Is Allegra 180mg safe for breastfeeding.

I have urticaria since my childhood.. it appears once in 2 years and everytime it lasts for few months. We were unable to find the trigger point for my condition. It comes under control only when I take Allegra 180mg medicine everyday as long as it is there. Even if I miss for one day , the hives appear on arms , legs etc., and it is very itchy. Fortunately since last one year I did not see the hives and I delivered a baby 4 months back . Am exclusively breastfeeding my baby now. The hives have started appearing again. Can I take Allegra tablet again everyday ? Does it impact my milk supply? Does it get passed on the baby through my milk ? Desperately looking for clarification from any of the doctors... Thanks Vaishnavi