4yr old Schnauzer rubbing his head

by Shawn
(Oklahoma City, OK)

My family has had several Mini Schnauzers and this is the first one that will come up to us and rub the top of his head all over us.
Could this be a skin disease or something or showing us affection, or something completely different?
Any insight is greatly appreciated.

NOTE FROM LINDA AND MAX:
Don't know about that Shawn, if his fur and skin look OK around his head, he is probasbly just itchy.
Max does this a bit with us, too. He also loves to rub his beard up and down on things, including us. In this case, his whiskers are just itchy, especially after he has eaten a a meal.
Anybody else experienced their dog rubbing the top of his/her head or beard?