This informative and relevant excerpt is from Dr. Amy Meyers’ website, taken from her article on toxins and autoimmunity:

“We absorb them [toxins] through our skin: Your skin is your largest organ and your main barrier to the outside world. Substances ranging from the beneficial to the bad come into contact with your skin and can be absorbed into your bloodstream. That includes the chemicals in soap, makeup, lotions, and cleaning products, and even heavy metals and pollutants in water.

The average person uses 10-15 personal care products per day, each with 125 different ingredients, and many of these chemicals are approved for use by the FDA with little or no safety testing. . . . Think of your body like a cup, and toxins like drops of water: if your cup is already full because you have a leaky gut, a poor diet, infections, and stress, those small, cumulative toxic exposures cause that cup to overflow. When it does, you’re pushed down the autoimmune spectrum into full-fledged autoimmune disease.

Toxic Triggers: How Toxins Cause Autoimmunity
The effects of toxins on our bodies is complex. After all, there are thousands of chemicals out there, and we’re just beginning to understand how they work on the body–not to mention, how they work in conjunction with one another. What we do know is that a heavy toxic burden puts you at greater risk for developing an autoimmune disease, and there are a few theories as to why.

One thought is that certain toxins, especially heavy metals, physically damage your tissues. Your immune system no longer recognizes these damaged cells as part of your own body, and attacks them, thinking they’re foreign invaders. Another theory is that the damage inflicted by toxins elicits an inflammatory response from the immune system. The constant assault of chronic exposure puts the immune system on high alert. It begins attacking everything–including your own tissues.”

Source: The Autoimmune Solution Pillar III: Tame the Toxins – Amy Myers MD