I wasn't sure where to post this but I guess it can be moved if it's in the wrong spot.
I've changed Lilly's food so I'm almost positive that isn't the problem or maybe it is, I don't know. I feed her Wellness Super 5 Mix Small Breed or something along those lines (can't remember the exact name) but keep in mind,
I've only been feeding this for a week maybe a tiny bit longer.
She's STILL itching. Hardcore itching. It happens more after I bathe her than it does closer to the time when she needs a bath again. Like, I just bathed her this past weekend and she's itching pretty bad but up closer to her bath time again it's like her skin doesn't bother her as bad. I'm almost 100% positive her shampoo is irritating her. I use Crazy Dog in the Rainforest scent.
What do I need to bathe her in? I noticed whenever I used my grandmother's dog's shampoo on her she didn't itch that bad but then again she wasn't itching really bad over there to begin with.
Any ideas as to what could be causing this?

Do you think it's something in our house? If you recommend a shampoo, please be specific and give the exact name and kind.
TIA!
Edited to add: If at all possible I'd like it to be scented even if it's just a light scent.