<<Disclaimer: Verify this information before applying it to your situation.>>
 
Whenever I experience an allergic reaction, the visible symptoms begin
approximately two days after ingestion.  This has been extremely
consistent for 30 years.
Andrew
 
Jean Jasinski wrote:
> One of the basic premises of food allergies is that a reaction is
> not always immediate.  In fact, it can take up to 72 hours for
> a reaction to show up although it is very difficult to pin a reaction
> 72 hours later on one food you ate three days ago.  We've seen
> reactions that can be directly attributed to food 10-14 hours later
> (like tomato sauce eaten at dinner causing a bad tantrum at school
> the next day).