Why is Lupus always mentioned in every episode of House?

Usually the first diagnosis given is Lupus, or one of them thinks its Lupus. Why is that?

I do have lupus so don't need an explanation on that, but thanks for the info lol, i find it fuuny how it's said every week, just wondered if the producer was havin a dig at doctors or something.

Lupus is actually a group of autoimmune diseases....the symptoms are wide spread, and it affects only about 1 in 2000. I would think it is often used in House because the cases they take on are always of the rare and bizarre nature - Lupus symptoms include (but not limited to) joint and muscle pain, skin rashes, fatigue, mucosal ulcers, headaches, loss of hair, chest pain, high blood pressure, swelling, etc. It's easy to diagnose Lupus as an option with such a range of symptoms.....a common cold or flu could be mistaken as lupus - or vice versa.
I noticed another commonality on House is the amount of Lumbar punctures they seem to do....although not as noticeable this season as the previous two....

It is a running joke on the show. I do have lupus, and even I think it's funny when House mentions it. I even have a t-shirt with his face on it!