My Son Has Down Syndrome Has Had Surgeries. He Has

My son has Down Syndrome has had surgeries. He has bad case of psoarisis I have tried about everything possible to releive it the plaque on his legs are real bad and thick. His dr. seems to think that a shot would not be wise with everything he has been through, any suggestions what I can do to help him? He is 18 and has had it for a while. Please help