiretroviral therapy. We conclude that primary headaches in patients with HIV infection are: (1) the commonest type of headache; (2) may present for the first time in individuals with severe immunosuppression; (3) usually bear no relationship to antiretroviral drug therapy; (4) polypharmacy, depression, anxiety, and insomnia are commonly associated comorbidities; (5) frequently do not respond to conventional management and carry a poor prognosis; and (6) do not require neuroradiological and/or cerebrospinal fluid evaluations.     

Classification of chronic daily headache by International Headache Society criteria: limits and new proposals

We conducted a retrospective study of 150 patients with chronic daily headache (CDH) to determine how to categorize their headache according to the classification of the International Headache Society (IHS). All patients were first evaluated at Parma and Pavia Headache Centres (from January 1992 to March 1993) and had had headache for at least 15 days a month during the previous 6 months. Four patients were thereafter excluded due to poor reliability. The 146 patients who met our CDH criteria (92 with and 54 without clear-cut migraine attacks) could be classified into four groups: (i) chronic tension-type headache (CTTH)-27 patients; (ii) coexisting migraine plus CTTH-65 patients; (iii) unclassifiable daily headache-27 patients; and (iv) migraine and an unclassifiable interval headache-27 patients. Seventy-two percent of patients with CDH had migraine as the initial form of their headache. We therefore propose to revise the IHS classification for migraine, taking into account its evolution, and add two subcategories, migraine with interparoxysmal headache and chronic migraine.     

Chronic Headache and Comorbibities: A Two‐Phase,Population‐Based,Cross‐Sectional Study

Background.— Studies using resources of a public family health program to estimate the prevalence of chronic daily headaches (CDH) are lacking. Objectives.— To estimate the 1‐year prevalence of CDH, as well as the presence of associated psychiatric and temporomandibular disorders (TMD) comorbidities, on the entire population of a city representative of the rural area of Brazil. Methods.— This was a cross‐sectional, population‐based, 2‐phase study. In the first phase, health agents interviewed all individuals older than 10 years, in a rural area of Brazil. In the second stage, all individuals who reported headaches on 4 or more days per week were then evaluated by a multidisciplinary team. CDH were classified according to the second edition of the International Classification of Headache Disorders (ICHD‐2). Medication overuse headache was diagnosed, as per the ICHD‐2, after detoxification trials. Psychiatric comorbidities and TMD were diagnosed based on the DSM‐IV and on the Research Diagnostic Criteria for Temporomandibular Disorders criteria, respectively. Results.— A total of 1631 subjects participated in the direct interviews. Of them, 57 (3.6%) had CDH. Chronic migraine was the most common of the CDH (21, 36.8%). Chronic tension‐type headache (10, 17.5%), medication overuse headache (13, 22.8%) and probable medication overuse headache (10, 17.5%) were also common. Psychiatric disorders were observed in 38 (67.3%) of the CDH subjects. TMD were seen in 33 (58.1)% of them. Conclusions.— The prevalence of CDH in the rural area of Brazil is similar to what has been reported in previous studies. A significant proportion of them have psychiatric comorbidities and/or TMD. In this sample, comorbidities were as frequent as reported in convenience samples from tertiary headache centers. (Headache 2010;50:1306‐1312)     

Chronic daily headache. How should it be included in the IHS classification?

A number of patients attending specialty headache centers complain of very frequent, almost continuous or continuous headaches, which are usually grouped together under the term chronic daily headache , a category which does not appear in the International Headache Society (IHS) classification. On the basis of the IHS criteria, these patients can only be classified as having a chronic tension-type headache with the possible addition of migraine, if migrainous attacks are superimposed on the "background" headache. However, several studies have demonstrated that most patients with chronic daily headache originally suffered from migraine and that their migraine has transformed, in the course of time, into a chronic headache picture in which isolated migraine attacks may or may not persist. Despite some differences in the personal opinions of authors involved in the care of patients with chronic daily headache, some views seem to be generally accepted: (1) the great majority of chronic daily headaches are transformations of an original episodic migraine and cannot be included in the chronic tension-type headache category, (2) the current IHS classification does not allow many patients presenting with chronic daily headache to be classified correctly, (3) an important nosological category (transformed migraine) has emerged from all the studies on this subject, (4) it is impossible to diagnose transformed migraine merely by "photographing" the picture of single attacks. Although some theoretical problems remain unresolved, it seems to us that the next revision of the IHS classification can no longer ignore the existence of chronic daily headache.     

