Abstract
Background: Although cranial autonomic symptoms are typical in cluster headache, some individuals with cluster headache show no cranial autonomic symptoms during their headache attacks. Probable cluster headache is a subtype of cluster headache that fulfils all but one of the five criteria for cluster headache. This study aimed to investigate the frequency and clinical features of cluster headache and probable cluster headache without cranial autonomic symptoms in comparison to those with cranial autonomic symptoms.Methods: We analysed data from the Korea Cluster Headache Registry, a prospective multicentre registry involving data from 16 hospitals.Results: Of the 216 participants with cluster headache and 26 with probable cluster headache, 19 (8.8%) and 7 (26.9%), respectively, did not have cranial autonomic symptoms. Participants with cluster headache without cranial autonomic symptoms exhibited less severe anxiety (General Anxiety Disorder-7 score, median [interquartile range], 2.0 [1.0-6.0] vs 8.0 [3.0-12.0], p = 0.001) and depression (Patient Health Questionnaire-9 score, 3.0 [1.0-7.0] vs 7.0 [3.0-11.0], p = 0.042) than those with cranial autonomic symptoms. Other clinical features, including headache intensity, daily headache frequency, attack duration, bout duration, and location of the pain, did not differ between participants with cluster headache with and without cranial autonomic symptoms. Headache intensity was less severe in participants with probable cluster headache without cranial autonomic symptoms than in those with cranial autonomic symptoms (numeric rating scale, 8.0 [7.0-8.0] vs 9.5 [8.0-10.0], p = 0.015).Conclusions: A significant proportion of participants with cluster headache and probable cluster headache did not have cranial autonomic symptoms. Some clinical features of cluster headache and probable cluster headache differed based on the presence of cranial autonomic symptoms.