Hemicrania continua: clinical review, diagnosis and management

Hemicrania continua with rhinosinusitis: a case report

Hemicrania continua (HC) is an indomethacin-responsive headache, characterized by unilateral and continuous headaches with cranial autonomic symptoms. Various pathologies, including sinus-related conditions, are associated with HC. Here, we report the case of a 62-year-old man with HC and rhinosinusitis. The patient complained of a unilateral continuous headache with ipsilateral cranial autonomic symptoms, conjunctival injection, and eyelid edema for 20 months. HC was identified as a potential diagnosis based on the symptom criteria, and a response to indomethacin confirmed the diagnosis. Trigeminal autonomic cephalalgia should be considered in patients with unilateral headaches and cranial autonomic symptoms.

Pharmacological Dissociation in Hemicrania Continua With Persistent Visual Aura Evolved From Episodic Migraine: A Case Report

OBJECTIVE

To report a case of hemicrania continua (HC) and persistent visual aura without infarction in a patient with previous episodic migraine with visual aura, whose persistent aura symptoms improved only after treatment with divalproex sodium.

BACKGROUND

Once regarded as highly specific for migraine, visual aura has been associated with trigeminal autonomic cephalalgias, including HC. In previous descriptions of HC and episodes of typical visual aura, the aura occurred exclusively with severe headache exacerbations and, like the pain, resolved with indomethacin.

METHODS

Case report and literature review.

RESULTS

A 54-year-old man with a history of episodic migraine with visual aura reported a gradual onset of HC with persistent visual aura of 15 months duration. General medical and neurological examinations were normal, including imaging studies. HC's headache responded to indomethacin, while the visual aura was recalcitrant, only improving with oral divalproex sodium treatment.

CONCLUSION

As our patient experienced HC, which evolved from episodic migraine, we hypothesize that migraine and HC may share a common pathophysiology. However, the persistence of the visual aura, despite the abolition of pain and autonomic features with a therapeutic dose of indomethacin, and the subsequent successful treatment of the aura with divalproex sodium, suggest that aura and HC headache arise from distinct and dissociable mechanisms.

Feasibility of a High-Dose Inhaled Indomethacin Dry Powder with Dual Deposition for Pulmonary and Oral Delivery

In this study we have developed a high-dose dry powder inhaler formulation of indomethacin using a novel approach to carrier-based formulations. Specifically, larger drug particles serve as the carrier for the smaller micronized drug particles, such that an inhaled dose is combined with an oral dose. To study this system, the aerosol performance of a standard indomethacin-lactose formulation was compared to carrier-free micronized indomethacin and a drug-as-carrier formulation (a micronized indomethacin-coarse indomethacin blend). Indomethacin with lactose showed a very poor aerosol performance, indicating high adhesion between the drug and carrier. The performance of the carrier-free micronized drug was significantly better, indicating low cohesion. Coarse drug particles as a carrier allowed improved powder flow and aerosol performance while also providing a potential secondary route of absorption of indomethacin, namely oral. An optimal formulation ratio of 1:1 (w/w) fine indomethacin-coarse indomethacin was developed in this study.

The critical role of neuroimaging in hemicrania continua: A systematic review and case series

BACKGROUND

Hemicrania continua is a primary unilateral headache characterized by ipsilateral parasympathetic and sympathetic autonomic features. A key diagnostic criterion is its dramatic response to indomethacin treatment; however, various vascular or structural abnormalities have been reported to cause secondary hemicrania continua, presenting with clinical features similar to those of the primary headache presentation.

OBJECTIVE

We reviewed the literature to compile secondary hemicrania continua cases, highlighting the importance of imaging during the evaluation. Additionally, we also contributed our three cases to the existing studies.

METHODS

We conducted a review of articles from the PubMed and EMBASE databases that described reported cases of secondary hemicrania continua, covering the period from 1993 to 2021. Our review included detailed patient information, signs, and symptoms of hemicrania continua, as well as information on indomethacin usage and headache resolution (if pertinent).

