I have chronic hives mostly on my face. I m taking allegro in the morning and zrytec at night. I m also taking ranitidine to block the H2 histamine receptor. Is it risky to stay on antihistamines for too long. I started with prednisone and the same two antihistamines but had no relief - still broke out with hives. Now I m taking methylprednisolone and the antihistamines. I would like some feedback concerning this medication plan and again is it dangerous to stay on antihistamines for a long period of time. I will see my doctor in two weeks and if there is no change in hives I will stop what I m taking. I was considering staying the Zyrtec because I sleep better.