There are several reasons why white spots become noticeable on the body once the tanning process begins: patches of skin, which do not tan, could be the result of genetic determination. White spots could also appear due to the presence of a fungus, which lives on the skin’s surface. While the fungus is harmless, it does absorb UV light, which would normally penetrate the skin. This fungus did not appear as a result of tanning; it merely becomes noticeable once tanning occurs. It can be remedied through the use of prescription drugs or topical lotions. White patches of skin, which are often prominent on the shoulder blades and just above the buttocks, can be caused by pressure from the body as it reclines on a hard tanning bed surface. This pressure inhibits the flow of blood through that area of skin. Since blood carries oxygen, which is essential to the tanning process, this area does not tan. Periodic body shifting during tanning will make these patches disappear. Certain medications can react unfavorable with exposure to UV light.