It's possible to be allergic to soy, I don't think vitasoy is good for babies though, doesn't it have sugar and other stuff? You can give sugar free natural soy milk again in a few days and see if the symptoms return.
Ah I see, if it's a very small amount it's unlikely to cause allergic reaction plus the rash would appear in less than an hour. I think you can still try giving soy milk in very small quantity and see if symptom returns, keep Zyrtec on stand by if you have.
Super Mum
Is it only on the leg? A bit odd for food allergy rash to only be there.
Super Mum
Its a possibility. Perhaps you cn monitor his subsequent intake.
Ha