Psoriasis is a non contagious skin condition that causes rapid skin cell reproduction.  It has also been referred to as a form of autoimmune which causes the skin to turn red and develop scaly patches.  The rapid skin reproduction over existing skin is what creates the scaly patches.  These forms of inflammation frequently occur on joints but can also appear on other areas of the body.  Unfortunately there isn't a cure for this recurring condition but there are several forms of treatments to manage and control inflammation during and in-between occurrences.