What Can I Do About Hives I Believe To Be

What can I do about hives I believe to be from stress when Benadryl doesn't seem to be helping?
It seems to work for awhile than out of nowhere the hives return and is accompanied by a burning itch mostly on hands and continuing up my arm. I have itching and small patches here and there on upper back and abdomen and here and there on my legs as well but primarily hands and arms. I am 44 yrs old and am severely allergic to "cillan" drugs and sulfa. I suffer from anxiety, fybromyalgia and hypothyroidism and just had a complete hysterectomy less than 4 months ago as a result of several years of "female" issues.