system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What causes the various types of acne?

I've always been told that acne is caused by dirt entering the pores. If this is true, why are there so many different types. There are white heads and black heads which look totally different. There are also those types that form below the surface of the skin that you are not able to pop. What is causing these? They certainly all can't be from the same source. Is the skin excreting some type of oils under the skin? Or is it at all tied into the blood stream?

EDIT: Also, hour does it relate to your diet?
gpt
All of them are caused by various bacterial infections blocking pores, followed by white blood cells trying to kill the infection piling up and natural oil getting stuck. Whiteheads are still covered by skin, while blackheads have broken the surface slightly and oxidized.