I've never heard of dog friendly offices where I live. Dog friendly shops, eateries and pubs yes*. But not offices. I take my dog everywhere I can because of how much he helps me mentally but if anyone ever said they were alergic I'd high tail it out of tere with him and make sure I got in touch with that person later to check on them. Just, be decent.

*these places are not everywhere and are always signed as to help those with phobias or alergies.