In a word, YES. I have interviewed hundreds of people and have eliminated applicants because they had streaks and highlights that were not normal hair color. Most employers want people who represent their company and present a competent and professional demeanor. With the competition being what it is in the work place, you need every possible edge. Purple highlights, facial piercings and obvious tattoos will not give you any kind of advantage in obtaining a job in a professional setting.

As one answerer already said, it may not exclude you from working in a porn store or setting of that type, but in most places it will get your resume put in the, "I don't think so" stack.