A common inflammatory skin condition characterized by frequent episodes of redness, itching, and thick, dry, silvery scales (mine is more of a yellow crust) on the skin. It also can cause joint pain. It hits about 8 out of every 10000, appears to be genetic and occurs more in Caucasians (white folk). It fucking sucks. It normally hits between the ages of 15 and 35 and seems to be progressive. If it gets really bad, like if your whole body is covered, you have to go to the hospital. The body loses vast quantities of fluid and is susceptible to severe secondary infections that can become systemic, involving internal organs, and can progress to septic shock and death. Treatment includes analgesics, sedation, intravenous fluids and antibiotics.
This is not what happens to most people. Most people just use tar shampoo and the occasional topical cortisone or other corticosteroid flavoured treatment. Another terrible thing is that it can greatly increase your chances of skin cancer and cortisone is linked to a few cancers itself. This condition is all over the map person to person when it comes to symptoms. I've had it since I was 15 and have seen it maybe twice other then on my scalp, until I was 25, when it appeared in my ears and on my torso.