Cluster Headache and COVID-19, a Retrospective Study on Disease Evolution during the Pandemic

Background: Cluster headache (CH) is a recurrent disease, characterized by severe intensity periorbital headache associated with ipsilateral autonomic signs and symptoms; attacks may occur several times per day, for periods of weeks (so-called cluster), with a relapsing periodic pattern during the year. COVID-19 pandemic has induced many lifestyle changes on the general population, especially related to the so-called lockdown. Aim of this study was to assess the clinical evolution of cluster headache patients during the lockdown period. Methods: Patients included in this observational retrospective study had a definite diagnosis of cluster headache, with a minimum 5-year disease duration. Main collected data included diagnosis, age, disease duration, number of clusters per year, cluster duration, number of attacks per day and attack duration (both pre and post pandemic onset). Statistical analysis was performed to assess differences in cluster headache clinical manifestations before and after pandemic onset. Results: The study included 44 patients, with mean age of 48.8 ± 12.6 years and male prevalence (35 male patients (79%)). Mean disease duration was 16.9 ± 8.5 years. Episodic CH was prevalent, with 40 patients with diagnosis of episodic CH (91%) and only 4 patients with diagnosis of chronic CH (9%). Comparing pre-pandemic period and lockdown period, mean cluster number per year was 1.6 ± 0.9 vs 0.7 ± 1.2 (p = 0.001), mean cluster duration was 70.6 ± 98.4 days vs 24.4 ± 61.4 days (p = 0.001), mean headache attacks per day were 2.8 ± 1.2 vs 0.8 ± 1.0 (p ＜ 0.001), mean headache attack duration was 47.1 ± 31.0 minutes vs 15.3 ± 20.9 minutes (p ＜ 0.001). Pain intensity measured using the Numerical Rating Scale was 10 for all patients vs 4.3 ± 5.0 (p ＜ 0.001). Conclusion: The results of this study showed a significant reduction in disease severity for cluster headache patients comparing the prepandemic and the lockdown period; this finding may be partly due to the lifestyle changes occurring as a consequence of the lockdown restrictive measures (with subsequent changes in circadian rhythm, sleep-wake cycle and hypothalamic function), even though the observed results were normalized considering the single-patient specific lifestyle and job activity performed during the lockdown, further underlining the peculiarity of this phenomenon.