No, you need to take her to the vet. She may need a shot of prednisone to temporarily stop the pruritus and suffering before she develops secondary skin infections.
Discuss with your vet what testing options he recommends. Ideally you should see a veterinary dermatologist.
However give your vet a chance to treat her condition first.
Please use the search engine, tons of information on this topic.
/forums/topic/allergies-and-itchy-dogs/
Ps: It sounds like environmental allergies. It probably has nothing to do with the food.
