Abstract
I read with extreme interest the paper by Moon et al. (1) This study is one of the largest case series on nummular headache (NH). In this study, no patient had more than one area of pain.
In fact, more than one area of pain in the same patient seems to be an uncommon characteristic of this headache. We report a case of NH with two areas of pain.
A 52-year-old man came to our observation with four years of continuous pain in two circumscribed head areas simultaneously. The painful areas were located on the same side of the head, in the right parietal region. Both were round, were 2 cm in diameter and were separated by a 3-cm pain-free area. The pain was continuous, throbbing and mild, with four to six daily exacerbations lasting less than a minute and characterized by a stabbing, severe pain. The exacerbation of one area of pain occurred one minute after the other, and began without any precipitant. The pain was not associated with nausea, vomiting, photophobia or phonophobia, nor was it aggravated by routine physical activity.
The patient had presented with migraine without aura for 30 years, with four attacks of headache per year, in the bilateral frontal region. There was no history of head trauma.
Neurological examination was completely normal. There was no hypo-esthesia, paresthesia, dysesthesia, allodynia, tenderness or trophy changes within the symptomatic area. The patient underwent MRI scan of the brain, which proved normal. A therapeutic trial with local subcutaneous lidocaine application in painful areas provided complete pain relief.
Since the first description of NH in 2002, more than 100 cases have been reported. As far as we know, just four cases had more than one site of pain: (i) two sites of pain occurring on different sides of the head (no information about the temporal relationship between the sites) (2); (ii) two sites of pain occurring on different sides of the head in different periods; (iii) two sites of pain occurring on the same side of the head, but with one site starting to be painful before the other; and (iv) two sites of pain occurring on different sides of the head simultaneously (3). Our patient was the first reported to have pain in two different sites on the same side of the head simultaneously.
The exact etiology of NH is not clear. Possible mechanisms proposed are a neuropathy of a terminal branch of a cutaneous scalp nerve and a focal, nociceptive-type pain stemming from epicranial tissues (4–6). The good response with lidocaine suggests a peripheral source of the pain in our patient. Local subcutaneous lidocaine application failed to reduce NH pain in other patients (4,7–9). The existence of bifocal or multifocal NH may indicate that the local processes of NH can be reproduced in multiple cranial areas (3).