Just ask people to refrain from touching you. With the exception of my wife and daughter no one touches me. Everyone has been understanding even without explanations and the only time it has become awkward is with hand shakes at the end of an interview. I've learned to pass this off as having a cold and not wanting to give it to them. And one time during my wedding reception were a man I didn't know shook my hand while I was going to the bathroom..... I just pass that off as drunkenness although at the time it was severely disturbing.