Randy Son of Robert/Flickr

Treating acne is a $3 billion industry in the United States alone. That may be why there's not enormous incentive to develop a vaccine. Like the rest of medicine, though, the approach to acne is now becoming more individualized -- taking into consideration differences in the way different people respond to the disease.

Some acne 101: You may already know that acne is linked to the bacterium Propionibacterium acnes, which nestles in the dark, oily, oxygen-deprived crannies of our pores. Acne is also linked to inflammation, overgrowth of the upper skin layer, excess sebum, and depression. Because the root of the problem has long seemed to be a bacterium, antibiotics have been the go-to treatment. Dermatologists are also working on developing something called "antimicrobial peptides" to kill the bacteria -- anticipating the day that the bacteria outgrow our current antibiotics, and they fail us. 

Still, as millions of people who have used antibiotics in failed attempts know, killing the bacteria doesn't work for everyone. A study earlier this year found that severity of acne does not necessarily correlate with the amount of P. acnes on the skin. It also turns out there are different strains of the bacterium, some of which may cause the more severe cases. It might be too early to say that there are distinct "good" and "bad" strains of the acne bacteria, but it does appear that killing all of them might not be the best plan.

Dr. Jenny Kim, a dermatologist at UCLA, told me that while the "bacterium is involved, everyone has P. acnes on their skin. Whether it's a specific strains of P. acnes, or whether it's an individual's host immune response that's the problem, we're not certain. But recently, people have begun to think that modulating immune response is a better way forward in terms of treatment. The newer trend is to look at anti-inflammatory agents rather than only focusing on the antimicrobial."

One such anti-inflammatory, isotretinoin (better known as Accutane), is a relative of vitamin A. It cleared up my own skin after nearly a decade of severe acne, amazingly. As Kim describes it, "People initially didn't understand how isotretinoin or retinoids worked, but we now know that they can modulate inflammation." Still the drug is not without its issues. It did work a miracle for me, but I also endured months of very dry skin, had to get a number of blood tests, and could not drink alcohol (while in college). Since Michigan's former Representative Bart Stupak's testified before the U.S. House of Representatives Energy and Commerce Committee in 2009 and blamed isotretinoin for the tragic suicide of his 17-year-old son, restrictions on prescribing the drug have become tight.

Studies have since failed to show causation between the drug and suicidal ideation, but current legislation makes it so that dermatologists will often lose money by having it in their practice. 

"It's concerning that that some dermatologists are afraid to use it, so patients go on too long without using it, leading to more life-long scarring," Kim said.

In addition to other retinoids, Kim's lab is seeing promising results with other substances that modulate the immune system, such as vitamin D.

Eighty percent of cases of severe acne can be traced through inheritance from one's parents. The role of diet remains disputed among dermatologists, but the most recent research suggests that different diets can influence the way genes that influence acne are expressed. Meanwhile, the idea of developing a vaccine for acne has been floating around for some time -- as a way to prime your body so that it doesn't react so strongly against the bacteria during the height of a breakout.

Still the fact that acne is a human-only disease makes studying it particularly difficult. We can't recreate it in mice to test vaccines and treatments, or put zits on fruit flies.