Skin with acne vulgaris

What Is Acne Vulgaris? (Hint: You've Probably Had It at Some Point)

Everything you need to know about the most common skin condition in the world.


5 minute read

Acne vulgaris: it’s a complicated-sounding name for the world’s most common skin condition. The term acne has Latin origins, based on the Greek word akné (interestingly, thought to be an ancient misprint of akmé). As for vulgaris, it’s also Latin, meaning common or ordinary. So acne vulgaris is simply the most common, or typical, variety of acne.

In case you missed it, we’ve already explained how to figure out what type of acne you have. But if you’re interested in delving a little deeper into the condition of acne vulgaris, let’s get a little scientific. After all, the more you know about your healthy skin journey, the better equipped you’ll be to cope with a few bumps along the way.


What is acne vulgaris?

Technically speaking, acne vulgaris is an inflammatory disorder of the pilosebaceous unit — aka the pore. Each pore contains a:

  • Hair follicle: specialized cells that produce hair proteins
  • Arrector pili muscle: responsible for making hair stand on end
  • Sebaceous gland: produce sebum that’s excreted into the pore

Essentially, acne vulgaris arises when the delicate balance of form and function within the pilosebaceous unit goes awry. This results in a skin response that shakes out in two ways:

  • Non-inflammatory acne: when pores clog with dead skin and sebum, causing blackheads and whiteheads
  • Inflammatory acne: bacteria flourishes in the pore, triggering inflammation and sometimes, follicle breakdown, leading to papules, pustules, nodules and cysts.

What causes acne vulgaris?

While no one’s exactly sure how it happens, Dr. Sandra Lee (aka Dr. Pimple Popper) says dermatologists have a pretty good idea that acne forms as the result of an imbalance involving:

  • Sebum: skin’s natural oil, triggered by androgen hormones during puberty
  • Keratin: a sticky, tough protein that strengthens skin, hair and nails
  • Bacteria: a microbe known as C. acnes (formerly called P. acnes)

One of the most significant mysteries is whether these variables all lead to acne — or whether acne itself creates some of the physiological changes demonstrated in the research. Let’s take a closer look at what some of the latest science says about the roles these factors play in acne formation.


The issue of excess oil is often oversimplified when it comes to acne. Yes, it’s true that people with acne-prone skin typically produce more sebum — but it’s also perfectly possible to have oily skin and not have acne. So researchers have been focusing on not just the amount of sebum produced, but also the individual compounds it contains, including:

  • Triglycerides
  • Wax esters
  • Squalene
  • Cholesterol esters
  • Cholesterol
  • Free fatty acids

Turns out, the composition of sebum in acne patients is noticeably different from that of acne-free patients. Research is ongoing, but some evidence points to the idea that these alterations may damage skin barrier function, create oxidative stress, and provoke inflammation that predisposes a person to acne.


Cells that produce keratin are called keratinocytes — and they make up the bulk of our epidermal layer. You might recall that as keratinocytes are pushed to the skin’s surface, they flatten and toughen into corneocytes, which are held together by stringy proteins called desmosomes.

Researchers have observed that in acne patients, the epidermal lining of pores undergoes hyperkeratinization: too much keratin accumulates and causes clogs. They’ve found a couple of different keratinocyte abnormalities that causes this:

  • Buildup of dead cells: instead of sloughing off as expected, the desmosomes hang onto dead skin longer
  • Overproduction of cells: the skin cells lining the follicles actually reproduce faster than normal

The net net: too much keratin inside the pore narrows the opening to the skin’s surface, eventually causing a clog. Again, there’s a bit of a chicken-or-the-egg debate over what triggers hyperkeratinization in the first place: it could be a genetic difference, or it could be caused by one of the other factors (like excess sebum or bacteria).


First, some housekeeping: if you’ve been paying close attention, you may have noticed that we’ve always referred to the microbe associated with breakouts as P. acnes — short for Propionibacterium acnes. There are many varieties of propionibacterium, including one that’s responsible for creating the holes in Swiss cheese.

In order to better differentiate these organisms, the type of propionibacterium that’s found on skin was recently reclassified as Cutibacterium acnesC. acnes, for short. If you’re into reading skincare research, you’ll probably notice both terms used in the scientific literature — and hear Dr. Lee use them interchangeably.

The latest research suggests that, like excess sebum, C. acnes is a key factor — rather than a direct cause — of acne formation. Case in point: C. acnes is present on virtually everyone’s skin — regardless of whether acne is present.

Scientists believe that it’s likely the specific terrain, or native environment, that makes a person susceptible to acne-causing bacteria. For example, C. acnes may take advantage of a compromised skin barrier, or a disruption in the skin’s microbiome, allowing it to upset the delicate balance and leading to an inflammatory response.

How do you treat acne vulgaris?

Acne — especially this common variety, can affect virtually all age groups and demographics, though it’s most common in adolescents, due to fluctuating hormones. But whether it’s teen acne, or an adult version like hormonal or menopausal acne, the proper treatment depends on the type of pimples present.

Non-inflammatory acne benefits from exfoliants that can penetrate into pores to prevent clogs. Dr. Lee’s favorites from SLMD Skincare include:

Inflammatory acne is best treated with antimicrobial ingredients that can help tame the immune response as well. Two of the most effective are:

Retinoids are also highly effective for treating all forms of acne vulgaris, because they speed up cell turnover, making it less likely for dead skin to stick around and plug up pores. SLMD Retinol Resurfacing Serum has a gentle, time-release formula. It’s part of the 3-step Acne System, which helps manage acne at every stage — and also includes a non-comedogenic moisturizer to protect the skin barrier.

For acne-prone skin that’s also sensitive to benzoyl peroxide, try the Sensitive Skin Acne System, which features sulfur instead.

Dr Sandra Lee

Dr. Lee's Last Word

Though there are many different types of acne, by far the most prevalent is acne vulgaris. Whether we’re treating blackheads and whiteheads, or those inflamed, red pimples that may have a white center, we have a variety of dermatological ingredients that are very effective. I always suggest that patients start with consistent skincare, like my SLMD Acne System. Don’t pop your pimples — and don’t forget to show your skin kindness and patience!


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