7. Swelling in the eyelids
Another symptom mediated by histamines is an abnormal and temporary swelling or edema in the eyelids. Similar to what we have already described in the nasal cavity, in a very specific type of migraine headaches, we have an abnormal discharge of histamines that affects the blood vessels in the eyes and eyelids. This leads to the dilation of the blood vessels, filtration of liquids out of the blood vessels in the eyelids and collection of water in the interstitial tissue.
This symptom is called palpebral edema, and it is an alarm sign in cases of food allergies and other types of allergic reactions. Thus, it is very important to talk to your doctor if you have this and any other concerning symptoms to be able to differentiate one medical condition with other life-threatening problems that may arise in the same patient.