Nummular Headache testBrian M. Grosberg, MD, Seymour Solomon, MD, and Richard B. Lipton, MDCorresponding authorBrian M. Grosberg, MDMontefiore Headache Center, 1575 Blondell Avenue, Suite 225, Bronx, NY 10461, USA.E-mail: email@example.comCurrent Pain and Headache Reports 2007, 11:310-312 Current Medicine Group LLC ISSN 1531-3433Abstract Nummular headache is a rare primary headache disorder characterized by focal andwell-circumscribed pain fixed within a round-, oval-, or elliptical-shaped region of the head. Thepain is usually mild to moderate in intensity but may be severe. Nummular headache is mostcommon in women in the fourth to fifth decade of life. The temporal pattern may be chronicand continuous since onset, chronic evolved from episodic, or episodic. These headachestypically are unilateral, side-locked, and fixed in location, commonly affecting the parietalregion. Many patients experience superimposed exacerbations of pain, lasting from seconds todays. Sensory phenomena, such as parenthesis, allodynia, and dysesthesias, are frequentlyreported in the region of the pain. Treatment with gabapentin, tricyclic antidepressants, orbotulinum toxin may be helpful.Introduction Derived from the Latin word for "coin," the term nummular headache was firstintroduced in 2002, when Parejaet al.  described a series of 13 patients with well-circumscribed pain confined to a round-, oval-, or elliptical-shaped region of the head in theirnow classic paper in Neurology. Two years later, the same group reported a series of 14additional patients [2.0]. Based largely on these reports by Parejaet al., nummular headachewas included in the appendix of the second edition of the International Classification ofHeadache Disorders (ICHD-2) . (Subjects included in the ICHD -2 appendix are entitiesdeemed to be in need of additional study.) Since the 2004 publication, more than 30 additional
cases have been reported in the English language literature [4-9].Almost a decade after the firstdescription more than 200 NH patients have been reported but population epidemiologic dataare still lacking. In two hospital-based series incidences of 6.4/100.000  and 9/100.000 were estimated. In an outpatient neurologic service NH represented 0.25% of all consultations,and 1.25% of the consultations were because of headache . This article begins with a new case of nummular headache and summarizes the availablecases from the literature. We then review the diagnostic criteria proposed in ICHD-2. Lastly, wepresent the available information on the epidemiology, clinical features, differential diagnosis,and management of this disorder.Case History A 55-year-old man described an 8-month history of focal and well-circumscribed headpain in the left occipital region. The affected area was perfectly circular, measuring 5 cm indiameter. The pain was described as sharp, throbbing, and severe in intensity (8 of 10 on a 10-point anchored scale). The pain was paroxysmal, with attacks lasting from 1 to 10 minutes andoccurring up to six times daily 10 to 12 days per month. The headaches rarely awakened himfrom sleep. Associated features included mild phonophobia, allodynia, and tenderness of theaffected region. Exacerbating factors included high humidity and weather changes, specificallyfrom hot to cold weather. Prior treatment with oxcarbazepine and ibuprofen provided no relief.The patient had a history of depression that was not being treated. Family history revealed thathis mother had migraine. Outside of attacks, inspection and palpation of the cranium demonstrated no alopecia,tenderness, hypoesthesia, allodynia, touch-evoked paresthesias, hyperalgesia, or lesions.During bouts of pain, dysesthesias and allodynia were present within the affected region.Neurologic examination was otherwise normal, and MRI of the brain was also normal.Treatment with nortriptyline, 30 mg nightly, resulted in a reduction in the frequency andintensity of headaches (two headaches per week, graded 1-2 of 10, lasting 1-3 minutes).Diagnostic Criteria The ICHD-2 criteria for nummular headache are provided in Table 1. The criteria requiremild to moderate head pain felt exclusively in a rounded or elliptical area, typically 2 to 6 cm indiameter. In the case presented earlier, and in others from the literature, pain is sometimessevere. The ICHD-2 criteria specify that the pain may be chronic and continuous or interruptedby spontaneous remissions lasting weeks to months. In our case pain was intermittent. Othercauses of focal headache of fixed location must be excluded (see section regarding differential
