Although doctors aren't certain why acne occurs, they do know some key factors that make a person more acne-prone [source: American Academy of Dermatology]. As we mentioned previously, hormones can be a big cause of acne. When puberty hits, a teenager's androgenic hormones, which include estrogen or testosterone, can go into overdrive and cause the sebaceous glands to pump out excess sebum. The follicles can't handle it all, so clogged pores result. Adult women may also experience breakouts during hormonal changes that occur just before their menstrual cycle begins.
Heredity may also be a factor in how acne affects you. If one or both of your parents had acne, you're at a greater risk for inheriting the triggers that cause overproduction of sebum and lead to clogged follicles [source: Fulton].
Environmental and situational factors may also trigger a condition called acne mechanica, in which acne occurs on areas of the body where the skin's more susceptible to aggravation by heat, pressure or friction. Pollution and high humidity can also be factors in back acne because they create the perfect conditions for clogged pores and breakouts.
If you participate in sports, you can get acne mechanica along your hairline from wearing a helmet. Tight uniforms that put a lot of pressure on the skin can also be a cause of acne mechanica. But athletes aren't the only ones prone to this condition. Musicians who play string instruments can develop acne around the chin area from having to hold their instruments underneath their chins.
From these examples, it's easy to understand how acne mechanica can manifest itself on a person's back. Students toting around heavy backpacks can develop acne on their backs from the pressure of the straps. People who work outside in hot weather can develop acne from too-tight clothing. People who drive a lot can be prone to back acne from the pressure of the seat on their backs.
Some people believe that stress or certain foods, such as chocolate or fried food, play a role in acne development. However, scientists have not discovered anything to prove these myths correct [source: Mayo Foundation for Medical Education and Research].
Now that we know a little more behind the causes of back acne, let's take a look at how you can control it.