What is 'Comparative Advantage' Comparative advantage is an economic law referring to the ability of any given economic actor to produce goods and services at a lower opportunity cost than other economic actors.
Though dandruff does not cause dry scalp. They are different health problems which are caused by different factors and needs different treatments plans to tackle them. It becomes absolutely necessary to first diagnose the problem along with its causes, before planning a treatment plan for the ailment.
I would use a dandruff shampoo anyways because sometimes even when you don`t have dandruff, it still helps dry skin on your scalp. This is most likely what it is. Still bring it up to your doctor though :) source: My scalp is very itchy, but i don`t have lice dandruff or have used any new products.