I painted the trim in my bathroom last year, with white high gloss enamel. I notice places now where the white has turned a creamy yellowish. Also, I have a white nightlite in the room that has turned the same color, only on one side. Anyone have any idea as to what may be causing this?
Presume you are not a smoker? It could be nicotine. Did the people in the house before you smoke?
When we moved into our house, the previous owners smoked and the ceilings were nicotine stained. We painted the ceiling half a dozen times and the nicotine still came through 6 layers of good quality white paint. In the end we had to buy a special spray from B&Q to "seal" it before we painted it AGAIN. It did work but unfortunately I can't remember what it was called. Go in and ask if you do want some.
The only other thing that springs to mind is the quality of the white gloss you used. My dad worked in the building trade for years and always swore that good quality white paint such as Dulux or Crown was worth every penny as it stays white for much much longer!
SarahG beat me to the answer. It's very difficult to get rid of nicotine [if that is indeed the cause]........it hangs around for years and can get everywhere, especially so in areas that are prone to condensation as is a bathroom. Sorry there doesn't seem to be an instant fix. If you do smoke, give it up. If you don't smoke you'll have to try to camouflage it. Good luck.
If the trim you refer to is plastic, or some sort of man-made fibre, there is a reaction between it and the paint which yellows the white. In other words "all that yellows is not nicotine".