Cat Licks and Pulls Out Hair in the Summer?

My cat licks and pulls out her fur only in the summer. She is an inside cat. She does this till she is almost bald and bleeding; what can I do? I have tried giving her Benadryl, antibiotics, and using medicated powder. The vet said it is only a skin irritation, but it happens every year only in the summer. It looks very painful and if not bleeding, it is oozing. The rest of the year her fur is beautiful. She is albino and gorgeous most of the time.

By Judy