I did a search on "itching" and found this thread from last year:

Amm wrote:

Apple cider vinegar is your answer for itchies.

1/2 to 3/4 cup vinegar diluted with about 1/2 cup warm water. Pour over your scalp in the shower and let it sit. Shampoo and condition as normal. If you don't mind the smell of it, use it after a shampoo and condition and rinse out with warm water.

Apple cider vinegar restores pH and also breaks down previous build up of shampoos and conditioners amongst a thousand other things.   

I wonder if this would be ok on the Pro-tac? Any ideas? My head is really itchy and I can feel little bumps, I hope Im not having a reaction to the Pro-tac . That would figure, I finally find an extension method that I LOVE and I would be allergic to it.

Em