Original
Systemic scleroderma only occurs in patients with a genetic predisposition but also requires some type of trigger event. Known triggers are exposure to certain organic solvents and silica dust (often in industrial settings). Researchers also believe that some patients may have an infectious process as a trigger as well.
Exposure to heavy metals and other toxins as well as Lyme disease have been suggested as potential triggers, but the research is not solid that these are actual triggers at this point.