Both unilateral and bilateral contracts are enforceable in court. For example, a unilateral contract is enforceable when someone chooses to begin fulfilling the act demanded by the promisor. A bilateral contract is enforceable from the get-go; both parties are bound the promise.
Yes, scratching is a form of self harm. Try to tackle this problem while you can because it has the potential to get worse. I started out scratching and now I burn myself with a lighter and cut myself. It's a self-destructive way to deal with overwhelming mental/emotional pain.
These microbes cause significant itchiness and more inflammation, which leads to an itch-scratch cycle conducive to self-trauma via headshaking, pawing, and rubbing of the ears. Any dog can develop an ear infection regardless of ear shape, exposure to water (swimming), or the amount of hair inside the ear canal.