Hi again Hairloss experts. Sorry to bother again, I forgot to ask if a person who has allergies such as ragweed allergies , and is recovering from a patch of alopecia areata. Can the allergy trigger another patch or more hair loss via the alopecia areata way? I'm just worried my allergy can trigger an immune response and attack the hair follicles. Any truth to that? Is it best to take anti histamines such as cetirizine during the allergy season to help calm things down?