My sister’s daughter is allergic to a lot of things. She is so sensitive that she can walk into someones house, take a few breaths, and know if she will have any problems due to their pets or whatever.
They had a cat that she was not allergic to, but she is allergic to most other cats and dogs. She is taking allergy drops (daily by mouth) that were prescribed by a doctor. These serve the same purpose as allergy shots that are usually given weekly. The drops are a lot more convenient. Something like these I think.
Edit – and that cute little black puffball will be a lazy, aloof, sleep machine before you know it!
They think that it will take her about a year of treatment and she should be ok with cats.