RESULTS

Secondary hemicrania continua can result from a remarkably diverse range of structural and vascular lesions, yet clinical reports on long-term follow-up are lacking. Notably, cases may exhibit a classical response to indomethacin, emphasizing the importance of neuroimaging in excluding secondary cases. Our search yielded 41 cases meeting our criteria. We excluded six cases that were not treated with indomethacin or were unresponsive to it. Additionally, we present three cases that highlight the necessity of neuroimaging in evaluating hemicrania continua, along with short- and long-term clinical outcomes following indomethacin and lesion-directed treatments. Case 1 presented with daily right-sided headaches and cranial autonomic symptoms. Her pain completely resolved with indomethacin use. Neuroimaging of the brain revealed a laterally directed saccular aneurysm of the right internal carotid artery. Case 2 presented with continuous left-sided unilateral headaches with superimposed exacerbations. She complained of left-sided photophobia with a dull sensation in the left ear. Her symptoms decreased after 2 weeks of indomethacin use. Neuroimaging of the head indicated a benign tumor with mass effect into the left lateral medulla and inferior cerebellar peduncle. Case 3 presented with a right side-locked headache with daily, severe superimposed exacerbations. She had photophobia in the right eye and a right-sided Horner's syndrome, along with tearing during her exacerbations. Neuroimaging of the brain revealed a pituitary tumor and her pain completely resolved with indomethacin.

CONCLUSION

Hemicrania continua is a rare headache disorder that can be either primary or secondary. Importantly, response to indomethacin can still occur in secondary hemicrania continua. Thus, neuroimaging should be considered to rule out underlying structural etiology in all cases, regardless of their clinical responsiveness to indomethacin therapy.

Melatonin in hemicrania continua and paroxysmal hemicrania

BACKGROUND

Hemicrania continua (HC) and paroxysmal hemicrania (PH) belong to a group of primary headache disorders called trigeminal autonomic cephalalgias. One of the diagnostic criteria for both HC and PH is the absolute response to the therapeutic dose of indomethacin. However, indomethacin is discontinued in many patients as a result of intolerance to its side effects. Melatonin, a pineal hormone, which shares similar chemical structure to indomethacin, has been reported to have some efficacy for HC in previous case reports and series. To our knowledge, there is no literature regarding the use of melatonin in PH. We aimed to describe the clinical use of melatonin in the preventive management of HC and PH.

METHODS

Patient level data were extracted as an audit from routinely collected clinical records in consecutive patients seen in outpatient neurology clinic at King's College Hospital, London, UK, from September 2014 to April 2023. Our cohort of patients were identified through a search using the keywords: hemicrania continua, paroxysmal hemicrania, melatonin and indomethacin. Descriptive statistics including absolute and relative frequencies, mean ± SD, median and interquartile range (IQR) were used.

RESULTS

Fifty-six HC patients were included with a mean ± SD age of 52 ± 16 years; 43 of 56 (77%) patients were female. Melatonin was taken by 23 (41%) patients. Of these 23 patients, 19 (83%) stopped indomethacin because of different side effects. The doses of melatonin used ranged from 0.5 mg to 21 mg, with a median dose of 10 mg (IQR = 6-13 mg). Fourteen (61%) patients reported positive relief for headache, whereas the remaining nine (39%) patients reported no headache preventive effect. None of the patients reported that they were completely pain free. Two patients continued indomethacin and melatonin concurrently for better symptom relief. Eight patients continued melatonin as the single preventive treatment. Side effects from melatonin were rare. Twenty-two PH patients were included with mean ± SD age of 50 ± 17 years; 17 of 22 (77%) patients were female. Melatonin was given to six (27%) patients. The median dose of melatonin used was 8 mg (IQR = 6-10 mg). Three (50%) patients responded to melatonin treatment. One of them used melatonin as adjunctive treatment with indomethacin.

