6. Nasal discharge and nasal congestion
The eyes and the nasal cavities are connected through a series of tubules that drain tears into the nose, which is why crying is always followed by nasal discharge. Similarly, excessive tearing leads to nasal discharge in the side affected by the headache symptoms. Such a discharge is usually crystal clear because it is formed mainly by tears.
Moreover, certain types of migraines trigger an inflammatory reaction mediated by histamines, a substance that is commonly involved in allergies and respiratory infections. Histamines in the blood vessels of the nasal cavity mediates vasodilation of the blood vessels, leads to fluid loss by osmosis and activates the cells that produce mucus. Thus, many patients do not only experience an annoying nasal discharge but nasal congestion as well.