Lupus pneumonitis is a general term for acute infectious inflammation of the lungs in people with diagnoses associated with connective tissue lesions, such as lupus erythematosus, scleroderma and other diseases of an immunosuppressive nature.
Lupus pneumonia occurs as the disease progresses, caused by chronic inflammation of the immune system, which leads to damage and dysfunction of cells involved in the body's immune responses. This can make the body less effective at fighting infections, making it more likely to develop infections such as pneumonia. In addition, chronic inflammation can suppress the immune system, so the body cannot effectively fight infection. This leads to more severe pneumonia.