Some soaps can dry and irritate the skin, causing psoriasis to worsen. Look for soaps that moisturize the skin and reduce itchiness. Tar soaps are good for reducing itching, redness, and inflammation. Oatmeal soaps help pain, itching, and redness. Soaps containing aloe and lanolin help moisturize and soothe skin. Avoid deodorant soaps and those containing detergents.