In Los Angeles, I've found that a lot of PR firms include "fashion" in their list of specialties, but many more times than not, they do not do just fashion. For example, they list the various areas they work in such as health care, automotive, insurance, entertainment, fashion etc. So I've just had to search each PR firms' sites and public information to see if they either name fashion as a specialty or they have fashion clients on their client lists. I think that NY is more likely to have more fashion only PR firms.