My sympathy to your DS, it's awful to experience, and treatments that help some people have the opposite effect on others, this rarely seems to be taken into account by Dermatologists. Eg some sufferers are photosensitive and light treatment aggravates it. One of the major causes of suffering is not the psoriasis but others saying, "Oh well if you did/used such-and-such it would be better", the subtext of which very soon starts to feel like "it's your fault, you could stop it if you wanted to". Often the treatment is as bad as or worse than the disease but try saying that to a dermatologist. Worst is the expression on other people's faces when they look (stare) at you, especially if you are in a swimming pool or playing a contact sport. Remissions are spontaneous and often have no apparent cause. As has been said, it is an auto-immune disease and local (topical) treatments really can't cure it. Little research is done as no-one dies of it, though the suffering can be (and often is) extreme. One day . . . . . .