Wow, those reactions are scary - and they often come on suddenly, with no prior hint...this sounds like an allergic reaction to a bee, or more likely a wasp sting. For some reason, these tend to be more prevalent in the fall, maybe the critters are more aggressive and inject more venom?

The allergic reaction can happen at any time in one's life, even if there has never been one in the past. My Mom collapsed from a wasp sting on the beach at age 76, and the paramedics who caught the call were insistent it was a stroke, due to her age and no prior history of reaction to stings. If my sister, an urgent care nurse wasn't there, and had not badgered them to treat her with epinephrine, she would probably have died.

Please understand that an allergy to one substance does not automatically mean you are allergic to others, so unless you have reacted to one of the other substances you mentioned, you need not fear them. For example, I am highly allergic to bee stings and tree nuts, but I can eat shellfish and peanuts all day long!

Did the ER suggest you see your primary doctor to get an EpiPen to have on hand for possible future emergencies? Or to be tested for other possible allergies?

Two things to note - EpiPens can be expensive, but there are coupons and other help in paying for them, and they can save your life. IF you carry them with you when outdoors. Mine and my daughter's are always with us - in purse, pocket, backpack - to use on a moment's notice.

Do you have an appointment scheduled with your doc?
Sue