Some dogs shake their heads just to hear their collar tags jingle. (Wouldn't you?!) Most dogs, though, they only shake their heads when their ears are bothering them. They can't really reach them with their paws, after all!
If you've noticed your dog vigorously shaking their head from side to side, especially if it's a behavior that's popped up all of a sudden, here are a few possibilities:
Infection of the Ear
Your dog's ear is the perfect vessel for bacterial growth. It's warm, moist, and dark; yeast infections and other bacterial infections are incredibly common in canine ear canals. Infections can be pretty uncomfortable, causing the kind of itching and inflammation that encourages your dog to shake their head to ease the sensation. Obvious signs include redness, discharge, or foul odors.
Allergies are also a common culprit of head shaking. If your dog suffers from seasonal, environmental, or even food-related allergies, skin inflammation may be a side effect. The ears are particularly susceptible to itchiness and are difficult to scratch. The good news is, allergies are usually treatable with medication and/or behavior modification.
Did you know your dog can get ear mites?! Yuck. Mites can actually be transferred from one infected animal to another and though they're more of a pest than anything, serious cases can see real complications. Itching, shaking, and crumbly discharge are the most common symptoms to look for.
Vasculitis is the scientific name for an inflammation of the blood vessels. Certain breeds such as dachshunds and terriers are predisposed to developing vasculitis of the ear because of an immune disorder. Other causes include frostbite and even fly bites. Dogs with vasculitis usually develop crusty lesions on the outer rim of their ears that can actually burst during vigorous bouts of shaking.
Water in the Ear
Did your dog just go swimming or get a bath? They could just have an earful of water! Happens to the best of us.
Noticing a lot of head shaking?