Cat with allergies

[mizbirdy]

Does anyone else have a cat w/allergies?? I have a siamese cat that is about 3 or 4 years old (she's a stray that adopted us!) and about 1 1/2 - 2 years ago, our vet diagnosed her w/allergies & prescribed prednisone for her. It's worked for the most part but now she's sneezing again & she's all stuffed up. Her eyes are clear & I don't think the prednisone is working for just the stuffiness. She's eating fine (LOVES the moist food I give her every once in a while). Has anyone heard of this or have a cat with something similar?? Also, she's an outside only cat.....