Summarize this article in one sentence.
Your dog may be experiencing some discomfort. If you see it scratching or rubbing its ear more than usual, that could be a sign of an ear infection. The dog may also whine. Alternatively, your dog may rub its ear against objects, such as furniture or toys. Your dog could be doing this because it's feeling discomfort. It could be a back-and-forth motion, or you may just see the dog holding its head to one side. This can also be a symptom of ear mites. Either way, it's best to take the dog to the vet. You may notice either wet or dry discharge. At first, the discharge may just appear deep inside the ear, but it could also be dripping out. If you don't see discharge, that doesn't mean that the dog doesn't have an infection. If the dog has other symptoms, it's best to take the dog to the vet. Healthy dogs don't have smelly ears, so an unpleasant odor in your dog's ear means something is wrong. A pungent, unpleasant odor ear odor may mean it's infected. Compare the dog’s affected ear to the other ear to check for swelling and redness. It’s normal for the ear to be pink, but a deep red could mean an infection. You may also notice scabbing, especially if the dog has been scratching its ear. The dog may lose its balance and become uncoordinated if the infection is affecting its middle ear. You may notice the dog leaning, staggering, or walking in circles. If you notice a loss of coordination in your dog, take it to the vet immediately as this is a sign of a serious infection. A severe infection can also cause vomiting, especially after the dog has lost its balance. If your dog is showing signs of infection, you should take the dog to the vet immediately.

Summary:
Notice if your dog is scratching its ear. Watch for head shaking or tilting. Examine the ear to check for brown, yellow, or bloody discharge. Smell the ear to see if it has an odor. Look for swelling, redness, or scabs. Watch for loss of coordination or walking in circles. Watch for vomiting.