CONCLUSIONS

Melatonin showed some efficacy in the treatment of HC and PH with a well-tolerated side effect profile. It does not have the same absolute responsiveness as indomethacin, at the doses used, although it does offer a well-tolerated option that can have significant ameliorating effects in a substantial cohort of patients.

Hemicrania Continua: An Update

PURPOSE OF REVIEW

Hemicrania Continua (HC) is a rare and disabling primary headache disorder that is characterized by persistent, unilateral headache with ipsilateral, cranial autonomic symptoms and restlessness or agitation. The diagnosis requires patients to experience an absolute response to therapeutic doses of indomethacin.

RECENT FINDINGS

HC is diagnosed in in about 1.8% of adult patients who were evaluated for headache in tertiary care services, albeit this estimate should be interpreted with caution. The most prevalent accompanying symptoms appear to be lacrimation, conjunctival injection and restlessness or agitation. However, the available literature is limited by methodologic issues, and the current diagnostic criteria lack clarity on what defines absolute response to indomethacin. More rigorous studies are thus needed to improve our understanding of HC which, in turn, will facilitate better disease management in clinical practice. Here, we provide a comprehensive overview of HC, including its epidemiology, clinical presentation, diagnostic evaluation, and management.

Prevalence and clinical features of hemicrania continua in clinic-based studies: A systematic review and meta-analysis

OBJECTIVE

To estimate the relative frequencies of hemicrania continua and its clinical features in adult patients who were evaluated for headache in a clinic-based setting.

METHODS

PubMed and Embase were searched for observational, clinic-based studies published between 1 January 2004 and 1 February 2022, that reported on the relative frequencies of hemicrania continua and its clinical features. Two independent investigators (HMA and SA-K) screened titles, abstracts, and full text-articles. A random-effects meta-analysis was conducted to estimate pooled relative frequencies of hemicrania continua and its clinical features across clinic-based studies.

RESULTS

Eleven clinic-based studies were deemed eligible for inclusion. Of these, eight studies reported on the relative frequency of hemicrania continua among adult patients (n = 9854) who were evaluated for headache in a tertiary care unit. The pooled relative frequency of hemicrania continua was found to be 1.8% (95% CI; 1.0-3.3). Considerable heterogeneity was noted across studies (I² = 89.8%). The three most common symptoms associated with hemicrania continua were lacrimation (72.3%), conjunctival injection (69.8%), and restlessness/agitation (60.2%).

CONCLUSION

The findings of this meta-analysis suggest that there is limited epidemiologic data on the relative frequencies of hemicrania continua and its clinical features. Standardized data acquisition and reporting are needed to estimate prevalence rates more accurately and to better understand epidemiologic patterns. This, in turn, should increase awareness of the impact that hemicrania continua has in clinical practice.

An Update on Diagnosis and Pharmacologic Therapy for Headache in the Oral and Maxillofacial Surgery Practice

Headaches are synonymous with neurovascular pain (cephalalgias), which comprise a heterogeneous group of pain disorders that share a common anatomic region (head and neck). Headaches are often a "universal" disease presentation that is evaluated by the oral and maxillofacial surgeon. Pharmacologic therapy of headaches is most often based on the severity of symptoms and the degree of disability experienced by the patient. This article describes the epidemiology of neurovascular headaches, their pathophysiologic mechanisms/presentation, the workup of patients, and an up-to-date overview of pharmacologic approaches that can be applied in the oral and maxillofacial surgical practice to treat this patient population.

Temporary resolution of hemicrania continua following ipsilateral ear piercing

BACKGROUND

Hemicrania continua is an uncommon subtype of trigeminal autonomic cephalgia that exhibits dramatic therapeutic response to indomethacin. Unfortunately, indomethacin is associated with a range of adverse effects, including neuropsychiatric complications, which limits its use in many patients. Although no other effective pharmacologic agents exist, there is emerging evidence for interventional treatments such as occipital nerve and vagus nerve stimulation, which may act by modulating neural activity within the trigeminovascular system.

