Concerned about dandruff shampoo being too harsh for my hair. Is it??

Hi Again :)I have a question. I have sebborheic dermatitis and my scalp seems to be flaring up quite a bit with the cold weather this year (which is interesting because in the past it used to flare up the most in the warm weather). I know I really need to start using a medicated dandruff shampoo BUT I'm concerned if I do, it could be too harsh for my hair and possibly damage it. Will it?? I admit I haven't used a dandruff shampoo in a long time.What's the most gentle but effective dandruff shampoo I can use that is especially good for scalp disorders? Nizoral? T-gel? Is it okay to wash with these every day? Or what?Thank you!!MariaRelated Link:Maria In Mass