Nummular headache is an uncommon chronic headache syndrome characterized by constant localized pain with superimposed paroxysms of stabbing jabs and jolts of mild to moderate intensity that occur in a coin-shaped localized area of the scalp.
Most commonly located in the parietal region, the pain of nummular headache is unilateral and localized to a single area. It rarely if ever switches sides. The scalp overlying the area may be tender to touch and stimulation of the area; for example, the brushing of hair may exacerbate the pain.
Nummular headache occurs slightly more commonly in women and is generally not seen before the fourth decade of life, but rare reports of children suffering from nummular headache sporadically appear in the literature. Nummular headache has been associated with coexistent migraine headache and occipital neuralgia.
A high prevalence of autoimmune indices and disorders have also been identified in patients suffering from nummular headache. Nummular headache is also known as coin-shaped headache.
What are the Symptoms
A patient with nummular headache complains of a unifocal region of pain and sensitivity most commonly occurring in the vertex of the parietal region. The pain is almost always unilateral and does not switch sides, although rare reports exist of bilateral nummular headache.
Some patients describe the pain of nummular headache as a constant dull ache or sensitivity in the affected area with superimposed paroxysms of lancinating pain. The pain is chronic, although spontaneous remissions have been rarely reported. Some patients with nummular headache exhibit anxiety and depression because the intensity of the associated pain leads many patients to believe they have a brain tumor.
How is Nummular Headache diagnosed?
Magnetic resonance imaging (MRI) of the brain provides the best information regarding the cranial vault and its contents. MRI is highly accurate and helps identify abnormalities that may put the patient at risk for neurological disasters secondary to intracranial and brainstem pathological conditions, including tumors and calvarial lesions.
Magnetic resonance angiography (MRA) also may be useful in helping identify aneurysms, which may be responsible for the patient’s pain. In patients who cannot undergo MRI, such as patients with pacemakers, computed tomography (CT) is a reasonable second choice. Radionuclide bone scanning and plain radiography are indicated if fracture or bony abnormality, such as metastatic disease, is considered in the differential diagnosis.
Screening laboratory tests consisting of complete blood cell count, erythrocyte sedimentation rate, and automated blood chemistry should be performed if the diagnosis of nummular headache is in question.
Nummular headache is a clinical diagnosis supported by a combination of clinical history, normal physical examination, radiography, and MRI. Pain syndromes that may mimic nummular headache include chronic paroxysmal hemicrania and jolts and jabs headache.
Trigeminal neuralgia involving the first division of the trigeminal nerve is uncommon and is characterized by trigger areas and tic-like movements. Demyelinating disease is generally associated with other neurological findings, including optic neuritis and other motor and sensory abnormalities.
The pain of chronic paroxysmal hemicrania lasts much longer than the pain of nummular headache and is associated with redness and watering of the ipsilateral eye.
Nummular headache uniformly responds to treatment with indomethacin. Failure to respond to indomethacin puts the diagnosis of nummular headache in question. A starting dosage of 25 mg daily for 2 days and titrating to 25 mg three times a day is a reasonable treatment approach. This dose may be carefully increased to 150 mg/day.
Indomethacin must be used carefully, if at all, in patients with peptic ulcer disease or impaired renal function. Anecdotal reports of a positive response to cyclooxygenase-2 (COX-2) inhibitors in the treatment of nummular headache have been noted in the headache literature, as well as a successful treatment with gabapentin.
Underlying sleep disturbance and depression are best treated with a tricyclic antidepressant compound, such as nortriptyline, which can be started at a single bedtime dose of 25 mg.
Failure to diagnose nummular headache correctly may put the patient at risk if an intracranial pathological condition or calvarial disease, which may mimic the clinical presentation of nummular headache, is overlooked.
MRI is indicated in all patients thought to have nummular headache.
The diagnosis of nummular headache is made by taking a careful, targeted headache history. Patients with nummular headache should have a normal neurological examination.
If the results of the neurological examination are abnormal, the diagnosis of nummular headache should be discarded and a careful search for the cause of the patient’s neurological findings should be undertaken.