In the past 6 months I have had 5 episodes of my tongue swelling, quickly, and one episode where my left cheek and left side of mouth went numb. The first time, the symptoms subsided on their own. The second time, I went to the er and received benadryl and prednisone which made it go away. I now carry an epi pen, which I haven't had to use, but also have benadryl and prednisone on hand for occurrences. The last occurrence, two days ago, the tongue swelled within an hour to where it was starting to affect my swallowing. I took a benadryl and two prednisines and within an hour had to repeat the dosage because the first did not help. It took 2 hours before any noticeable difference. None of the occurrences have any common thread when it happens. Any ideas as to what may be causing this?