Are there differences between patients with unifocal nummular headache and those who progress to bifocal nummular headache? A retrospective observational study.

Objectives: This retrospective observational cohort study aimed to compare clinical characteristics and treatment responses in patients exclusively experiencing unifocal nummular headache (NH) with those who develop the bifocal variant.

Methods: A retrospective study was conducted on patients diagnosed with NH who attended a neurology (headache) outpatient clinic between January 2018 and December 2022. The cohort was divided into two groups: Group 1, exclusive unifocal NH; and Group 2, those developing a secondary focal area of pain, i.e., bifocal NH. Data were collected on demographic characteristics, clinical features, other headache comorbidities, and treatment-related information.

Results: A total of 23 patients were included in this study: 12 were categorized as unifocal NH (Group 1) and 11 as bifocal NH (Group 2). There were no differences between the two groups in terms of demographic characteristics, clinical features, or treatment response. Nonetheless, patients with bifocal NH exhibited spontaneous remission rates in the first pain area when compared to the unifocal NH group, with statistically significant differences (36% vs. 0%, p = 0.020).

Conclusion: In our sample, patients with bifocal NH demonstrated spontaneous remission rates in the initial pain area, a phenomenon not observed in patients with unifocal NH. It is worth noting the limited sample size in the present study, highlighting the need for larger cohorts to validate and further explore our findings.