CASE

We present a 30-year-old woman with long-standing refractory hemicrania continua who suffered adverse effects to indomethacin. She experienced temporary, but near-complete, symptom resolution following piercing of the crus of the ear helix ipsilateral to her headache, whereas contralateral piercing produced no benefit.

CONCLUSIONS

To our knowledge, this case is the first to describe a therapeutic benefit following ear piercing in a patient with trigeminal autonomic cephalgia. We argue that symptom relief was obtained through a similar mechanism to occipital or vagus nerve stimulation.

Hemicrania Continua: An Update

Background

Hemicrania continua (HC) is not uncommon in clinical practice, and several large case series have been published in the recent past.

Objectives

This review provides an overview of the recent advancement in different aspects of HC.

Methods

We reviewed the articles published on HC in the last 2 decades.

Results

HC constitutes 1.7% of patients with headache in the clinics. It presents with unilateral continuous background pain with periodic exacerbations, usually accompanied by cranial autonomic features and restlessness. The continuous background headache is the most consistent and central feature of HC. Although the duration of exacerbations varies from a few seconds to a few weeks, the frequency ranges from >20 attacks/day to one attack in several months. The background pain is mild to moderate in intensity and does not hamper routine activity. Patients and physicians frequently ignore the basal pain, and a case of HC is misdiagnosed as other headaches, depending on the pattern of exacerbations. The exacerbation mimics several primary headaches and neuralgias. There are about 75 cases of secondary HC, due to 29 different pathologies. Although an absolute response to indomethacin is part of the diagnostic criteria, a subset of patients may respond to several other drugs. Headache reappears immediately on skipping a single dose of effective drug. Several surgical procedures have been tried in patients who are intolerant to indomethacin.

Conclusion

Misdiagnosis of HC is common. Continuous background pain and response to indomethacin are two essential features for the diagnosis of HC.

The Promising Effect of Nerve Decompression in Trigeminal Autonomic Cephalalgias: Report of Case Series

Trigeminal Autonomic Cephalalgias (TAC) are excruciating headaches with limited treatment options. The chronic forms of TACs, including chronic cluster, chronic paroxysmal hemicrania, and hemicrania continua, are disabling conditions. In addition to drug therapy, there are some studies regarding nerve blocking and nerve stimulation with acceptable results. Here we report four cases of decompression nerve surgery with promising results on pain control in these difficult to treat headaches.

Secondary hemicrania continua-tic syndrome associated with fungal sphenoiditis: A case report

The coexistence of hemicrania-continua and trigeminal neuralgia is called HC-tic syndrome. We describe a case of an elderly man who suffered both types of headache related to fungal sphenoiditis. This is the first case to be reported, to the best of our knowledge.

Hemicrania Continua and Pituitary Microadenoma - Post Hoc Ergo Propter Hoc?: A Case Report With a Side Note on Intra-Sellar Pressure and the Trigemino-Autonomic Reflex

We describe the case of a 38-year-old woman whose headache phenotype transformed from episodic migraine to hemicrania continua (HC) responsive to indomethacin, as expected per diagnostic criteria. Our patient also had a non-functioning pituitary micro-adenoma which is over-represented in the trigeminal autonomic cephalgias (TAC) such as HC, pituitary adenoma being the most common intra-cranial pathology. We explore our case further by outlining in detail the neural supply of the dura of the pituitary fossa, outline the dynamics of intra-sellar pressure (ISP), and posit potential mechanisms of generation of HC in patients with pituitary micro-adenoma. We stress and further explore the remarkable observation that indomethacin, which lowers intracranial pressure, exquisitely resolves the pain of HC. Furthermore, we hypothesize that despite normal ISP, the slight elevation of ISP and mass effect impairs portal venous circulation, which may lead to venous hypertension and/or parasympathetic hyperactivity, which explains the pain and autonomic features of HC.

