Characteristics and treatment effectiveness of the nummular headache: a systematic review and analysis of 110 cases.

[BACKGROUND/OBJECTIVE] Nummular headache (NH) is a primary headache disorder characterised by intermittent or continuous scalp pain, affecting a small circumscribed area of the scalp. As there are limited data in the literature on NH, we conducted this review to evaluate demographic characteristics and factors associated with complete resolution of the headache, and effectiveness of treatment options.

[METHODS] We performed a systematic review of cases reported through PubMed database, using Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol and 'nummular headache', 'coin-shaped headache' and 'coin-shaped cephalalgia' keywords. Analysis was performed by using χ test and Wilcoxon rank-sum test. For individual interventions, the response rate (RR%) of the treatment was calculated.

[RESULTS] We analysed a total of 110 NH cases, with median age 47 years and age of pain onset 42 years. Median duration to make correct diagnosis was 18 months after first attack. The median intensity of each attack was 5/10 on verbal rating scale over 4 cm diameter with duration of attack <30 min. Patients with NH had median three attacks per day with frequency of 9.5 days per month. 40 (57.97%) patients had complete resolution of the headache after treatment. Patients with complete resolution were younger, more likely to be female, and were more likely to have diagnosis within year. Patients with complete resolution more likely to have received treatment with onabotulinum toxin A (botulinum toxin type A (BoNT-A)), and gabapentin compared with patients without complete resolution. Most effective interventions were gabapentin (n=34; RR=67.7%), non-steroidal anti-inflammatory drugs (NSAIDs) (n=32; RR=65.6%), BoNT-A (n=12; RR=100%) and tricyclic antidepressant (n=9; RR=44.4%).

[CONCLUSION] Younger patients, female sex and early diagnosis were associated with complete resolution. NSAIDs, gabapentin and BoNT-A were most commonly used medications, with significant RRs.