diagnosis). In our review of the English language medical literature, we identified 60 cases ofnummular headache. Herein, we summarize the available information from these somewhatvariable case reports.Epidemiology, Demographic Features, and Comorbidity Nummular headache is thought to be a rare disorder, but its true prevalence andincidence are uncertain. In one hospital series, the incidence of nummular headache was6.4/100,000/year [2.0]. Nummular headache has a female predominance, with a gender ratio of2.3:1. The age at onset ranges from 13 to 72 years, with a mean age of 41 years. The durationof symptoms before diagnosis ranged from 1 month to 50 years. According to the data on handthe female/male ratio is 1.5:1, and the mean age of onset is 43.6 years (range, 4 –79 years). Theduration of symptoms before diagnosis range from less than 1 month to 50 years .In mostcases there was no specific precipitant identified, although in 7% headache began in closerelation to mild head trauma. Remote head trauma was reported in four patients (9%). A fewpatients (< 7%) may report a possible relationship with a minor head trauma but hardly everreport a link between the trauma site and the area where the pain was experienced [1, 3, 5, 11,14, 20, 23 •• , 33+. One patient related onset of symptoms after an insect bite in the affectedregion [23 •• +. Another patient developed an NH after surgical treatment of a hypophysealadenoma, but in the opposite hemicranium . A history of concurrent headache was found in13 patients (28%). Of the 13 patients, 10 had migraine, two had tension-type headache, onehad trigeminal neuralgia, and one had cervicogenic headache. Comorbid epilepsy or anxietywas documented in 4%. There was no specific information on comorbidities or onset ofconcomitant headache disorders relative to onset of nummular headache.In a recent extensivereview, 55 patients out of 200 (27.5%) reported previous headaches, such as migraine (n = 40),tension-type headache (n = 8), migraine and tension-type headache (n =1), chronic dailyheadache (n =1), orgasmic headache (n =1), primary stabbing headache (n =1), and trigeminalneuralgia (n =1) . Another recently published series of NH found medication overuseheadache in 25% patients .Clinical Features In most cases of nummular headache, the pain was mild to moderate inintensity,although some patients experience severe pain. Fifty percent of the patientsexperienced superimposed exacerbations of pain, lasting from seconds to days.Lancinatingexacerbations, lasting from several seconds to minutes — up to 2 hours, may superimpose thebaseline pain, or may occasionally be the prevailing pain profile *1, 3, 5, 7, 11, 13, 14, 15 •• ,23
•• , 24, 25, 27, 28, 29 •• , 30 – 32] Symptoms presented during daytime in all but a fewpatients, who reported nocturnal pain with frequent or occasional awakenings.The painpredominates during daytime and hardly ever awakens patients from sleep [3, 21, 27]. A fewpatients reported that exacerbations could be precipitated by touching the symptomatic area(9%) or by brushing the hair within the affected region (9%); this may have representedallodynia. A distortion of sensation (paresthesia, hypoesthesia, dysesthesia, or allodynia) wasreported in the region of pain in 46% of patients, as exemplified by our case. In exceptionalcases the pain was precipitated by sexual intercourse (n =1), coughing and Valsalva maneuvers(n =2) , menstruation, or sleep deprivation (n =1) . The quality of the pain was most commonly described as pressure-like, sharp, orstabbing. The attacks were strictly unilateral and without side shift in most of the patients,although some (6%) experienced bilateral pain. The pain was present more often on the rightside (67%) than the left in patients with side-locked attacks. In most instances the headache isstrictly unilateral with the right side being slightly more affected than the left [6, 7].The painwas usually localized to the parietal region (56%) and less often involved the occipital (11%),temporal (19%), or frontal (8%) region; the remaining patients had pain that affected the vertexor two contiguous regions of the head. The site and size of the affected area were typicallydiscrete and fixed within a rounded (75%) or oval/elliptical-shaped (25%) region of the head.The symptomatic area is rounded (3/4) or elliptical (1/4), typically 1 to 6 cm in diameter (range,0.6 – 10 cm) . As a result, the patient could often delineate the outline of the affected regionwith a finger. There is generally a good concordance between patient ’s description andphysician ’ s mapping of the symptomatic area *3].Rarely, the disorder may be bifocal ormultifocal, each symptomatic area keeping all the characteristics of NH [7, 15 •• , 16 • , 17 –19+. Development of multifocal NH may occur with “ consecutive ” (appearance of a new focalarea following the extinction of the previous one), “ additive ” (appearance of a new focal areain addition to the first one), or “ simultaneous ” (synchronous evolution of two focal areas)sequences. The temporal pattern of pain was chronic and continuous since onset (unremitting;57%), chronic 15 days/month but not continuous; 13%), or episodic (< 15 days/month; 30%).Rarely, the chronic course evolves from anepisodic pattern [3, 14, 28].Short-lived periods ofspontaneous remission with return to the previous pattern were observed in one series ofpatients. Associated features were very rare. With the exception of one patient who reportedrhinorrhea specifically with exacerbations of pain, photophobia, phonophobia, nausea,vomiting, or other autonomic features did not accompany the headaches. One patientreported bilateral lacrimation and rhinorrhea during exacerbations , and phonophobia hasbeen described in two patients [21, 35]. Alopecia was noted within the area of pain in onepatientIn addition, a minority of patients may develop trophic changes such as a patch of skin