Why is it important to diagnose hemicrania continua?

Hemicrania continua (HC) is an indomethacin-responsive primary headache which belongs to the trigeminal autonomic cephalalgias. Although the first description of HC was 35 years ago, there are still different views regarding the clinical course, the diagnostic criteria, and the treatment. The high clinical heterogeneity of HC, missed diagnosis, and the delay to the correct diagnosis are important in patient care. Central features of HC are continuous side-locked headaches (with superimposed exacerbations) and the response to indomethacin. We are describing the case of a 29-year-old women who developed right-sided headache 3 weeks after the excision of a right-sided vestibular schwannoma. She tried different painkillers and also was started on a prophylactic treatment with oxcarbazepine, acupuncture, and physiotherapy. But nothing really helped. She was then admitted for an inpatient withdrawal program for medication overuse headache. Again the pain did not change. She has then been treated with indomethacin 50-mg tds, where after the headache improved rapidly within 3 days. This educational case presentation and review of the literature aims to consider HC as a possible differential diagnosis in chronic headache, especially when side-locked and shows that indomethacin maybe a quick therapeutic option before putting the patients on a long treatment odyssey with analgesics and other drugs.

Headache in the elderly

Headache is the most common neurologic symptom and affects nearly half the world's population at any given time. Although the prevalence declines with age, headache remains a common neurologic complaint among elderly populations. Headaches can be divided into primary and secondary causes. Primary headaches comprise about two-thirds of headaches among the elderly. They are defined by clinical criteria and are diagnosed based on symptom pattern and exclusion of secondary causes. Primary headaches include migraine, tension-type, trigeminal autonomic cephalalgias, and hypnic headache. Secondary headaches are defined by their suspected etiology. A higher index of suspicion for a secondary headache disorder is warranted in older patients with new-onset headache. They are roughly 12 times more likely to have serious underlying causes and, frequently, have different symptomatic presentations compared to younger adults. Various imaging and laboratory evaluations are indicated in the presence of any "red flag" signs or symptoms. Head CT is the procedure of choice for acute headache presentations, and brain MRI for those with chronic headache complaints. Management of headache in elderly populations can be challenging due to the presence of multiple medical comorbidities, polypharmacy, and differences in drug metabolism and clearance.

Trigeminal autonomic cephalalgias presenting in a multidisciplinary tertiary orofacial pain clinic

Abstract

Orofacial pain may have a variety of causes and offers a significant clinical challenge for its diagnosis and management.

Objective

To assess the headache disorders presenting in a tertiary multidisciplinary orofacial pain clinic, after dental causes have been excluded.

Methods

Clinic letters from the initial consultation and subsequent follow up reviews of the 142 patients, who were seen in the tertiary Multidisciplinary Orofacial Pain clinic between January 2015 until January 2018 were reviewed as a clinical audit.

Results

The most common diagnoses were possible trigeminal autonomic cephalalgia (n = 62, 44%), migraine (n = 38, 27%) and painful post-traumatic trigeminal neuropathy (n = 17, 12%). The most common trigeminal autonomic cephalalgia diagnosis was hemicrania continua (n = 13, 9%), which is higher than the reported prevalence in neurology and headache clinics.

Conclusion

This study demonstrates the importance of a multidisciplinary approach to diagnosing complex orofacial pain patients and the importance of awareness of primary headache disorders, in particular trigeminal autonomic cephalalgias, thereby reducing unnecessary diagnostic delays or procedures.

