Acne sucks. What sucks even more is that it seemingly targets some of our most visible body parts: Our face, our chest and our upper back (so fun during beach season!) Why is that, though? It’s not like those areas are any more dirty or sweaty than our feet, which don’t sprout any zits at all. According to dermatologist Lisa Chipps, it’s all about the location of the oil-producing glands on your body.
“The areas of the skin that contain the highest number of pilosebaceous units—which are structures that contain both a hair follicle and a sebaceous oil gland—are the areas where we’re most prone to acne [the face, the chest and the upper back],” Chipps explains. “When bacterial growth and inflammation occur within that structure, it manifests itself in the form of a pimple.”
Why we evolved with all our pilosebaceous units concentrated in these areas remains one of the body’s many mysteries. One theory is that because these structures are responsible for sprouting hair and producing sebum (aka oil)—both of which are tools the body uses to protect and hydrate the skin—it only seems right that they’d be condensed in areas that are most susceptible to the sun, especially back before T-shirts or sunblock were a thing.
Whether this theory is correct or not, our pimple-producing glands aren’t migrating to less visible areas any time soon. But that doesn’t mean your face, chest and upper back have to be covered in zits forever: If you’re still experiencing acne even as an adult, check out our dermatologist-approved tips on how to fight it. You’ll be friends with the mirror again in no time.