What are these dry, white patches on my back, chest, and/or arms?

 This is called “tinea veriscolor”. It is a yeast type of skin fungus present on normal ski, similar to
 dandruff. This is very common and harmless. The “white patches” usually are not noticeable until
 you start tanning because they do not tan. An over-the-counter treatment may be used, however, it
 is always best to consult your dermatologist.