The only reason this came to mind was the repeated antibiotic uses.
First, you are using a dermatologist now, right?'
Fungal keeps coming into my mind because of a past experience. Very different, but the failed antibiotics haunt me.
Willow was very ill, looking like pneumonia. Antibiotics made her better while on them and for a short time after. Then she'd be sick again. I know we did the antibiotics more than twice, it's been a long time ago. The vet finally decided it must be fungal and sent me to a pharmacy almost 50 miles north and the fungal meds weren't cheap. But it was too late, she hadn't gotten the correct medication soon enough. Just hearing about multiple, failed antibiotic use brings back bad memories.
If you have any questions, at all, do not hesitate to ask your vet. Even if it's "only" a gut feeling, you know your cat better than anyone. Remember, there is no stupid question, only the question never asked.
I am not a cat lady,
I am The Cat Lady!