Dehydration and Headache

Dehydration is a common but often overlooked cause of headaches, affecting both primary and secondary headache disorders. While the International Classification of Headache Disorders (ICHD-3) does not specifically recognize a dehydration-related headache syndrome, the connection between fluid loss and headache is well-established. This review delves into the physiological mechanisms behind dehydration-induced headaches and explores their impact on various headache disorders.

Dehydration can exacerbate primary headaches, such as migraines, by lowering the threshold for pain and triggering migraine attacks. Studies have shown that inadequate hydration can increase the frequency, severity, and duration of headaches, especially in individuals prone to migraines. Additionally, dehydration plays a significant role in secondary headaches, often complicating conditions like cerebral venous sinus thrombosis, post-lumbar puncture headache, and headaches related to orthostatic hypotension.

The underlying mechanisms are multifaceted, involving changes in blood volume, electrolyte imbalances, and the stretching of pain-sensitive structures in the brain. Furthermore, dehydration may aggravate autonomic disorders like postural orthostatic tachycardia syndrome (POTS), leading to orthostatic headaches that worsen with upright posture.

Treatment for dehydration-related headaches primarily focuses on rehydration, though the approach may vary depending on the specific headache disorder. For those with migraines, maintaining adequate fluid intake is crucial for prevention, while for others, addressing the underlying cause of dehydration is key. This review underscores the importance of hydration in managing headaches and highlights the need for further research to better understand the relationship between hydration status and headache disorders.