Not taking your wig off or lack of maintenance
The general perception is that human hair wigs or toupees are naturally itchy because they are a foreign object applied to your scalp. This, of course, isn’t true. But what doesn’t help matters is a lack of maintenance for the hairpiece or not even taking it off.
In general, it’s not recommended to keep wigs on while you sleep at all. And while toupees can be slept with and can last months, it’s important to regularly maintain and wash them. This not only keeps the hairpiece clean which helps prevent itchiness, but also allows your scalp a chance to breathe and get clean as well.
After all, dirty natural hair can also lead to itchiness.