You should not overdose your dog with Advantix - use only as directed on the label - Advantix probably did nothing to help with the itching. I doubt it is mites or anything like that since it cleared itself up. I think it is entirely possible that your dog is responding to something at the groomers, how often do you take your dog in??? It could be the shampoo, it could be the groomer using a dryer - it could be most anything. Winter weather is drier and it could be the combonation of being groomed and the dry weather is too much.
If you take your dog in again, have the groomer use conditioner on your dog and stress to use the medicated shampoo you bring in with you.
Good luck

What kind of dog is she?

Having groomed dogs for more than 30 years (in the past) I can tell you what I know. Many dogs will react to shampoos and rinses that groomers use although I suspect it is unlikely that this is the case. She is probably reacting to dry skin and the Advantix. She could have contact alergies and after the grooming, both the clippers and the bath have irritated her skin. I suggest that you have her groomed more frequently or do her yourself (keep her brushed out) so that her skin can breathe and add olive oil to her diet. Do not bath her unless she is smelly as bathing only washes out the natural oils she produces to protect her skin. It is often just a problem of dry skin in the winter and many concerned owners just want relief for their pups so they resort to emergency measures. If you do not see any obvious critters on her, and many you cannot see, and are not scratching yourself, chances are it is her skin. Many dogs also react to the clipping itself (much like yourself after shaving.....parts)and a good rub with a nongreasy conditioner diluted with water in a spray bottle is all it takes to offer her some relief. If you must bath her, try a mild shower gel, oatmeal slurry or buttermilk. It is very soothing. :)

This is not to say that she doesn't have a skin mite but unless you are itching yourself, I see no sense in wasting your money until you have tried some of these other suggestions. :)

I hope this helps. :)

Ginny

From the history it does not sound like Scabies mites (or fleas, either)... for several reasons. One is that dogs with scabies are usually intensely itchy and nothing seems to help them until they get rid of the mites. Two, scabies mites are not that common in pet dogs, and unless you just got this dog off the street or from a pound, it is unlikely she got mites (have to get them from another dog, usually). Getting scabies from a grooming facility is extremely unlikely as most dogs with scabies are not the sort of dogs that would end up at a groomers in the first place. And scabies mites tend to stick pretty tightly to their host, only coming off if scratched off violently, and then they have to survive in some sort of bedding waiting for the next dog to come along. No grooming facility is going to put successive dogs in cages with used bedding. So don't blame the groomers for mites....

Scabies mites tend to cause a lot of sores, rashes, usually around the head and elbows. They are hard to find with a skin scraping, but they are fortunately very easy to get rid of (though Advantix will not do the job- has nothing in it that kills mites).

Sounds more like as others have suggested, it is related to the bath. I see this very commonly in pet dogs that have just been to the groomers. All shampoos dry out skin (some less than others) and many dogs react differently to some of these products than most dogs would. So being itchy after a bath is certainly not unusual. For dogs that need to be groomed and tend to itch afterwards, I do recommend changing shampoos to those with products that are either soap free, hypoallergenic or at least have no flea products in them... and follow every bath with some soothing, moisturing, anti-itch, leave-on conditioner. Or, groom these dogs less often. This will not guarantee no itch, but it will probably help at least.

Thanks for your replies. We did change shampoo, with a hypoallergenic one from the vet. We re-washed her with it a few days after we'd been at the groomers, and it did seem to help.

There's no question of overdosing with Advantix, first instance we just applied it as directed, when it was due (after the grooming, since its effectiveness is lessened if the dog's bathed too soon afterwards.

This time around, the groomer supposedly used our shampoo, so as an experiment, I used our last remaining dose of Advantix - she hasn't had any applied since August or so, since it's a cold climate here and there are no fleas around (we use it mostly for ticks, which are bad around here during the season)

WIthin a day or so of applying the Advantix this time around, the itching seemed to disappear - quite dramatically. She has had some small scabs on her head, and 'front armpits.'

The only other possibility was her playing in the snow - she was rolling and burrowing in it (she loves to play) which could have 'rinsed' her perhaps or was just soothing. Sounds far-fetched to me.

She's an "American Labradoodle" ie a Standard Poodle/Lab hybrid, first generation. We've never given her Olive oil (interesting idea) but she gets fish oil (salmon oil and cod liver oil) every day, and we have noticed in the past she scratches more if we run out (although she's never had scratching issues like the problem I've posted here, the other instances were minor.)

The leave-on conditioner's an interesting idea - I'll see what's available.

I have to admit we could brush her more often. As for the winter suggestion, the first instance of itchiness happened in spring - May - so that shouldn't have been an issue, although we live in a very dry climate.

What about the groomers tools. Will they pass the mange to other dogs?

Good groomers should be sanitizing their tools.

How old is she? Under a year and if there is minor areas of hairloss, it could be demodex mange (puppy).

Does she have hairloss/rashing in any specific area? Around the rump I would assume flea allergy, or could even be food allergies. You may try to change up her flea prevention if you use topical, I find some animals in our shelter do better with internal if they have flea allergies.

Have you tried new food/treats? You may try to minimalize what you feed to see. Stick with one protein (chicken/beef/fish) a lot of animals turn out to be allergic to that rather than grains. Even your internal preventions have flavoring that could cause allergies.

If you can afford it and that's not helping any, get her tested for allergies. That's the final know all of whats wrong if its an allergy. You don't have to pay for the shots, but it'll give you a good idea of what to keep her away from (food, plants, other animals...).

Lastly you mentioned she was itchy after the bath? Could the groomer possibly left some shampoo on her? Maybe ask them next time to make sure to give her extra rinse time since her hair is thicker and she may be more sensitive to leftover residue?