…we still have no clue.
After scouring the research from the last several years regarding sebum (skin oil), acne bacteria, gene transcription, and a bunch of other super techie stuff, the answer to what causes acne is…um…we still have absolutely no idea. Most diseases are tricky things, and acne is no exception. Scientists are really only still scratching the surface when it comes to nailing down what actually happens that starts the acne ball rolling.
Let’s take acne bacteria for instance. Over the past few years, scientists have located more strains of P. Acnes, the bacteria present in human skin. We don’t know which strains might be harmful and which might actually be helpful. Furthermore, we don’t know which of the secretions of which of the bacteria strains cause problems and why. Additionally, we don’t know if it’s the secretions that cause a problem or if certain strains of bacteria interact with cells in some other way, such as interacting with cell RNA, toll-like receptors, or inflammation. And, um…if these bacteria do interact with skin cells in some way, we don’t know whether it’s dermal cells, oil cells, or immune/inflammatory cells.
The story is equally muddled when you look at the immune response of the skin, the inflammatory cascade, cell signaling, et cetera, et cetera.
Regardless, it’s not all bad news. Some directions of inquiry are starting to look more interesting than others. For instance, scientists are starting to frame acne as an inflammatory disease and are focusing in on how to mediate the body’s inflammatory response in the skin.
With time, we may be able to better specify what causes acne, which could theoretically lead to a cure. Rest assured that I’ll keep on top of the latest research. In the meantime, The Regimen should work well to keep acne under complete control, and in more severe cases, Accutane is an option as well.

The more I learn about antibiotic therapy for acne, the more wary and less enthused I become. Due to overuse and misuse over the past twenty years, antibiotic resistance has become widespread throughout the skin of the world population. This is evidenced by the increasing ineffectiveness of both oral and topical antibiotics in clinical studies. Antibiotics never worked very well for acne, and now they work even less well.
If your doctor has you on antibiotic therapy for acne and nothing else, it may be time to have a talk with her/him. The authors of the expert opinion review also note that topical antibiotics should be used for no longer than 3 months and oral antibiotics for no longer than 6 months. So, if you have been on antibiotic therapy for a long time, it may also be time for an appointment with your dermatologist. Since poor compliance with antibiotic regimens are one of the main causes of antibiotic resistance, just make sure you do not stop antibiotic therapy on your own without consulting with your physician first.