Although psoriasis has been the subject of intense scientific investigation, the cause remains a mystery.
As the pieces of the jigsaw are put together, a complicated biochemical and immunologic picture slowly emerges.
Whatever the final mechanism turns out to be, it will be complex.
Certainly, psoriasis runs in families. It is therefore surprising that the genetics of such a common disorder have not been clearly worked out.
One estimate is the risk of psoriasis is 1 in 3 if the father has psoriasis and 1 in 5 if it is the mother.
It is not possible to predict if a particular child of an affected parent will develop psoriasis.
We do know that the condition is not contagious, is not related to diet or to any specific occupation, nor is it related in any way to AIDS or leprosy.