Skin wetness sensitivity across body sites commonly affected by pain in people with migraine

Objective: The objective of this study was to evaluate skin wetness perception and thermal sensitivity in people with migraine and similar healthy controls.Background: Environmental triggers, such as cold and humidity, are known triggers for pain in people with migraine. Sensory inputs might be implicated in such heightened responses to cold-humid environments, such that a migraine-induced hypersensitivity to cold wetness could be present in people with migraine. However, we lack empirical evidence on skin thermal and wetness sensitivity across skin sites commonly associated with reported pain in migraine, such as the forehead.Methods: This prospective cross-sectional observational study, conducted in a university hospital setting, evaluated skin wetness perceptions and thermal sensations to wet non-noxious warm-wet, neutral-wet, and cold-wet stimuli applied to the forehead, the posterior neck, and the index finger pad of 12 patients with migraine (mean and standard deviation for age 44.5 +/- 13.2 years, 7/12 [58%] women) and 36 healthy controls (mean and standard deviation for age 39.4 +/- 14.6 years, 18/36 [50%] women).Results: On the forehead, people with migraine reported a significantly higher wetness perception than healthy controls across all thermal stimulus (15.1 mm, 95% confidence interval [CI]: 1.8 to 28.5, p = 0.027, corresponding to similar to 15% difference), whereas no significant differences were found on the posterior neck nor on the index finger pad. We found no differences among groups in overall thermal sensations (-8.3 mm, 95% CI: -24.0 to 7.3, p = 0.291; -7.8 mm, 95% CI: -25.3 to 9.7, p = 0.375; and 12.4 mm, 95% CI: -4.0 to 28.9, p = 0.133; forehead, posterior neck, and index finger, respectively).Conclusion: These findings indicate that people with migraine have a heightened sensitivity to skin wetness on the forehead area only, which is where pain attacks occur. Future studies should further explore the underlying mechanisms (e.g., TRPM8-mediated cold-wet allodynia) that lead to greater perception of wetness in people with migraine to better understand the role of environmental triggers in migraine.