Is It Safe To Take Estrace For Hives All Over The Body?

In 1985 I had a hysterectomy at age 35. I was given Estrodiol and broke out in hives all over my body. They kept me in the hospital for a few days ( how things have changed). I began taking Estrace with no reactions. The Doctor then told me to never take the generic. I am now 65 and a Medicare supplement is going to cost me 5 times more because of the Estrace. Would it be safe to try the generic again. I take one half mg per day. Thank you