Acne: Types, Causes, Scarring, Treatment

Common acne, referred to medically as acne vulgaris, is a condition that the vast majority of us have to go through at one point or another in our lives.

Some of us are fortunate enough to only experience a mild, temporary case during puberty, but many others aren’t so lucky. In fact, acne is the single most common skincare issue seen by dermatologists.

What Is Acne?

Though there are a variety of different kinds of acne, in general it is described medically as a localized skin inflammation resulting from overproduction of oil by the glands at the base of specialized hair follicles.

These special oil glands are found just under the skin. Once active, they continuously produce and secrete “sebaceous” oils through pores in the skin. Known as “sebum,” the oil both protects and lubricates your skin. However, it is common for these pores to become blocked, leading to a buildup of oil under the skin.

As unpleasant as it might be to think about, we all have bacteria that lives on and in our skin. This bacteria usually keeps to itself, feeding off the sebaceous oil. But if the pore becomes blocked or clogged, the multiplying bacteria have nowhere to go. The surrounding skin becomes inflamed if the follicle breaks.

Different types of acne will then form, depending on how deep into the skin the blockage forms and the nature of the pore’s opening.

Stages of Acne Development

Generally speaking, there are four stages of acne development:

  1. The sebaceous oil glands in the skin are stimulated to begin producing more sebum by androgenic (or male) hormones. Though usually associated with puberty, any changes in hormone levels can cause these glands to begin making more oil.
  2. The pore or follicle is obstructed, either by dead skin or a plug of skin cells and sebum.
  3. Bacteria infects the blockage. The bacteria Propionibacterium acnes and staphylococcus epidermidis are naturally found in hair follicles, but if too many of them build up within a follicle they can start to release an enzyme that breaks down the sebum. This causes inflammation in the follicle.
  4. The follicle ruptures, causing inflammation in the surrounding tissues.

Types of Acne

There are 5 main types of acne blemishes. Whether you suffer from mild acne vulgaris of severe acne rosacea, chances are you’ve experienced several — if not all of them.

Whiteheads (closed comedones)

Aptly named, these blemishes appear with whitish or flesh colored “heads” that are a result of the follicle becoming blocked by sebum (the oil produced by our follicular pores) and dead skin cells. In this case, the blockage is close to the surface, and the pore itself is completely closed off. There is usually very little or no inflammation associated with whiteheads.

Blackheads (open comedones)

Also taking their name from their appearance, blackheads appear as tiny dark or black dots. Similar to whiteheads, this kind of acne is the result of a blockage caused by sebum and dead skin cells. However, the pore remains open, rather than closed. This blemish is caused by the formation of a “plug” forming in the pore opening.

As the material in this plug is exposed to air, it oxidizes, and changes to a darker color. Think about how an apple wedge darkens as it’s left out exposed.

Like whiteheads, this kind of acne does not cause inflammation.


Papules are the phase of acne beyond the whitehead, when sebum, skin cells, and bacteria beneath the skin start to cause irritation and inflammation. These blemishes can be identified by some swelling, redness, and pain, but have no visible pus. They’re usually small to medium in size. Papules are a result of blockages that occur a little deeper in the skin.


Pustules are very similar to papules, except that they contain pus. The classic pimple or “zit,” these tend to be bigger, “uglier” whiteheads. They’re usually painful to the touch, red around the base, and contain whitish or yellowish pus.

Nodules & Cysts

The most severe forms of acne are called nodules and cysts. Both of these are quite large, bigger than either papules or pustules, and appear as painful bumps beneath the skin.Both nodules and cysts can take a long time to fade, and can cause significant scarring. While they’re both located deep within the skin, nodules tend to be hard and not filled with pus, while cysts are filled with pus, and feel like little fluid sacs under the skin.

What Causes Acne?

The two biggest factors to play a role are thought to be genetics and hormones, but other variables like stress, your environment and habits, and diet/medications may also play an important part in the development of acne.


Thought to be the single most important factor in the development of acne, your genetic makeup dictates everything your body does, including how it responds to a buildup of dead skin cells and sebum in a hair follicle.

Once the pore is clogged, one person’s immune system may react by forming a simple blackhead, while another person might develop a red, explosively painful nodule.

Genetics are unpredictable, but at least one study performed on identical twins found that a person’s genes can explain up to 81% of acne prevalence.


While your body’s genetics and immune system reacting to clogged pores is the reason pimples develop, your hormone levels are what cause the blockages in the first place.

