Try putting the words dye sinemet itching into google search engine quite a bit of info. on ingredients in sinemet like dyes causing an allergic reaction. look at additives list any changes, or change of brand ? Other than that if hubby is starting to look more lizard than man a good rub down with some baby oil should do the trick, if it doesn't stop the itching, not to worry as he will probably be smiling at the end of his "treatment".
Dry skin can be a problem with PWP.
Hope this helps x