The most common cause of white spots or stripes is pressure points. These are caused from lack of oxygen to these areas of skin. For example, many people find they have pressure points on the back of their hips where their lower back touches the acrylic. The easiest way to reduce the lines is to move! People who lie very still or sleep while tanning are prone to pressure points. Even if you don’t flip or change positions it is recommended that you slightly move around while in the tanning bed. Other causes for white spots are genetic. Sometimes there are certain patches of your skin that simply is not efficient at producing melanin and therefore you won’t develop a tan in these areas. For example, Vitiligo is characterized by irregularly shaped white patches that are surrounded by a darker border. These white patches are very sensitive to sunlight. You should consult a doctor for treatment. Another common cause is a fungus, Tinea vesicolor. This fungus begins in your hair much like dandruff, and can fall down onto the skin on your upper body. This results in white spots that are unable to produce melanin. Sometimes the spots may be scaly. This fungus is very treatable, although it can take up to a few months to rid. Tinea vesicolor is not a result of tanning, however it becomes apparent after tanning since color will not develop in these areas.