mustard home challenge

[garliclover]

Just a silly question, really: there are a few WF, DF and EF things that I would like 2yo DS to try (e.g. Sainsbury's freefrom fish fingers) But they contain mustard and I'm a bit nervous because he hasn't ever eaten anything that contains mustard and he does have a tendency to be allergic to practically every common (and uncommon) 'problem' food. He's severely allergic to sesame, so I'm particularly worried about mustard seed.

What do you think I should do? Try him with a little bit of fish finger one day, and a bit more the next, and so on? Or dab a bit of English mustard on his arm and then his cheek, and the next day give him a fish finger?

have access to an immunoligist? or pead allergy clinic? ask them about this and see if he can be tested.
you have to make sure the mustard is not cross contaminated with other seeds that he is allergic to, just to make sure test is accurate.

Thanks for your replies. babyb, yes we have epipens and live quite close to a hospital. I suppose it's not so much a fear of the reaction (though that is present too, of course) as wondering which is the most effective way of testing at home. eragon, he is already under the care of a paed with an interest in allergies, but his list of allergies and his allergic history are so complex and the paed is so busy that we only have a limited number of questions we can ask at each visit! They always try to limit the number of tests to as few as poss. So last time it was only the big 3 (wheat, eggs, milk) because those are the ones he's likely to outgrow first and we are aiming for a hospital challenge for those. As for lentils, other legumes, sesame and nuts.... we have to wait until he's tested for those again, and avoid all of them for the moment. Thanks for the advice about cross-contamination -- hadn't occurred to me, so will make sure.