There are several possibilities for this symptom: either allergies or parasites. Your dog may be allergic to some chemical in your home such as carpet freshener or even the the shampoo used by your dog groomer. Parasites may require a skin scraping by a vet to determine the cause.
Take her to the veterinarian. She has a flea infestations, mites, mange or allergies, any of which are making her miserable. The vet will Rx an appropriate medication to relieve her suffering.
You can see your vet. Your pet may be having an allergic reaction, but more likely you have some kind of infestation, mites, mange, fleas, something requiring diagnosis and care.
