In what way can skin change color without a change in melanin production?

Medical problems. If you have liver damage or certain types of cancer, kidney failure, anemia, and other medical conditions you can have changes in your color tones. Hormone medication as well as pregnancy can cause melasma and some prescriptions can also give those side effects. Speak with your doctor about your medical condition, medication list, or diet (too many carrots) and see if you can get help with this.