How fast can i make my allergies go away?

Nasal antihistamines: Seem to have the fastest onset of action.

Goodbye allergies: It depends what you mean by going away. If you mean relieving symptoms then many of the available antihistamines can relieve some or all of the symptoms within 1-2 hours. If you are talking about curing allergies that is a different ballgame- that could utilize avoidance of allergens, allergy meds and/or immunotherapy. Even with these modalities, many patients are still not cured.