A case of remitting hemicrania continua with seasonal variation and clustering: a diagnostic confusion with cluster headache

Hemicrania continua (HC) is an indomethacin responsive primary headache that is characterised by a continuous strictly unilateral headache with periodic exacerbations. About 15% may have a remitting subtype of HC. Herein, we are reporting a 36-year-old man who had a 5-year history of episodic right-sided headaches. The headaches used to occur in a discrete series lasting 4-6 weeks, separated by pain-free remissions of 10-11 months. In each relapse, he had continuous background pain with superimposed exacerbations. The superimposed exacerbations were 1-2 attacks per day, lasting for 2-5 hours, and were associated with ipsilateral cranial autonomic symptoms. However, the patient did not respond to usual therapies of custer headache (CH). He had a complete response to indomethacin. We suggest that remitting subtype of HC may mimic CH. A therapeutic trial of indomethacin should be done in all strictly unilateral headaches who are not responding to other drugs.

The Exacerbation of Hemicrania Continua Mimics Trigeminal Neuralgia

We report the case of a 46-year-old man with hemicrania continua presenting as exacerbations mimicking trigeminal neuralgia. The patient was tentatively diagnosed with trigeminal neuralgia, and treatment with various combinations of drugs was performed after the onset of pain. However, when the condition of the patient did not improve, we suspected hemicrania continua, and treatment with indomethacin was initiated. There was a marked alleviation of his pain within 24 hours. Thus, clinicians should be aware that the duration and frequency of exacerbations of hemicrania continua are variable.

A long-term prospective observational study in 31 patients with hemicrania continua

Introduction:

Till date, there is no prospective study in patients with hemicrania continua (HC).

Methods:

Patients fulfilling the international classification of headache disorders criteria for HC were evaluated prospectively. All patients were subjected to a detailed clinical interview, based on a structured questionnaire. Before starting indomethacin, all patients were instructed to fill a headache diary for at least 5 days. Gradual tapering of indomethacin was done at regular intervals.

Results:

We enrolled 41 patients over 4.5 years, 31 of whom met the criteria after confirming the indomethacin response. The mean age was 41 years, and 55% were female. The mean duration of headache was 43.6 months. All patients had continuous strictly unilateral pain with episodic exacerbations. At least one cranial autonomic feature was noted in 81% of patients. Twenty-five patients (81%) felt a sense of restlessness during exacerbations. The mean follow-up was 2.5 years. Three-fourths of patients noted a reduction in indomethacin dose after an average 2.5 of years follow-up. The mean reduction of the dose in the follow-up was statistically significant (172 mg vs. 110 mg, p < 0.001). All patients missed the drug for various reasons over the observation period. The headache reappeared within 48 h in 97% of patients.

Conclusion:

Misdiagnosis of HC is still very common. Patients may not volunteer about the background pain and will focus only on the exacerbations. HC rarely remits, but indomethacin requirements may decrease over time. Skipping of the effective drug leads to the immediate reappearance of pain.

Hemicrania Continua: a Clinical Perspective on Diagnosis and Management

PURPOSE OF REVIEW

Hemicrania Continua (HC) is a daily and persistent form of headache that is characterized by side-locked pain which is continuous, varies in severity and can be associated with conjunctival injection, lacrimation, nasal congestion, rhinorrhea, eyelid edema, forehead or facial sweating and miosis and/or ptosis.

RECENT FINDINGS

Functional imaging studies have shown activation of subcortical structures such as the posterior hypothalamus and dorsal rostral pons, which are known to disinhibit the trigeminal autonomic reflex, a reflex responsible for autonomic outflow through trigeminal efferents. A similar pathway activation is seen in other Trigeminal autonomic cephalalgias (TAC) which solidifies HC as a TAC. While we also discuss promising treatments in our review, more evidence is needed before making them a standard of therapy for HC. This article aims to review the recent research on the diagnosis and clinical management of this potentially underdiagnosed primary headache disorder.

