The analysis of allodynia in patients with idiopathic intracranial hypertension

Abstract

Allodynia is frequently associated with migraine and other primary headaches. Our aim was to investigate the presence of allodynia and related features in idiopathic intracranial hypertension (IIH), which is a disabling secondary headache disorder. We included 46 IIH patients and analyzed their clinical and laboratory findings retrospectively. Allodynia was assessed using the validated 12-item allodynia symptom checklist (ASC-12), in addition to examining pressure (with von Frey filaments) and brush allodynia. Allodynia was detected in 23 (50%) of IIH patients with ASC-12 and/or instrumental testing. The most commonly reported location was unilateral V1 distribution. The allodynic symptom profile was similar but milder when compared to 143 migraineurs with ASC-12. Only the aggravation of headache with physical activity emerged as a significant variable associated with allodynia in IIH. Among allodynic patients, only eight had previous migraine diagnosis. After onset of IIH, 20 patients reported migraine-like headache, while only three reported non-migrainous headache. In contrast, 13 of 23 non-allodynic IIH patients had non-migrainous headache features (p = 0.0045). Half of the IIH patients reported allodynia, and these allodynic patients had mostly migraine-like headache profiles. Our study suggested that IIH may trigger some common mechanisms with migraine in pain pathways causing allodynia.