A new variant nummular headache: large diameter accompanied with bitrigeminal hyperalgesia and successful treatment with carbamazepine.

Nummular headache (NH) is defined as a focal head pain that is exclusively felt in a small area, which is typically 1-6 cm in diameter. Neurological examinations are normal in all patients, but this report describes a new variant. A patient was identified who presented with focal head pain that was approximately 8 cm in diameter and bitrigeminal hyperalgesia on neurological examination. Treatment with carbamazepine provided significant analgesic relief in terms of both the frequency and intensity of pain. The findings enlarge the clinical diversity of this headache disorder. The pathogenic mechanisms of NH may be similar to trigeminal neuralgia in particular patients.