depression, hair loss, reddish color, and local increased temperature [17, 23 •• +. Skin biopsieswere performed in three patients with trophic changes, and were not specific for any particulardermatologic disease [23 •• +. A 4-year-old child developed an NH in a circumscribed parietalarea with a congenital focal hair heterochromia .Pathogenesis The pathogenesis of nummular headache is uncertain. Some think that the pain stemsfrom a peripheral source, probably from any of the epicranial tissues, including the skull, alllayers of the scalp, vessels, and nerves . We prefer to provisionally consider NH as anepicrania (ie, a headache probably stemming from epicranial tissues, that is, internal andexternal layers of the skull, and all the layers of the scalp, including epicranial nerves andarteries) .Size and shape of the symptomatic area along with signs and symptoms of localsensory dysfunction may suggest neuralgia of a terminal branch of a pericranial nerve.Howevertwo features militate against such a concept: 1) anestheticblock of the symptomaticarea is usually of no avail;and 2) the occasional topography with an elliptical symptomaticareadivided in half by the midline.Early studies designed to determine the extent and distribution ofpain-sensitive structures within the cranium [38, 39] showed that stimulation of the scalp andgalea produced sharply localized pain at the site of the stimulus, whereas stimulation of otherintracranial structures resulted in referred pain in a rather wide area. Recent evidence suggeststhat nummular headache may be associated with a local increase of pain sensitivity tomechanical stimulation within the symptomatic area . Furthermore, pericranial tendernessdoes not seem to be related to nummular headache .It has been demonstrated both inmigraineand tension-type headache that the pain threshold increases in different regions [53–55], whereas in NH it is confined to the symptomatic area [1, 3, 36]. Furthermore, evidence ofincreased mechanical pain sensitivity (lower pressure pain thresholds [PPTs]) restricted to thesymptomatic area in NH has been found .Patients with NH show similar topographicpressure pain sensitivity maps of the head when compared with healthy controls, with localdecrease of PPT levels restricted to the symptomatic zone compared with the nonsymptomaticsymmetrical point (Fig. 1) .NH with trophic changes [23••+ might be considered a restrictedform of complex regionalpain syndrome, which would probably be related to nerveinjury.Theclinical observations do not suggest a psychogenic origin of NH, since the majority of patientswith NH have no previous diagnoses of another psychopathologic disease. Otherwise, it hasbeen documented that NH is not associated with depression and anxiety, since patients withNH showed similar mood states to those of healthy controls [46••+.
Differential Diagnosis and Evaluation A diagnosis of primary nummular headache is made only after alternative causes havebeen excluded. To date, only one report of probable secondary nummular headache has beendescribed in a patient with Marfans syndrome . This patient presented with a 2-monthhistory of focal, circumscribed pain in the right frontal region. An angiogram of the rightexternal carotid artery revealed a fusiform aneurysm. The pain completely resolved aftersurgical resection of the abnormal vessel. However, focal headache may result from a variety ofunderlying causes, including metastatic disease or myeloma of the skull, focal intracranialtumors involving the dura mater (meningiomas), local infection (osteomyelitis), Pagets disease,or inflammatory diseases.Although NH is mostly regarded as a primary disorder, various focalheadaches with a nummular pattern have been related to local lesions of the scalp (fusiformaneurysm of a branch of the superficial temporal artery) , the skull (fibrous dysplasia) ,or the adjacent intracranial structures (meningiomas, arachnoid cysts) [13, 34, 49]. An initial diagnostic work-up should include a complete neurologic examination(including careful inspection and palpation of the scalp and the pericranial muscles, nerves, andarteries), laboratory tests, and neuroimaging studies. Laboratory studies should include acomplete blood count, basic metabolic panel, liver function tests, thyroid function tests,erythrocyte sedimentation rate, alkaline phosphatase, antinuclear