Why do lupus patients get nose n mouth sores?

Autoantibodies. Autoimmune diseases like lupus result in autoantibodies that attack your own body in error rather than bacterial or viral pathogens which are supposed to be targeted.This form of attack will manifest itself as sores in mucosal tissues including the nose and mouth.The exact mechanism may be an attack on the mechanism that holds the skin to underlying tissues allowing it to peel away creating sores.
Only about 25% do. Oral lesions can precede or follow skin lesions in about 25% of those affected. The sores{lesions} consist of multiple white plaques with dark reddish-purple margins with possible ulceration.

Related Questions

Can you please tell me why lupus patients get mouth sores? I just had my first one.

Autoimmune. It is an autoimmune disease and can affect the mucus membranes of the mouth. Treatment usually involves steroids and making sure there is not something that is being put in the mouth that causes a reaction. Read more...

Ana 1:320, pain all over, mouth sores, nose sores, extreme fatigue. Pcp thinks lupus, but my dsdna was 1 point away from equivocal. Could it be lupus?

RASH? You certainly describe symptoms of such, but an immunologist and histo-pathologist must be brought into the diagnostic mix. Good luck! Read more...
Primary herpes. It is also possible that it is a primary infection of herpes which will have systemic symptoms you report. Need to be checked. Read more...