Yes, In medicine we try hard to work out whether an allergic reaction is either immediate (also referred to as type 1 reaction eg anaphylaxis) or delayed reaction(eg eczema, food intolerance).
An immediate reaction (Type 1 reaction) is usually immediate (or within an hour or 2 at the most) and can be severe involving the whole body as in anaphylaxis. However most reactions are mild and usually involve itching and swelling, and can go away quite quickly (generally within a few hours)
Delayed reactions can take up to 72 hours before you start to show symptoms, examples include eczema and food intolerance.
The reason we need to determine what type of reaction you are having, is that it can affect the kinds of test we can do, and with immediate reactions it can also tells us whether you are at risk of anaphylaxis or not.