Elevation of CSF tumor necrosis factor alpha levels in new daily persistent headache and treatment refractory chronic migraine

OBJECTIVE: To determine if patients with new daily persistent headache (NDPH) have elevated levels of tumor necrosis factor alpha (TNF alpha) in the CSF. BACKGROUND: NDPH is considered one of the most treatment resistant of all headache syndromes. This reflects a lack of understanding of its pathogenesis. As a certain percentage of NDPH patients have their headaches start after an infection, the possibility of a persistent state of systemic or CNS inflammation comes into question. TNF alpha is a proinflammatory cytokine involved in brain immune and inflammatory activities, as well as in pain initiation. The goal of this study was to look at TNF alpha levels in the CSF of NDPH patients, to determine if CNS inflammation may play some role in the pathogenesis of this condition. METHODS: CSF TNF alpha levels were studied in 38 patients: 20 with NDPH and a control population of 16 patients with chronic migraine (CM), and 2 with post-traumatic headache (PT). RESULTS: CSF TNF alpha levels were elevated in 19 of 20 NDPH patients, 16 of 16 CM patients, and both PT patients. Serum TNF alpha levels were normal in most of the study subjects. CONCLUSION: An elevation of CSF TNF alpha levels was found in almost all NDPH patients and suggest a role for TNF alpha in the pathogenesis of this condition. Surprisingly, all CM and PT patients tested had elevated CSF TNF alpha levels. In most patients with elevated CSF levels, serum TNF alpha levels were normal. All of these syndromes may be manifestations of CNS inflammation. As most of the positive-tested patients showed minimal to no improvement during aggressive inpatient treatment, persistent elevation of CSF TNF alpha levels may be one of the causes of treatment refractory 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.     

Clinical features, effectiveness of drug-based treatment, and prognosis of new daily persistent headache (NDPH): 30 cases in Japan

Although new daily persistent headache (NDPH) is considered to be one of the most refractory headaches to pharmacological treatment, the effectiveness of drug-based treatment, and the prognosis of NDPH have not been well studied. The purpose of this study is to evaluate the effectiveness of pharmacological treatment of NDPH. Seventeen men and 13 women who met the IHS diagnostic criteria for NDPH, were treated for five years from November 1997 to October 2002, and whose headache conditions were entirely available for reference as of October 2003 were investigated in Toyonaka Municipal Hospital. Mean age at onset 35.0 years (range 13-73 years). The onset of headache occurred in relation to a stressful life event in six (20%) patients and any precipitating events could not be identified in 24 (80%) patients. For treatment, muscle relaxants were first administered and if no effect was observed, tricyclic antidepressants, selective serotonin reuptake inhibitors, and antiepleptic drugs were subsequently administered. Results of the drug-based treatments in the 30 cases were 'very effective' for eight (27%) cases, 'moderately effective' for one (3%) case, 'mildly effective' for six (20%) cases, and 'not effective' for 15 (50%) cases. According to the survey on the phone for the patients who did not improve to the level of 'mildly effective' or better and did not come back to our institution as of October 2003, there were no cases found to have spontaneously improved to the level of 'mildly effective' or better. These results suggest that NDPH is highly recalcitrant to the treatments with poor prognosis and better treatments are needed.     

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.     

Chronic daily headache in a tertiary care population: correlation between the International Headache Society diagnostic criteria and proposed revisions of criteria for chronic daily headache

The International Headache Society (IHS) has been criticized for its approach to classification of chronic daily headache (CDH); Silberstein and Lipton criteria provide an alternative to this approach. The aim of this study is to apply the alternative diagnostic approaches to a sample of CDH patients consulting in specialty care. Our sample consisted of 638 patients with CDH. Patients were classified according to both classification systems. Patients were predominantly female (65.0%), with ages ranging from 11 to 88 years. According to the Silberstein and Lipton classification, we found eight different diagnoses. The most common diagnosis was chronic migraine (87.4%), followed by new daily persistent headache (10.8%). Just six patients had chronic tension-type headache (CTTH). Applying the IHS criteria we found 14 different diagnoses. Migraine was found in 576 (90.2%) patients. CTTH occurred in 621 (97.3%), with only 10 (1.57%) having this as the sole diagnosis. We conclude that both systems allow for the classification of most patients with CDH when daily headache diaries are available. The main difference is that the IHS classification is cumbersome and requires multiple diagnoses. The Silberstein and Lipton system is easier to apply, and more parsimonious. These findings support revision of the IHS classification system to include chronic migraine.     

Past, present, and future prospects of medication-overuse headache classification

The 1988 classification by the International Headache Society (IHS) first defined drug-induced headache as a specific disorder, belonging to secondary headaches, subtype 8.2 (headache induced by chronic substance use or exposure). In 2004 ICHD-II, this definition was replaced by medication-overuse headache (MOH). It was established that a definite diagnosis of MOH required the improvement of the disorder after cessation of medication overuse. The specific characteristics of the various subforms were also indicated. Later revisions have first eliminated these headache characteristics and then the diagnosis of probable MOH. The diagnosis of MOH has therefore become more useful to clinical aims. However, the last revision has eliminated the need to prove that the disorder is caused by drugs, that is, the headache improves after cessation of medication overuse. The classification of MOH as a secondary headache has therefore been modified, too. Clinical trials can consequently include in the same group patients with primary headache and drug overuse and patients with MOH.
We therefore propose to continue to use the diagnosis of probable MOH to research aims. We also propose to modify the classification of MOH subforms according to the presence or absence of a dependence-producing property of overused drugs. This will allow to better analyze the role of the various medications in inducing chronic headache and the outcomes of treatments.