Primary stabbing headache in a tertiary headache centre.

INTRODUCTION: Primary stabbing headache (PSH) is a short-lasting head pain occurring spontaneously in the absence of underlying structural causes. Although it is a frequent disorder, with a reported lifetime prevalence of 35.2% in the general population, its pathophysiological underpinnings remain incompletely understood. Notably, PSH frequently coexists with other primary headache disorders, particularly migraine, suggesting a possible shared biology. METHODS: We retrospectively reviewed the medical records as a service evaluation of all patients diagnosed with PSH, using the International Classification of Headache Disorders, third edition, in our clinic between 2018 and 2025 as a service evaluation. Data on demographic variables and the presence of other primary headache disorders were collected and analysed. Concurrently, we conducted a systematic literature search according to PRISMA guidelines. A comprehensive search of PubMed/MEDLINE and EMBASE via Scopus through April 2025 identified studies examining the relationship between PSH and other primary headache disorders. RESULTS: The retrospective analysis identified 68 patients who met the strict diagnostic criteria for PSH. Notably, 90% of these individuals were found to have a concomitant migraine diagnosis, while hemicrania continua (HC) and cluster headache (CH) were reported in 7% and 10% of cases, respectively. From the literature search, 27 eligible studies were included. Overall, a significant rate of co-occurrence between PSH and migraine was consistently reported, sometimes exceeding two-thirds of PSH cases. Likewise, in migraine cohorts PSH has been repeatedly observed at substantial rates, suggesting a close link between the two conditions. PSH was commonly reported within trigeminal autonomic cephalalgias (TACs), occurring in 36-41% of HC cases and in 2-33% of CH series. In contrast, when PSH itself is the index disorder, accompanying TACs were infrequent, appearing in only 0-8% of PSH cases. DISCUSSION: Based on both our clinical observations and the published data, PSH and migraine appear closely intertwined. Although the precise mechanisms remain speculative, the high degree of comorbidity underscores the possibility that PSH and migraine share overlapping pathophysiological pathways. Our findings lend support to the hypothesis that PSH may be facilitated by an underlying migraine biology. Clinically, our data may be an under-estimate as stabbing headache is generally not the presenting issue and may not have been well recorded. Future research aimed at elucidating molecular mechanisms could further clarify the nature of this relationship and pave the way for targeted therapies.