What is the difference between primary sjögren’s versus secondary sjögren’s?

Circumstance. Secondary sjogren's syndrome is caused by something else that the body reacts to causing the disease. Primary sjogren's just occurs; most likely from a genetic predisposition. The symptoms and treatments are the same.
Difference. Secondary sjogren's is sjogren disorder that is superimposed on another one (primary), such as lupus and or rheumatoid arthritis, unlike primary sjogren's that is a stand alone condition.