Oh, it is hard when a child has allergy and you have to be , as you say, a detective to find out what causes it. Hope it will go to better and one day your son can be allergy free.
My son had some eye allergy during some years when he was smaller. It started when he was 6 years old. They doctors said there were no real cure or medicine, just time will help when he grows. And that's how it happened, when he started the adolescent phase, the allergy just disappeared.
Btw, the snail is cute and funny with his acrobatics :)
Thank you so much for your kind words, @mipiano. It's good to hear that your son is fine now. I know many allergies are supposed to disappear. Unfortunately they say that hazelnut stays. Let's see how we are going to manage that.
Have a great day!