Objective: To study the clinical features of nummular headache (NH) and get an approach to its epidemiology.
Background: NH has been recently described as a primary disorder characterized by head pain exclusively felt in a small rounded area typically 2-6 cm in diameter.
Methods: Through a 1-year period we have studied all patients referred to our neurologic clinic because of head pain exclusively felt in a small-circumscribed area, and not attributed to another disorder. All the patients had normal neurological, analytical, and neuroimaging examinations. All the patients belonged within the same regional care system comprising 220,000 inhabitants.
Results: A total of 11 females and 3 males were studied. Based in our hospital series, the incidence was 6.4/100,000/year. The mean age at the onset was 38 years (range: 13-72). Only three patients had another concurrent headache: migraine (n = 2), and trigeminal neuralgia (n = 1) which proved to have an independent course. All the patients reported head pain exclusively felt in either a rounded (n = 12) of 1-6 cm diameter, or an oval area (n = 2) of 5 x 3 cm, and 2 x 3 cm, respectively. Both size and shape of the painful area remained constant since the onset of symptoms. The location of the symptomatic area was mostly parietal (n = 7) or temporal (n = 5), but also frontal (n = 1) and in occiput (n = 1). The background pain was mostly mild-to-moderate, but also moderate-to-severe pain was reported. Exacerbations-either spontaneous or precipitated by combing hair or touching the symptomatic area-were reported by 8 patients. The temporal pattern was chronic-continuous (n = 7) and episodic (n = 7). Ten patients reported a variable combination of sensory disturbance (tenderness, hypoesthesia, hyperalgesia, and allodynia) in the symptomatic area. There were no autonomic accompaniments. Treatment was generally not necessary. When needed, standard oral doses of paracetamol usually sufficed.
Conclusions: NH emerges as a clear-cut clinical picture. It is a noninfrequent primary headache. The particular topography suggests the pain has a probable epicranial source conveyed by, or originated in, one/a few terminal branch(es) of the cutaneous nerves of the scalp.