They might just be bad quality, or it could be the material of the earrings. It could be an infection or a reaction to the earrings, though. Some people can't wear certain metals, like nickle. Try wearing pure silver or pure gold earrings that don't have nickel in them and see how it goes. It could also be a buildup of dirt or dead skin cells too, so try what I said and see how it works out.
it's a reaction that your ears are having to the metal or whatever product the earrings are made of. that means you're gonna have to spend a little more on jewelry and buy stuff that is PURE silver or gold. Usually it's knickle or knickle plated stuff that makes that smell. also keep in mind that there's simply a build up of stuff such as dead skin cells and dirt. I use Dr Bronners to clean my things and ears too...
It might be the material of the earrings, or they may be cheap. I have never experienced this issue with cheap earrings before, but that is probably the reason. Either that, or it's just your imagination. The earrings may have given you an infection or allergic reaction, too. Check to make sure that's not the problem. Hope this helps! -Pink Carnation