Why does cold medicine make my head to itch?

I’ve noticed this phenomenon before.

My scalp does not itch ordinarily. I do not suffer from dandruff or psoriasis or any other skin ailment.

But when I get a head cold and take an over-the-counter medication to relieve the symptoms, my scalp itches.

I’ve always assumed it was related to the medication drying out the mucous membranes in my sinuses.

Can anyone corroborate this or offer alternative explanations?

It would help if you told us the ingredients of your cold medicine.

Sorry. I see your point.

Chlorpheniramine maleate…4 mg
Pseudoephedrine HCI…60 mg

Chlorpheniramine usually reduces symptomatic itching, but a lot of people report that pseudophed causes itch. Perhaps on the basis of local vasoconstriction or nerve irritation.