I'm new to posting - not so new to MN as been lurking for a long time.
My son has lots of allergies, environmental, food, oral allergy syndrome as well as autoimmune stuff - coeliac, and EE. During a holiday in the UK (we usually live in Oz and are currently in Singapore, he had strawberries and his face and lips swelled massively - it took 3 days for his face to go back to its normal size even with regular antihistamines. long story short we went to hospital in the Uk and because of his history he was given epipens. Back in Singapore, he was food challenged with strawberries and was absolutely fine. He has shown no reaction to any foods stuff since August until last weekend when I made caramelised onions. Within a minute or two, his face and lips were swelling up again quite significantly - a large dose of diphenahydramine and after a couple of hours he was back to normal.
Could it be the balsamic vinegar? there was only red onions, sugar and vinegar in it. The vinegar did contain caramel and sulfites - could that be it?
Any ideas would be great 