Chris
Your son should try to have a alkaline ph balance. Try skipping breakfast and have him drink lemon juice (2 lemons squeezed with filtered water about 12 ounces) every morning upon arising. Look into coral calcium to get a proper alkaline balance and get a ph test to see if his body is acidic. He could have food allergies. I have had psoriasis since I was a kid and know how frustrating it can be. Mine has just about disappeared because of my focus on the acid/alkaline balance with 80% alkaline foods and 20% acidic. Read up on this topic. Do a search with key words "alkaline Edgar Cayce psoriasis" and you will see more success than using topical creams because the healing will come from the inside. Hope you will find the right therapy for your son.