First off the bat, let’s get one thing absolutely clear:  Lupus is neither infectious nor contagious.  That means you can’t catch Lupus from somebody who already has the disease.

So now to what does cause it.

While there are no definitive answers, from what I’ve read, experts believe that (in those who are susceptible) Lupus can be triggered by either one or more environmental factors or by genetic factors.

Genetic factors include an increased risk of developing the condition if you have a close family member who already has Lupus, or another similar autoimmune diseases, such as arthritis, MS and rheumatism.

Here’s the science bit.  Researchers have identified a number of different genetic mutations that mean some people are more likely to develop Lupus. A genetic mutation occurs when normal instructions carried in certain genes become ‘scrambled’, resulting in the body’s processes not working normally. Most faulty genes are associated with regulating certain functions of the immune system, which may explain why the immune system in people with SLE starts to malfunction.

Get all that?  No, me neither.

Environmental factors known to trigger Lupus include exposure to sunlight, hormonal changes (such as during puberty or pregnancy), infections such as by the Epstein-Barr virus (EBV) and smoking.