Epicranial headache part 1: Primary stabbing headache.

BACKGROUND/OBJECTIVE: Primary stabbing headache is a common but under-recognized primary headache disorder. The objectives of this review were to provide practical information for better understanding and identification of the disease, suggest an algorithm for differential diagnosis, and provide an insight into the pathophysiology of primary stabbing headache hypothesized from its clinical course. METHODS: This narrative review of primary stabbing headache is based on a literature search and the authors' clinical reasoning. RESULT: The phenotype of each stab is typically abrupt, ultrashort-lasting (<3 s), focal or multifocal, paroxysms of pain occurring sporadically or in clusters. The diagnosis of primary stabbing headache is clinical; fixed or migrating stabs without background pain or sensory abnormalities and the absence of features suggestive of other disorders (e.g., cranial autonomic symptoms or signs) can aid in the diagnosis of primary stabbing headache. The clinical patterns include monophasic, intermittent, and chronic primary stabbing headache, of which the first two are considered typical. The pathophysiology of primary stabbing headache has not yet been elucidated. In this review, we postulated the mechanism of stabbing headache, based on the pain phenotype and clinical course, and provide a clinical algorithm for the differential diagnosis of primary stabbing headache. CONCLUSION: Knowledge about the typical manifestations and clinical patterns of primary stabbing headache will aid in the proper diagnosis and differential diagnosis. Treatment should be tailored by considering the clinical patterns. Further research is needed to elucidate the pathophysiological mechanisms and optimal treatment of primary stabbing headache.