Acne and the Microbiome: Christi Investigates

Christine Preston is back to share more microbiome research insights with us. Thanks Christi!

Hi again, everyone!

This week I’ve been battling some nasty skin flare-ups, and it occurred to me that I didn’t really know what types of bacteria cause or contribute to acne.

There is a multi-billion dollar industry trying to sell washes, creams, medications, and makeup to the acne-prone masses(1). I figured there must be some fascinating research about the relationship between my skin microbiome and the zits currently erupting on it.

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It turns out that there is a LOT of research on acne, and at least one bacteria, Propionibacterium acnes, is involved. However P. acnes is one of those bacteria that is always found on human skin, regardless of how flawless or pimply your skin looks.

P. acnes is an unusual bug. It happens to be the only bacteria that can live in our skin follicle glands (the places where zits are made), consuming the oily sebum made there. Researchers think acne has a LOT to do with how much sebum is produced in our follicles -which is related to diet, genetics, and hormones-, and how our individual immune systems react to the P. acnes growing in our skin follicles(2).

In other words, those bacteria-laden, pus-filled pimples you *absolutely never* pop may have a lot more to do with your parents (Thanks Dad!), and your diet (quesadillas are awesome!), than the bacteria that hangs out in them. And here I was hoping for a quick solution that didn’t involve my quesadillas! Intriguingly, it turns out there are some fascinating differences in the skin microbiomes of acne-prone and non-prone people.

One group looked at the bacteria species in skin follicles of acne and non-acne prone people(3). Overall, P. acnes was the dominant species found in everyone’s follicles. However, in non-acne skin it was the only species found. Acne-prone skin was different. A lot of the acne-prone people had multiple bacterial species hanging out at low frequencies in their follicles! The actual bacteria species varied, but a lot of the acne-prone people had small levels of Staphylococcus epidermidis in their follicles, with Corynebacterium tuberculostearicum Actinobacterium, Staphylococcus hominis hominis. Anaerococcus, and Pripionibacterium granulosum all found in at least one acne prone person.

Another group from UCLA looked very closely at the genetics of P. acnes in the skin of acne-prone and non-prone people(4). They found that the overall level of P. acnes on the skin of the two groups was comparable, however the strains (the subspecies groupings) were different. Acne-prone skin had different P. acnes strain compositions than the non-prone skin. This demonstrates genetic differences in the P. acnes that grown on acne-prone versus non-prone skin.

Unfortunately neither of these studies shows that bacteria differences cause acne, or suggest quick fixes for the acne-prone. I’m very glad this research is being done, and I’m excited to see more results from further studies! In the meantime I’m running a completely uncontrolled study on whether yoga and broccoli help clear up my skin.