Hello and welcome to you and Alfeya! Lots of us struggle with our dogs' allergies so we feel your pain. I agree with Margi, an antihistamine is a good way to start. You can also use plain Benadryl (not children's...it has xylitol in it!). I give one 25 mg pill once a day. I'd also wipe her paws when she comes in from outside. I keep a packet of baby wipes by the door for this.
If none of those work, I'd schedule a vet visit for some allergy tests. If you do get to changing food, I'd try a single protein variety with limited ingredients, with a protein she's never eaten before. But I wouldn't do that until you see if the antihistamines work which might indicate it's something environmental that she's picking up outside. Good luck and keep us posted!