If you dream that you have an allergy, your unconscious could be warning you that something in your life is having a dangerous effect on you.This can be an object, a person, or even a lifestyle.
The thing that you are allergic to in your dream can provide you with a clue about what you should be avoiding.
If you dream that you are allergic to a certain type of animal, for example, think about the qualities that animal represents to you.
A dream that you are allergic to a food can be a sign that you have been overindulging or that you are being smothered with too much attention.