Seborrhea (I think that's how it's spelled) aka dandruff can be a symptom of Parkinson's. My husband gets it on his face, under his beard. It is itchy.

I would trade that if I could for my neck lockups! One of my nerologists is working on that for me....I have a Parkinsons doctor but she says take another Carbadopa- Levadopa but a doctor that actually wants to help is hard to find..I did not know what was happening to me the first time I actually experienced one of the lockups but learned going to my PD group meeting that people actually have them in their legs or other places other than their necks...I look like I am having a stroke and I do take a Carbadopa-Levapoda because it hurts and it takes about 30 mins. for it to pass. So a itchy scalp sounds easy next to my lockup neck...do we have to get something new all the time....I am sick of it.! Not to complain but why can't we have lost of appetite or something like no desire to hit someone or even don't like to cook three meals a day...I can sign up for that today....and I like to cook. I think maybe you need to change your shampoo!