Key Points
• Source: Journal of Occupational Health
• Conclusion/Relevance: “We showed that MCS [multiple chemical sensitivity] was observed in 20% of patients with migraine, and our study results may indicate a possible association of MCS with central sensitization and hypersensitivity-related symptoms in patients with migraine.”
• In the current cross-sectional study, Japanese investigators included 95 patients. No patients were previously diagnosed with MCS. The MCS-positive cohort exhibited increased photophobia, osmophobia, visual/sensory aura, and central censitization, with sensory aura, osmophobia, and central sensitization playing a role in MCS.
• “Cortical hyperexcitability may increase the probability of the development of cortical spreading depression, which has been implicated in migraine auras, whereas the increased excitability of trigeminal neurons may facilitate peripheral and central sensitization,” the authors wrote. “In migraineurs, altered functional connectivity between brainstem pain-modulating circuits and the limbic cortex, including the amygdala, which facilitates pain perception through the sensory cortex and plays a role in fear conditioning and stress responsiveness, has been described. Patients with MCS showed significantly higher metabolism in the bilateral olfactory cortices than healthy controls during the resting state.”
• Limitations of the current study include its small sample size, the inability to determine the relationship between MCS and headache onset, and a paucity of healthy controls.