antibodies, rheumatoidfactor, angiotensin-converting enzyme, and urine analysis. CT of the head or MRI of the brainshould be performed to exclude any underlying structural abnormality.Management There are no clear guidelines for the management of patients with nummular headache.Initial reports of nummular headache suggested that the low level of pain associated with thedisorder did not necessitate treatment; if required, it was thought to be typically responsive toconventional analgesics. However, contrary to these reports and the current ICHD -2 criteria fornummular headache, patients may experience intense pain and require prophylactic therapy.Treatment with subcutaneous injections of local anesthetics was without benefit. Recently,several agents have been suggested to be partially or completely effective in some case reports,including gabapentin [4,5] and botulinum toxin [7,8]. In such instances gabapentin (300–900 mgdaily) [8, 20, 33] proved to be effective in a substantial number of patients. Alternatively,tricyclic antidepressants rendered satisfactory results in a small seriesof NH patients .Basedon the authors clinical experience with patients who have nummular headache, tricyclicantidepressants such as amitriptyline, nortriptyline, and protriptyline may also beuseful.Botulinum toxin type A has been tried in 24 cases [16•, 26, 29••, 59], with a generally
good response. One series of 14 patients were treated with a dose of 10 U injected in thesymptomatic area resulting in substantial relief to all the patients treated . A short series offour patients with NH resistant to several treatments including NSAIDs, gabapentin, and localanesthetic blocks were treated with botulinum toxin type A, 25 U, injected in several pointsdistributed in both the symptomatic and surrounding areas [29••]. With a latency of 6 to 10days, all the patients improved, the benefit lasting for about 14 weeks. The procedure wassuccessfully repeated. Treatment with transcutaneous electrical nerve stimulation has beenreported as effective .Conclusions Nummular headache is a rare primary headache disorder of unknown etiology. Thediagnosis is one of both inclusion and exclusion. The hallmark of this disorder is a well-circumscribed, focal headache that is usually round or oval in shape. Although usual pain is mildor moderate, severe pain does not exclude the disorder. In patients with nummular headache,the possibility of secondary disorders should be excluded by neurologic examination,neuroimaging, and blood studies. Treatment is often difficult, although neuromodulators,botulinum toxin, and tricyclic antidepressants have been helpful in some patients.
References and Recommended ReadingPapers of particular interest, published recently, have been highlighted as:• Of importance•• Of major importance1.Pareja JA, Caminero AB, Serra J, et al.: Nummular headache: a coin-shaped cephalalgia.Neurology 2002, 58:1678-1679.2.0Pareja JA, Pareja J, Barriga FJ, et al.: Nummular headache: a prospective series of 14 newcases. Headache 2004, 44:611-614. An excellent review of the demographic and clinicalfeatures of nummular headache.3. Headache Classification Subcommittee of the International Headache Society: TheInternational Classification of Headache Disorders 2nd Edition. Cephalalgia 2004, 24(Suppl 1):1-160.4. Evan RW, Pareja JA: Nummular headache. Headache 2005, 45:164-165.5.Trucco M, Mainardi F, Perego G, Zanchin G: Nummular headache: first Italian case andtherapeutic proposal. Cephalalgia 2006, 26:354-356.6. Cohen GL: Nummular headache: what denomination? Headache 2005, 45:1417-1418.7.Dach F, Speciali J, Eckeli A, et al.: Nummular headache: three new cases. Cephalalgia 2006,26:1234-1237.8. Mathew NT, Kailasam J, Meadors L: Nummular headache responds to botulinum toxintype a (BoNTA): experience in four cases. Cephalalgia 2006, 26:1378.9.Seo M, Park S: Botulinum toxin in nummular headache. Cephalalgia 2005, 25:991.10.Pareja JA: Nummular headache: what denomination? A rebuttal. Headache 2005, 45:1418.11. Fernandez-de-las-Penas C, Cuadrado ML, Barriga FJ, Pareja JA: Local decrease ofpressure pain threshold in nummular headache. Headache 2006, 46:1195-1198.12. Fernandez-de-las-Penas C, Cuadrado ML, Barriga FJ, Pareja JA: Pericranial tenderness isnot related to nummular headache. Cephalalgia 2007, 27:182-186.13. Garcia-Pastor A, Guillem-Mesado A, Salinero-PaniaguaJ, Gimenez-Roldan S: Fusiformaneurysm of the scalp: an unusual cause of focal headache in Marfan syndrome. Headache2002, 42:908-910.
Table 1. 2004 International Headache Society criteria for the diagnosis of nummularheadacheA. Mild to moderate head pain fulfilling criteria B and CB. Pain is felt exclusively in a rounded or elliptical area typically 2-6 cm in diameterC. Pain is chronic and either continuous or interrupted by spontaneous remissions lasting weeks to months D. Not attributed to another disorder(Data from Headache Classification Subcommittee of the International Headache Society.)