During the summer, when I use products that contain silicone, I tend to break out more than when I use the same products during the winter. I have therefore concluded that the silicones present in those products tend to cause me clogged pores, especially in the summer when I perspire.
The same is true when I use products with mineral oil or petrolatum. Although both are considered non acne-causing, when I use products that contain either ingredient I tend to break out. And many times they cause me large, painful, deep, pimples that are difficult to treat.
There has been some mention of pimples being caused by sweating and using silicone based products in acne prone individuals. Whether this is true for everyone, I don't know, but it seems to be with my skin. I know plenty of people who use silicone based skin care products that have no trouble with them at all so it is one of those things that obvisouly varies by the person and their skin type.If you suffer with acne and aren't sure the cause it might be worth reading the ingredients on your skin care products and seeing just what they contain.