Why Do The Symptoms Of Itching, Redness, And Rash Associated

Why do the symptoms of itching, redness, and rash associated with my life long problem with atopic dermatitis diminish significantly when my body is fighting off a virus with say swollen tonsils, low fever, etc? I have had the problem since age 2 and am currently 29. Also associated are food allergies to many foods to where my doctor recommends carrying an epi pen at all times. I have coped with the food issues but have never had long term relief from the AT. Thanks, MN.