What made people wear white wigs in the 1700s?

The reason that people wore white wigs is the same reasson that all fashion and style trends started. Because someone famous/popular and admirable started doing it. In this case it was King Louis XIII. At that time men already had long hair which they would pull back in a pony tail; but King Louis started going bald. He felt that his balding would cause him to seem weak or less than manly so he had several powdered white wigs fashioned for him. When the King started wearing these wigs, all people of nobility began wearing them. Eventually it caught on in England, Germany, Russia, etc. The whole trend started just because a man in France didn't like the idea of going bald. :) Hope this answers your question.