Redness and itching at bra line and arm pits for weeks.dermatologist gave me cloderm to use for 2wks but doesnt seem to be helping. only med i take is armour thyroid. changed all soaps. zyrtec takes edge off. how do i rule out something bad?

sounds like a contact allergic dermatitis. If so, one of the materials in your bra or a detergent you use or a deodorant your use could be the problem. Suggest you see your dermatologist if no improvement after stopping the above items. Continue the zyrtec and possibly add a more potent steroid cream instead of the cloderm. Sometimes aveeno oatmeal baths are helpful along with unscented soap.