Migraine Headache Triggered Specifically by Sunlight: Report of 16 Cases

Certain headaches arise from intracranial pathologies, like meningitis or tumors. These headaches result from mechanical or chemical stimulation of sensitive structures. Migraines, however, have an unknown origin and lack identifiable pathology. They share features with intracranial headaches, indicating heightened sensitivity to intracranial pressure changes. This sensitivity worsens with actions like coughing or sudden head movement. Researchers suggest that meningeal afferents may become sensitized to mechanical stimuli, causing migraine symptoms. Past studies focused on the central trigeminal pathway, overlooking potential sensitization. This research examined the activity of primary afferent neurons in rat trigeminal ganglia. These neurons innervate dural venous sinuses and respond to chemical stimulation. Inflammatory mediators excited these neurons and increased their sensitivity to mechanical stimuli. This enhanced sensitivity may explain the mechanical hypersensitivity linked to certain headaches, like migraine, which often presents as throbbing pain. Clinical relevance: This research indicates that sensitization of meningeal afferents may worsen migraine symptoms.