Not just California. Tennessee, Pennsylvania, West Virginia, Michigan, Oklahoma, Florida, Vermont also require COMLEX. Other states may require you to take an OMM exam if you are using USMLE for licensure.And all 3 COMLEX if you want to gain license in CA due to separate osteopathic medical board.
You are only required to get AOA approval if you want to practice in OK, PA, MI, FL or WV.
Protocols for AOA approval are here.
There's a published core curriculum for intern years by specialty. This is what you're probably up against in demonstrating to the AOA that your derm program meets AOA requirements.
I think that the proposed core curriculum above is outdated, because I recently went on an IM residency interview at an ACGME school where the program director told me that the "1 month of surgery" the AOA requires for IM has been waived. This makes sense, as not a single ACGME IM program requires a surgical rotation, so I don't see how anybody would have been approved. I've emailed DO-online about an updated core curriculum list, and haven't heard back. Does anybody know if there's an updated list out there?