Dog Flea & Tick Collars
We put a flea & tick collar on our dog. Then I started noticing my scalp was itching every night. The collar had some type of odor...not sure if it was a fragrance or the repellant chemical.
Anyway I threw it away as a test and my scalp stopped itching.
So, watch out for that one. (I guess I will just go back to picking off the ticks...)