Since starting with the olive oil I have not notice any itching due to it, but every dog is different and some may not be able to tolerate it like others. During the summer months some of my guys tend to itch more which of course causes the matting due to the heat. The hotter it is the more they sweat which will cause them to itch more.
Here is how I apply the oil:
1. I shampoo with a good cleaning shampoo (I have been using Coat Handler or Biolage lately) and make sure I am rinsing it out completely to get the oil back out of their coat.
2. I use a mosturizing conditioner to help protect the coat from damage (I use either Coat Handler or Biolage Hydrating)
3. Then after towel drying them, I will brush out their coat completely and blow dry the coat about half way dry. Just enough to pull the water out but not completely dry.
4. I put about a quarter size of the oil in my hands and rub them together and then start at the ends of the coat and apply evenly around the end and work up to the root.
5. Once the coat is lightly coated with the oil I then finish blow drying them...it will take longer for them to dry due to the oil.
6. After they are dry I take a towel and just lightly rub off any extra oil that is left on the coat. (I do this as to not get the oil on the furniture)
I try to make sure I bath them every 6-7 days at the very most. I have found with the olive oil I don't have to bath and rinse the oil out as often as I have had to with other products. If I do notice any itching I will just use a shampoo and conditioner and leave them out of oil for a couple of days to get their skin some time to breathe...but I really haven't had any problems like I said.
I really hopes that this helps you. I hate that your guys are itching so badly right now. My suggestion there might be to see if your vet will give them a shot to help stop the itching and stop that cycle.