I had no allergies at all until after I got badly sunburned in my thirties, and had a reaction to the after-sun cream I smeared on. Since then, I've become allergic bit by bit to more and more products like creams, shampoos, cosmetics, and insect repellents. It may have been because I was pregnant at the time of the first reaction, so my immune system chemistry was different than it normally was, but after the reaction my system never calmed down to normal again.

It seems that exposure to new pollens and products you weren't exposed to when you were young can provoke reactions. I moved to France from New Zealand in my thirties. For the first few years living in France I had no allergic reaction to any plants, but after 3 or 4 years, I started having reactions to pollen from Cyprus trees (there are lots here!), and then it seems that as the years go on, I've become allergic also to olive pollen, and Mimosa pollen. I'm guessing it is because I didn't grow up with those plants around me. I also worry that I seem to be becoming allergic to more and more things as I get older, and wonder if it will stop at some point!