I have angio edema.  I began having my allergic reactions after having by-pass surgery in 2005 at the age of 50.  It began as randum swelling (welps) on the feet, neck, adomen, legs and arms.  Then it started to progress to my lips, tongue, throat and face.  At times my esophagus swells from my mouth to the middle of my chest causes cardiac like pain.  I used to get a "warning" with a warm itchy feeling where it was beginning to swell.  Now I get no warning.  At one point when my throat started to swell, I was in the ER every two weeks - given epi, benedryl and a steroid.  They finally determined that I was allergic to iodine, betadine, shell-fish, iodized salt, asprin, ace inhibitors and ibuprofin.  I now take benedryl, fexofenadine, and ranitidine to control the reaction.  I've always been close enough to a hospital and not had to use my epipen.  It does give me peace of mind knowing that I have it just in case I can't make it to an ER.