More than 4.5 million adults in the United States have psoriasis, and about 20 percent of them have moderate to severe cases.
Psoriasis is rare in Native Americans and uncommon among Asians.
You can get psoriasis at any age, but it shows up most often between the ages of 15 and 35.
One in ten psoriasis patients develops the condition during childhood, and 75 percent of patients show symptoms before the age of 40.
The earlier psoriasis shows up, the more likely it is to recur and to be widespread.