Where there is lots of sebum, there is a fertile home for acne vulgaris, the most common form of acne. Your face, upper back, shoulder and upper chest have more sebaceous follicles than other parts of your body, making these areas targets for acne. More than eight out of 10 people will become acquainted in their lifetimes with acne vulgaris [source: Harper].
There's not one single factor that can take all the blame for acne vulgaris. The following all seem to play a part:
- Excessive cell division in the follicles. Researchers point to this as the first trigger of acne, but they aren't entirely sure what causes the skin cells to go bonkers and multiply. Androgen hormones likely play a part. When you get too many cells all trying to exit through the same narrow follicle, it means only one thing: a breakout.
- Too much sebum. When we hit puberty, our bodies crank up the hormone production, as well as the sensitivity to those hormones. This in turn kicks sebum production into overdrive.
- Bacteria. Specifically, bacteria known as Propionibacterium acnes, or P. acnes for short. This bacteria can often be found in acne lesions (there are different types of lesions, which we'll discuss in a moment). This bacteria leads to our fourth cause of acne vulgaris: inflammation.
- Inflammation. When skin cells and sebum jam up a follicle, bacteria shows up and then you get inflammation. Talk about making a bad scene even worse. Now, instead of just having a follicle backed up, the blockage is flaring outward, sensitive or even painful to the touch and unsightly.