As puberty begins, male-associated hormones are produced in the body, and as these hormone levels rise the oil glands beneath the skin enlarge and start producing more sebum, filling the follicle. This can cause some of the surrounding skin cells’ walls to break, creating the perfect home for the P. acnes bacteria to feed and grow.


High levels of stress can trigger or worsen your acne. Your body’s natural response to stress is to release cortisol and male-associated hormones into your system. This in turn increases oil production in the sebaceous glands in your skin.

Some healthcare providers believe that “adult acne” is on the rise because of how hectic modern life has become, with the constant and high levels of stress many people face every day.

Environment and Habits

Although things going on inside your own body are the biggest contributors to acne, external factors like pollution, heat and humidity, and even the products you use can trigger a breakout.

Strong pollutants can cause a rare form of acne called “chloracne,” which is characterized by common acne-like eruptions of blackheads, whiteheads, pustules, and cysts.

The products you use can also play a role. Certain health and beauty products, like makeup, shampoos, pomades, or hair gels and sprays can contribute to blocking pores, leading to acne breakouts on the forehead and along the hairline. Acne that’s caused specifically by makeup is called acne cosmetic. (Look for products with “non-comedogenic” or “non-acneic” labeling to avoid increased risk of breakouts).

Prolonged sun exposure can also have a negative impact, as it increases the rate of cell death and replacement, leading to excess dead skin cells clogging your pores.

A specific, almost exclusive, form of acne at the base of the hairline at the back of the neck of African Americans (usually males) is called Acne Keloidalis Nuchae. It is associated with hard, fixed papules at the base of the hairline that can be treated with similar treatments as most acne types, but can benefit from steroid injections to flatten papules and retinoids to prevent recurrence.

Lastly, acne is often aggravated by friction from hats or sports gear, which can trap bacteria, increase sweating, and inflame the skin.

Diet & Medications

Despite what you may have been taught as a teenager, diet is not a primary cause of acne. That said, there is a growing body of evidence to suggest that in some people, certain foods and medications may play a contributing role in the development of breakouts:

  • Carbohydrates in sugary, starchy, or highly processed foods spike your blood sugar levels, and eventually lead to insulin resistance. Your skin’s response to this is to increase production of a thick, sticky oil into your pores, which, of course, leads to a breakout.
  • Antibiotics and hormones found in dairy products and meat might also add to acne in some people who are especially sensitive to them.
  • High iodine levels found in seafood, seaweed, and iodized salt has also been connected to breakouts.
  • Medications that have side effects that can alter your body’s chemistry or hormone levels can also cause acne breakouts. These include lithium, androgenic steroids, DHEA, progesterone-dominant birth control, and any medications containing bromides or iodides.

Does Acne Go Away After Puberty?

Not always, unfortunately. While acne is most commonly caused by the hormonal changes associated with puberty, it’s a fairly common condition among babies and adults as well. However, an estimated 90 percent of teenagers experience acne, whereas approximately a third of adults suffer from occasional outbreaks.

Baby Acne

Acne can appear as early as birth. This “baby acne” is called acne neonatorum. It’s a fairly common skin condition that affects around 20% of newborns. Usually appearing about two weeks after birth, the blemishes last a few weeks to a few months, though they rarely linger longer than 3 months.

Teen Acne

Acne generally starts around puberty. This is when particular oil glands “wake up” as they are stimulated by male hormones, like testosterone, which are produced in the adrenal glands of both boys and girls.

Most teens are affected by puberty-induced acne to some degree. The hormones associated with all the other changes happening in the body are also responsible for increasing the size and number of sebaceous oil glands in the skin, as well as how much sebum each gland produces.

Adult Acne

30-50% of adults suffer from some form of acne. In some cases, acne that starts in your teen years can continue well into adulthood. However, most sufferers will find that their breakouts go away by the time they’re in their 30s. Severe adult acne can also develop in people who only had mild cases as teenagers.

Acne Treatments

Over-the-counter treatments are often the first step towards an acne solution. Options like benzoyl peroxide, salicylic acid, and alpha hydroxy acids (AHA) are readily available online and in most major drug stores. 

Dermatologists can also offer patients more advanced treatments tailored to their specific needs. These include prescription topicals, isotretinoin, and oral antibiotics.

With such a wide range of options available, the price of acne treatments can vary drastically. Professional treatment options, like photofacials and laser therapy, typically cost approximately $500 per session. At-home treatments, like light chemical peels, are priced between $35 and $70.

How long should You use an over-the-counter acne treatment?

