She keeps doing the hair pulling. The two most common reasons for this hair pulling would be the allergy and the mites. The mites are easy to figure out if a strong dip or medication that will kill them is given. They can be hard to find, but the treatment will definitely make your cat better. Several weeks of the treatment may be needed to get rid of the mites.
Allergies are harder to treat.
There are prepared foods that are good to try to eliminate food allergies. You need to use the hypoallergenic food for a month and feed nothing else during that time. Even a small treat or table scrap during the food trial will mess the whole thing up. If you have not been diligent in the feeding of the food and have not continued for an entire month, then you have not ruled out the food allergy. Other allergies will cause these same symptoms.