Have you ever done a candida cleanse? Candida produces "leaky gut syndrome" which allows for undigested particles of food to go into the bloodstream causing allergic reaction. I think that's how I became allergic myself.
I heard on Hay House Radio Dr. Mona Lisa Schulz say that whenever we feel frightened, threatened and/or somehow not safe in our environment we are more likely to develop allergies and/or have a flare-up. This makes sense since allergies are closely linked to our adrenal hormones which come strongly into play whenever we are stressed.