''You Don't Want To Know'' is the eighth episode of the fourth season of the American TV drama House and the seventy-eighth episode overall. It aired on 20 November 2007. Notably, in this episode the differential diagnosis is confirmed as lupus despite the fact that 'It's not lupus - it's never lupus' is a phrase often used to the point of catchphrase by the eponymous Dr. Gregory House.

Can we conclude that was there ever a case of lupus on house?
yes