You should always give any new skin care regimen at least 6 to 8 weeks before deciding on how well it’s worked for you. Skin turnover occurs gradually over the course of 28-30 days (much like a female menstrual cycle) – not obviously shedding all at once like a salamander – which in turn requires that more than 4 weeks should be allotted before determining a therapy failure. This doesn’t just refer to OTC acne solutions, but in-office treatments and medications as well.

Is there any treatment that will clear up acne immediately?

Unfortunately, no. Even the fastest therapies will take a few hours, and are only useful for spot treatment. See your doctor to get an idea of your best treatment options. You may be referred to a dermatologist.

Can toothpaste dry up a pimple?

Using toothpaste will not only dry out the pimple, it will dry out and irritate your skin. And as discussed previously, dry/flaky skin only exacerbates acne by providing the clogging material that blocks pores. There are much better products available. Look for a gentle cleanser that is “non-comedogenic” and/or “non-acneic”.

How severe should Your acne be before You see a doctor?

Everyone is different, and visiting a doctor is up to you. A good provider will be able to approach your concerns no matter what severity you present to them at the time of your visit. If you are feeling any kind of physical or emotional distress because of your acne, making an appointment earlier rather than later may be in your best physical (and mental) interest.

Acne Scarring

Scars are usually a result of one of the more severe, inflamed categories of acne, namely papules, pustules, and cysts. As the pore swells due to excess oil, bacteria, and dead skin cells, it can cause a break in the follicle wall. If this happens near the surface of the skin, it’s usually mild and heals quickly.

On the other hand, if it happens deeper in the skin layer, the infected tissue can spill out of the follicle and into the surrounding skin, destroying healthy cells. To repair the damage your skin starts to form new collagen fibers. Unfortunately, for many people, the finished “repaired” skin never looks as smooth and flawless as it was before the breakout.

There are a number of different kinds of scars that can result from acne. They include:

  • Atrophic scars are the most common, and are depressed areas that develop where there is a loss of tissue.
  • Ice pick scars are long, narrow scars that extend deep into the skin (typically the hardest to treat).
  • Boxcar scars are round or oval depressions, giving the skin a pitted look.
  • Rolling scars are fairly broad depressions with rounded, sloping edges. These tend to appear in groups, giving the skin a rolling appearance.
  • Hypertrophic scars are a result of the body producing too much collagen, which creates a visible, raised scar.
  • Keloid scars, or keloids, are similar to hypertrophic scars. The difference is that scar tissue not only expands upward from the surface of the surrounding unaffected skin, but also outward, beyond the borders of the original wound in a “mushroom” like expansion from its original site. This outward expansion can vary greatly and can take weeks to months to form.

Acne hyperpigmentation

Hyperpigmentation commonly refers to the red or dark spots that are often left behind after a pimple heals, but a more clinical term is post-inflammatory hyperpigmentation (PIH). These marks aren’t technically scars, but a discoloration from the prior breakout. Hyperpigmentation can be temporary or permanent.

The best way to reduce hyperpigmentation is to keep newly formed scars covered up from the sun for at least a year. UV exposure can permanently darken scar tissue, however various topical therapies and cosmetic interventions can diminish even some of the most recalcitrant and long-standing hyperpigmentation marks.

The opposite of hyperpigmentation is hypopigmentation, in which a scar lacks natural skin pigment (melanin). This can also be temporary or permanent.

Can acne scarring be prevented?

Usually, yes. In most cases treating the acne itself early will keep all breakouts and healing under control, preventing the formation of scars. However, if your breakouts are severe and associated with painful cysts or nodules, you will be at a higher risk of developing atrophic and/or hyperpigmented scars.

Will acne scars fade over time?

In some cases, yes, especially in the case of hyperpigmentation (dark or red marks), but in many others, the answer is unfortunately no. Depressed, atrophic scars tend to become more visible as we age. This is because as the skin begins to lose collagen, it starts to sag, making acne scars look more pronounced.

What Is The Best Treatment For Acne Scars?

Acne scars can be extremely stubborn, and there is no single treatment that is best for everyone. A few different treatments, or even a combination of them might have the best results to improve tone and texture.

The Bottom Line

To many people, acne and the scars it causes are a source of anxiety and a major blow to self-confidence. Luckily, there are a number of acne treatments that range from simple over the counter topicals — like benzoyl peroxide — to more intensive clinical options — like cortisone shots. 

Those that are left with scars after acne also have multiple treatment options including punch excision surgery, chemical peels, and laser resurfacing. 

It can be difficult to determine which treatment is right for you without the help of a dermatologist or other skin care expert. While one treatment may work wonders on one patient, it may leave another acne sufferer with little improvement. 

Staying positive and seeking out professional help can make all the difference in your treatment journey.