ESA CAT in 3 bedroom shared housing

[Jaimi Sun]

Hi. I have 3 bedroom condo for rent mostly to the college students. I have all 3 rooms already occupied and have no pet policy. One of the tenant won't renew her lease, so I am in the market to replace her. One prospective reached out and very interested but has an ESA cat. (I do not know if she has a legit letter or not) Regardless, I understand FHA I can't deny her application based soley on the ESA, but if the one of the current tenant have allergy issue, can I deny then? Is there any legal ramification? Will I get in trouble if I say no to ESA because of other tenant has allergy? I understand if this person is renting the whole apartment unit, but how does the ESA works out in shared housing?