THE PURPLE WIG A FATHER BROWN MYSTERY by G.K.CHESTERTON

The Duke of Exmoor wears a wig which people believe hides a family disfigurement- namely a deformed ear.  He creates a terrible curse that would befall anyone who sees his naked head.  When a local reporter calls out the Duke for creating a false curse Father Brown, using his understanding of human behavior, challenges the Duke to reveal his secret.