Nummular headache: an update and future prospects.

INTRODUCTION: Nummular headache (NH) is characterized by continuous or intermittent head pain, which remains confined to a round or oval shaped area of the scalp, generally 1 to 6 cm in diameter. Usually mild or moderate in intensity, some patients suffer severe acute exacerbations or continuous disabling pain. Areas covered: This article reviews epidemiological and clinical features of NH, the most recently proposed pathophysiological mechanisms, and state-of-the-art management according to the literature. Expert commentary: Information regarding true incidence and prevalence is lacking, but NH is a fairly common disorder in patients attending a headache clinic. Diagnostic work-up requires the exclusion of systemic and structural disease by a thorough physical examination, blood tests including immunology screening, and neuroimaging. No clinical trials have been conducted for NH, so the level of evidence for any treatment is low. Gabapentin seems to be the most effective oral medication; subcutaneous injection of the area with onabotulinum toxin type A also seems to be effective, and should be considered as an alternative to gabapentin.