Dogs with long, floppy ears are prone to ear infections, and Shih-Tzus are certainly not immune. My oldest just got treated for one.
At first, I didn't even realize he had an infection. When I was growing up, we had a Lhasa Apso and whenever she got the infection, there was a distinct odor that came from her ear so we knew it was time to go to the vet. However, when I checked my oldest, there was no odor so I let it go longer than I should have because I thought that it was just overly itchy and perhaps a bit irritated because of this scratching. I realized something was wrong after my husband told me he got up in the middle of the night and found our oldest scratching his ear and crying. That was enough to convince me something wasn't right. I immediately made an appointment with the vet and, lo and behold, he had an ear infection.
So what are the signs? Assuming there is no odor (which is a dead giveaway), this is what you need to watch for:
1. repeated scratching of the affected ear
2. repeatedly licking the paw that scratches the ear (in our case, he would scratch, lick, scratch, lick over and over)
3. shaking the head
4. rubbing the head against a carpet or floor
The vet took a swab from his ear and tested it. It turned out he had a yeast infection. They also said his ear canal was thickened due to the infection. They flushed out his ear to clean it. I was given antibiotics and ear drops that I have to give him twice a day.
Already I am seeing signs of improvement just after a day. He sleeps a bit more (which is probably the antibiotic) but when he's awake he seems to have more spunk to his step. Most importantly, he is not scratching his ear anymore.
Looking back, I was stupid not to have gotten him to the vet sooner. Sometimes we think we can diagnose a problem, but in the end we're not experts. I was relying on past experience, other people's knowledge and what I read on the internet. However, nothing compares to having a vet have a look at the problem. So if you notice these types of behaviors in your dog, take them immediately to the vet to have it checked out so your pet doesn't suffer any longer than they have to. Dogs can't tell you when they're in pain, and my little guy probably endured this pain and discomfort for longer than he should have.