REPRINTED WITH PERMISSION OF IASP - Allodynia in cluster headache

Cutaneous allodynia is an established marker for central sensitization in migraine. There is debate whether cutaneous allodynia may also occur in cluster headache, another episodic headache disorder. Here, we examined the presence and severity of allodynia in a large well-defined nationwide population of people with cluster headache. Using validated questionnaires we assessed, crosssectionally, ictal allodynia and comorbid depression and migraine in the nationwide “Leiden University Cluster headache neuro-Analysis” (LUCA) study. Participants with cluster headache were diagnosed according to the International Classification of Headache Disorders criteria. Multivariate regression models were used, with correction for demographic factors and cluster headache subtype (chronic vs episodic; recent attacks ,1 month vs no recent attacks). In total, 606/798 (75.9%) participants with cluster headache responded; of whom, 218/606 (36%) had allodynia during attacks. Female gender (odds ratio [OR] 2.05, 95% confidence interval [95% CI] 1.28-3.29), low age at onset (OR 0.98, 95% CI 0.96-0.99), lifetime depression (OR 1.63, 95% CI 1.06-2.50), comorbid migraine (OR 1.96, 95% CI 1.02-3.79), and having recent attacks (OR 1.80, 95% CI 1.13-2.86), but not duration of attacks and chronic cluster headache, were independent risk factors for allodynia. The high prevalence of cutaneous allodynia with similar risk factors for allodynia as found for migraine suggests that central sensitization, like in migraine, also occurs in cluster headache. In clinical practice, awareness that people with cluster headache may suffer from allodynia can in the future be an important feature in treatment options.