didn't use epipen, just antihistamine, but decided to do what we were told we should and go to hospital. It's a long trip so of course by the time we get there she's better.
Ask if they can offer any help in tracking down the cause and they say "talk to your gp" - who we explain knows less than we do. And "avoid any processed food" - great, they will never be invited anywhere ever again. They did check her blood pressure.
Off to try out American sites to see what an American hospital would do!