I have a 2 year old shih tzu. He is about 13 pounds. He is affectionate, seems healthy, eats, drinks and sleeps fine. He does not have fleas and just had a medicated bath, ears cleaned, and hair trimmed at the breeder. He goes through phases where he shakes, mostly when breathing out. He also has a skin rash. What could be the cause?

Does he do it when he's nervous or in a new situation? If so, its just nerves and is normal.

If he is shaking and has raspy breathing, than he may need to go to the vet. Shaking can sometimes mean pain.

Anything that seems weird or off should be checked out by a vet just to be on the safe side. If you are concerned about this, take him in.

Most dogs shake and shiver when they are cold or got wet.small breed dogs sometimes shake or tremble for no apparent reason.if your pet is shaking or shivering for a long time then you need to take your dog to the vet andcheck the eyes heart resperiroty rate and other check up to get accurate diagnosis of the cause of shaking.the check up will also cut out the wrong assumption of other types of serious illness symptoms.causes of shaking and shivering include

Fever
Feeling cold
Scared
Addisons disease
Outer ear infection
Ear mites
Food allergies wich lead to itchy ears
Loss of balance