walnut in cake - how long before an allergic reaction?

[islandgirl]

Can you help - both children just had cake with a trace of walnuts in it (1.5%) - if they are going to have an allergic reaction how long before it happens?? And how long before I can stop worrying?!

Not an expert - but don't you become sensitised to things like nuts after the initial exposure? ie., the first time you eat them you are not likely to have a reaction, but subsequent times you may? I think if they were going to react badly, it would be pretty much immediate. Do you have any reason to think they may be allergic to nuts (family history, previous allergic reactions) or are you just avoiding nuts 'til they are older?

thanks for that - no reason to think that they are allergic, but with ds1 only 3 and ds2 only 2, I was planning to wait a bit!!!!!
We were at a friends house having the cake and it is just one of those things. Ds2 is allergic to bananas, but nothing else that I know of. I had thought that there would probably be an immediate reaction so it seems a bit silly to worry if they seem fine.

Ds2 accidentally had almonds (in biscuits) when he was about a year old - he was fine and is not allergic to nuts. I gave him nuts in things from about two as there is no family history of allergies, excema, asthma etc.

My ds is allergic to walnuts, and if it was going to happen, believe me you'd know by now. His lips swell up immediately, after the first mouthful. Marthamoo is right about sensitisation- you won't be able to tell after this that they're not allergic to walnuts, but I'm quite certain that if they haven't reacted by now they'll be fine for now