★★★★☆
By far and away the most helpful thing I've found in my battle against SD is salicylic acid - The strongest over the counter percentage is 3 percent - this helped me but was not enough. My doctor prescribed salicylic acid at 6 percent prescription strength and that applied twice a day keeps it mostly under wraps. Once or twice a year it flares up despite the salicylic acid cream, usually at the beginning of summer and winter - at these times I use a lot of apple cider vinegar and sulfure masks in addition to the prescription strength salicylic acid cream.