Nummular headache is a type of headache that can be identified by continuous or intermittent pain occuring in a well-circumscribed area. The symptoms of nummular headache can overlap with those of migraine headache, and a failure to reach an accurate diagnosis can affect the choice of treatment. The authors report a case involving a 21-year-old woman with headache symptoms that appeared to represent nummular headache, for whom treatment with the typical first-line agent was unsuccessful. The authors subsequently generated a pressure algometry map of the painful area, leading to clarification of the diagnosis.