Herpes zoster ophthalmicus evolving into headache characterised as hemicrania continua

Postherpetic neuralgia (PHN) is the most common chronic complication of herpes zoster infection. However, a few patients may develop different types of pain after herpetic lesions. We are reporting two patients who developed postherpetic hemicrania continua (HC). Case 1: a 54-year-old woman had a 10-month history of continuous left-sided pain with superimposed exacerbations. The pain started with the onset of herpetic lesions in the ophthalmic division. The lesions subsided in a few weeks. However, the pain persisted and it responded exclusively to indomethacin. Case 2: a 61-year-old woman developed clinical features pertinent to PHN. However, later on, the pattern and associated clinical features changed. The patient fulfilled the criteria of HC and showed a complete response to indomethacin. We suggest that every patient with PHN should be asked for cranial autonomic features and a trial of indomethacin should be given in refractory herpes zoster neuropathy.

Hemicrania continua: Case series presenting in an orofacial pain clinic

AIM OF INVESTIGATION

Hemicrania continua (HC) is an uncommon primary headache and little is known of the characteristics of such patients managed in an orofacial pain setting. This study provides clinical features of HC, its association with other disorders, and treatment outcomes of patients managed in the TMD and Orofacial Pain Clinic at the University of Minnesota.

METHODS

A retrospective review of patient records was undertaken. Inclusion criteria were a diagnosis of HC and confirmation at follow-up.

RESULTS

Six of the 1617 new patients seen between 2015 and 2017 met the selection criteria. Four patients presented with "facial pain", one with "toothache" and one with "jaw pain". All were female with mean age 55 ± 10.5 years (range = 41-69). Headache characteristics included unilateral (R:L = 1:1) pain of moderate intensity with severe exacerbations in the distribution of V₁ (1/6), V₁ + V₂ (3/6) and V₁ + V₂ + V₃ (2/6). Lacrimation and photophobia were the most common associated symptoms. Patient presentations were complicated by multiple medical and comorbid diagnoses. All were diagnosed with temporomandibular disorder (TMD). Indomethacin alone was sufficient for adequate headache control in 2/6 patients with several add-on medications providing sustained pain relief.

CONCLUSIONS

Comorbid pain conditions can be expected in patients with HC presenting to orofacial pain clinics. Symptom presentation varies, and multimodal treatment approach is necessary for success.

Hemicrania Continua

Hemicrania continua (HC) is an indomethacin responsive primary chronic headache disorder which is currently classified as a subtype of trigeminal autonomic cephalalgias (TACs). It is not very uncommon. There are >1000 cases of HC in the literature, and it constitutes 1.7% of total headache in the clinic settings. Misdiagnosis for HC is very common at all clinical settings. A diagnosis of HC is missed even by neurologists and headache specialists. It is characterized by a continuous strictly unilateral headache with superimposed exacerbations. Just like other TACs, exacerbations are associated with cranial autonomic symptoms and restlessness. A large number of patients may have migrainous features (nausea, vomiting, photophobia, and phonophobia) during exacerbations phase. The “key” feature of HC is persistent featureless background headaches. However, patients and physicians may focus only on the exacerbation part. As durations, frequency and associated symptoms of exacerbations are highly variables; it may mimic a large number of primary and secondary headache disorders. Migraine and cluster headache are two most common misdiagnosed conditions. Another specific feature of HC is remarkable repose to indomethacin. A “complete” response to indomethacin is as “sine qua non” for HC. However, a few other medications may also be effective in a subset of HC patients. Various surgical procedures have been tried with mixed results in patients who were intolerant to indomethacin or other drugs.

Headache

Headache, an almost universal human experience, is one of the most common complaints encountered in medicine and neurology. Described and categorized since antiquity, with the first classification by Aretaeus of Cappadocia, other classifications followed. The evaluation of this condition may be straightforward or challenging, and, though often benign, headache may prove to be an ominous symptom. This review discusses the current diagnosis and classification of headache disorders and principles of management, with a focus on migraine, tension-type headache, trigeminal autonomic cephalgias, and various types of daily headache.