I Am 54. I Have No Known Allergies. I Had

I am 54. I have no known allergies. I had a hysterectomy 11/1 and 5 days later I had extreme swelling of the tongue, lips and mouth and wound up in the hospital. The GPs said it was an allergic reaction but I had not been feeling well so I was taking no meds and eating next to nothing. That passed a couple of weeks later my right hand swelled, I took Benedryl and within a couple days the swelling went away. 3 weeks or so my other hand had the same issue. Last night my right foot swelled and itched and again I took benedryl and it helped reduce the selling and itching. I have been paying attention to what I eat and put into and onto my body. There is no pattern and no one food or combo that is triggering this. I do not want to go to an allergest as I truly do not believe that is the cause. Can there be any underlying casuses within possibly triggered by the surgery since this did not happen prior to it. Could my body be fighting itself? Thank you