The absence of contact may not induce remission of symptoms.
If one is continuously exposed to small amounts of a food and tolerates it with mild reaction there is no indication to remove it from the diet. If he ever accidentally gets in contact with that food again (eg – in food with vestigial amounts of that food) he may have a far more intense reaction than if he had never changed habits.
For a carefull approach, I sincerely recommend you to consult a specialist! Do not take dramatic approachs as abstinence/severe exposure because they can be very dangerous. Our human body is too dependent of a very complex balancing mechanism of immunity and tolerance!