Your dog& 39;s dandruff may not show up on dark clothing and embarrass it on a date, but the flakes do indicate a problem beyond just looks. Medications, such as antifungal medications, produce possible side effects such as thinning hair and dandruff, according to University of Arizona. (See Reference 1) One form of mites, Cheyetiella, looks like dandruff, reports University of California Davis.