Dear AKC: When I take my floppy-eared dog to be groomed, he sometimes comes back shaking his head like his ear is bothering him. It appears to be a little irritated. He does occasionally get ear infections. Is there any connection between his grooming and ear infections? - Shaking My Head
Dear Shaking: Grooming, per se, doesn't cause his ear infections, but if he is prone to them there are several things that might be happening at the salon to irritate a pre-existing condition or susceptibility.
Most outer ear canal infections are caused by overgrowth of bacteria and yeast. Water in the ear can create the moist environment for this to happen. Another possible cause is debris that gets stuck in earwax that causes irritation, inflammation and infection.
So when your dog gets a bath, he may be getting water in his ear that starts an infection again. Also, while drying, that warm floppy wet ear covering the ear opening may create enough moisture to cause bacteria overgrowth. Or when he is trimmed, hair could be falling down into the ear canal, again sparking onset of another infection. I don't recommend any home remedies to treat this condition, but keep a supply of medication from your vet on hand when these early symptoms arise.
A better way to prevent problems in the first place is to keep the water and debris out of his ear canal. Since he is a floppy-eared dog, I would suggest putting cotton balls in his ears during bathing, drying and when they clip the hair around his head and ears. At least this way you can remove two possible situations that might trigger another ear infection.