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Question: In a previous issue of the "Scleroderma Voice" magazine, mention was made to an environmental factor in scleroderma: exposure to silica dust. I'm wondering if we should be concerned about the silica gel used in drying flowers, and the silica packets found in vitamin bottles, shoe boxes, etc.? Answer: Scleroderma and similar illnesses have been associated with a variety of environmental and chemical exposures in several reports. The first report of scleroderma associated with silica exposure was nearly 90 years ago in Scottish stonemasons. There have been subsequent reports identifying the illness in gold miners and coal miners exposed to silica. In more recent years, scleroderma and scleroderma-like illness have been associated with exposures to other substances in industrial settings. Examples include vinyl chloride used in the manufacturing of plastics, epoxy resins, and many solvents. Some of the solvents that have been implicated are trichloroethylene (TCE), benzene, xylene, and toluene. "Pseudo-scleroderma" illness was recognized following dietary exposure to toxic rapeseed oil in Spain in 1981. Use of the contaminated nutritional supplement L-tryptophan was linked to the outbreak of eosinophilia-myalgia syndrome in 1989. Exposure to potentially toxic products and chemicals is commonplace in today's world. However, it appears that only a very few individuals develop scleroderma or similar illness. Other factors are likely important in determining if illness results. The frequency, duration, and dose of exposures are important. In the case of industrial solvents, possibly some second agent dissolved in the solvent may also be playing a role. Even genetics in these cases appears to be influential in making some individuals more susceptible to developing or perpetuating illness. There is a variety of drying agents, or so-called desiccants, that are widely used in the electronics, optics, food, and pharmaceutical industries. Some examples of these products used to control moisture and humidity are silica gel, clay, calcium oxide, and calcium sulfate. Those desiccants, and the containers in which they are packaged, have to meet FDA standards for safety. In general, the containers are made of tear-resistant Kraft paper or specialized polyethlylene. These materials have microscopic pore sizes that allow moisture to pass through and be absorbed, but are small enough to prevent dust of the drying agent from escaping in any significant amount. |
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