If the conditioner said to wash out then I would not put it on her sink in between bathes.
You could fine oil in the herbal store that has jojoba oil or even pure vitamin E should help as well. For itching I know they also recommend oatmeal shampoo.
When you try these products only use it on a very small patch of skin for testing for 24 - 48 hours to see if there is any reaction.
If she has inhalent allergies, talk to your vet about an antihistamine trial. Sometimes you have to try a few to find one that works.
Try a spray-in leave on conditioner for between baths. Ice on Ice or even human Thermasilk can be used. When I bathe in coat handler, I leave in a light rinse of diluted conditioner, especially on Mikey's belly where he gets dry skin.
Summer has the same problem inching around her face and under her chin below the ear . Going to the vet tomorrow to make sure she doesn't have ear mites
or something like that she doesn't scratch all the time but when she does boy does she go at it. the skin is not raw or anything :
can't figure it out still working on it will try the Thermasilk or Ice onIce if I can find it..
Have changed her food to Blue Baffalo ( any body use this) Saw a man at the store and he said his dog had every allergy to man and was losing his hair put her on the new food and hair came back and the inching stop? go figure so were on the new food 3 days now she love it I also put a little hard boiled egg in it I think she likes the egg the best this AM she wouldn't eat it with out the egg.. hope this will start to help