Epidemiology and clinical features of short-lasting unilateral neuralgiform headache attacks: A systematic review and meta-analysis.

Background: To synthesize the available epidemiologic data on short-lasting unilateral neuralgiform headache attacks (SUNHA). This, in turn, might inform diagnostic work-up and clinical decision-making.

Methods: EMBASE and PubMed were searched for observational studies reporting on the prevalence or relative frequency of SUNHA or its individual clinical features. Two investigators independently conducted title and abstract screening, full-text review, data extraction, and risk of bias assessment, and random-effects meta-analyses were performed to estimate the prevalence or relative frequency of SUNHA and its individual clinical features.

Results: Fifteen clinic-based studies met our eligibility criteria. Of these, five studies reported estimates on the relative frequency of SUNHA among adults evaluated for headache or facial pain, yielding a pooled relative frequency as 0.32% (95% confidence interval = 0.17-0.62; I²= 89.9%). Most often, SUNHA presented as episodic, side-locked stabbing headache of severe pain intensity, predominantly affecting the ophthalmic and/or maxillary branch of the trigeminal nerve. The most common cranial autonomic features were lacrimation, conjunctival injection, rhinorrhea and nasal congestion.

Conclusions: SUNHA is a rare headache disorder with distinct clinical features. However, our findings must be interpreted with caution as a result of between-study heterogeneity and lack of population-based studies, underscoring the need for further epidemiologic research.