BackgroundAccording to the International Classification of Headache Disorders diagnostic criteria, the differences between migraine and cluster headache (CH) are clear. In addition to headache attack duration and pain characteristics, the symptoms accompanying headache represent the key features in a differential diagnosis of these 2 primary headache disorders. Just a few studies of patients with CH exist examining the presence of nausea, vomiting, photophobia, phonophobia, and aura, the features commonly accompanying migraine headache. The aim of this study was to determine the presence of migraine-like features (MF) in patients with CH and establish the significance of these phenomena related to other clinical features and response to treatment. MethodsOne hundred and fifty-five patients with CH were studied, and 24.5% of them experienced at least one of MF during every CH attack. Nausea and vomiting were the most frequently reported MF. The clinical presentation between CH patients with and without MF was not significantly different with the exception of aggravation of pain by effort (20.6% vs 4.1%) and facial sweating (13.2% vs 0.85%), both more frequent in CH patients with MF. ConclusionInferred from the results of our study, the presence of MF in CH patients had no important influence on the diagnosis and treatment of CH patients. The major differences of these 2 primary headache disorders, attack duration, lateralization, and the nature of associated symptoms, as delineated in the International Classification of Headache Disorders, are still useful tools for effective diagnosis.