There is some evidence that lupus and other AI diseases can be triggered by chemicals. I don't believe that there is any conclusive evidence and proving a trigger in any individual case is difficult if not impossible.
If you do a google search of lupus chemical triggers you will find a number of articles on possible triggers. That is not the whole story even if you can find a link. Your immune systems are vulnerable to the trigger and that is probably a combination of genes.
It is known that things like cancer, viruses, some meds, and possibly stress can trigger AI diseases. Possibly there is some unknown chemical agent in your house that caused your problems...or possibly it is just an incredible coincidence. The reality is that most of us will never know why we got sick. I was seemingly healthy for 62 years and got mctd out of the blue....or so it seemed. In retrospect there were signs of it at least 17 years earlier. These diseases are maddening.
Hope you can get some answers but if you do you will be the exception.
Mixed connective tissue disease (systemic lupus, scleroderma, polymyositis), Raynauds phenomena, Hypertension, Barrett's syndrome.
Meds: prednisone (9mg & tapering), 150mg imuran, lisinopril 40mg, maxide 37.5/25mg, norvasc 5 mg, folic acid, potassium, aciphex 20mg, multi vitamins.
Maintain your optimism and you can beat the odds.
"Although the world is full of suffering, it is also full of the overcoming of it." Helen Keller