the first thing that an allergy specialist will tell you is to stay away from what you are allergic to. Being exposed to such things makes your allergy worse.
If she has a physical allergy to her co-worker's scent that isn't going to cure it, is it?
All seeing an allergist may do, is (apart from costing her several hundred dollars and a lot more discomfort) is possibly identify the chemicals she is allergic to.Most of which have many pseudonyms, so the list gets pretty long, pretty quickly, for example here is just one chemical that is tested for in cosmetic related skin allergy tests:
Methylchloroisothiazolinone/ Methylisothiazolinone (MCI/MI) Also known as: 2-Methyl-4-isothiazolin-3-one 5-Chloro Methyl-4-isothiazolin-3-one Acticide Algricide Algricid CHSO Amerstat 250 Cl+Me-isothiazolinone Euxyl K-100 Grotan K Kathron 886 MW Kathron CG Kathron DP Kathron LX Kathron UT Kathron WT Kathron GT Metat GT Metatin GT Paretol Parmetol
She then would have to find out if any of those chemicals are present in he co-worker's perfume which requires extensive interogation of the manufacturer.
Then what?
You know what the allergists would tell her? Stay away from strong scents.