Bifocal nummular headache: the first three cases.

Nummular headache (NH) has been defined as a focal head pain that is exclusively felt in a small area of the head surface. Here we describe three patients who presented with focal head pain in two separate areas. This finding seems to be consistent with bifocal NH and further enlarges the clinical diversity of this headache disorder. The pathogenic mechanisms of NH may be active in multiple cranial areas in some particular patients.