Steve Perry is incapable of being afflicted with dandruff.
Fact. Steve Perry's genetics (being Portuguese and Steve Perry) makes him impervious to most afflictions: cancer, high blood pressure, depression, STDs, PMS and, of course, dandruff. In fact, if you looked in his shower, you wouldn't see any bottles of shampoo or conditioner. Well, you would, but you wouldn't recognize them being as such. They're marked simply magic and wonder.
However, every Superman does have his kryptonite, and Steve is no exception. When he's within 50 feet of Neal Schon, he's powerless and vulnerable.