Why Migraines Cause Sweating
Sweating during migraine attacks occurs due to autonomic nervous system dysfunction and parasympathetic activation, particularly involving the trigeminovascular pathway and reflex mechanisms that are part of the migraine pathophysiology itself. 1, 2
Autonomic Nervous System Involvement
The sweating associated with migraine is a manifestation of autonomic dysfunction that accompanies the attack rather than a direct consequence of reduced cerebral blood flow. 1
- Sweating occurs as a symptom related to the mechanism causing the migraine attack itself, not from decreased cerebral blood flow. 1
- These autonomic symptoms (including sweating and nausea) occur close in time to the migraine attack and are indirectly linked to the loss of normal neurological function. 1
- Research demonstrates that sweating function is actually impaired in migraine patients during headache-free intervals, with classic migraine patients showing significantly lower sweat gland responses compared to controls. 3
Parasympathetic Activation During Attacks
The sweating mechanism involves parasympathetic nervous system activation during migraine attacks:
- Parasympathetic outflow increases during migraine attacks, which can trigger sweating through lacrimotor fibers that may branch into sudomotor (sweat-producing) pathways. 4
- This explains why excessive forehead sweating can occur during attacks, particularly in cluster headache (a related trigeminal autonomic cephalalgia), even when sympathetic dysfunction is present. 4
Neurobiological Basis
Migraine is fundamentally a disorder of increased CNS excitability affecting multiple neuronal systems:
- The migraine brain exhibits generalized neuronal hyperexcitability and structural/functional abnormalities that affect autonomic regulation. 5
- Multiple neuronal systems function abnormally from the prodromal stage through the headache phase, including those controlling autonomic functions like sweating. 5
- The disease involves abnormal sensitivity to fluctuations in homeostasis and decreased adaptive capacity, which manifests as autonomic symptoms including sweating. 5
Clinical Recognition
Sweating should be recognized as part of the broader autonomic symptom complex in migraine:
- Sweating typically occurs alongside other autonomic symptoms such as nausea, which are characteristic features of reflex syncope-like mechanisms in migraine. 1
- The presence of sweating, particularly when accompanied by nausea and other typical migraine features (photophobia, phonophobia), supports the diagnosis of migraine. 1, 2
Clinical Pitfall
Do not confuse migraine-associated sweating with hyperventilation or panic attacks, as hyperventilation itself is not certain to cause loss of consciousness and falls under different diagnostic categories in psychiatric classification systems. 1