As a matter of fact, there is a pet allergy specialist in Orange County. I used
to bring my
cat there (she had similar problems). I think they were in Tustin, but
to be honest with you, it's been a long time and I can't remember the name of the place....
OK, I just googled it, and I'm 99% sure this is the place:
Animal Dermatology Clinic
2965 Edinger Ave
Tustin, CA 92780
(949) 936-0066
In the meantime, maybe you could try an oatmeal bath to help relieve some of the itching.