Can caffeine cause facial and tongue numbness?
I also drink wine in the evening to help me sleep or with dinner, but not every night.
They could influence it, yes.
I read your question carefully and I understand your concern.
It is a good thing you have had MRI and other tests which have excluded any serious condition. Regarding whether drinking little water and having many caffeinated drinks can exacerbate your symptoms the answer is yes, they can certainly be a factor, especially the many caffeinated drinks.
There are no direct studies specifically for tongue numbness, but there is certainly evidence regarding caffeine and anxiety. Caffeine stimulates metabolism and increases levels of stress hormones. That can lead to anxiety which in turn can have many manifestations including abnormal sensations in the limbs or in the tongue and face such as in your case.
That doesn't necessarily mean too much coffee and little water are the only factors, anxiety is a very common issue which might be present even in their absence, but they certainly can contribute and exacerbate the intensity and frequency of the episodes.
The wine in moderate amount shouldn't have negative effects.
I hope to have been of help.
I appreciate your feedback, Dr. Taka.
Anxiety can cause many different symptoms, some more common some rare, your symptoms are certainly not rare. Of course it should be considered only when other possibilities have been excluded, luckily you have done that.
Thank you for your appreciative words.