Acne Causes
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When one of those massive, red, and super painful pimples erupts on my skin, the first I think about is how I can make it disappear as quickly as possible. Then, I usually fixate on exactly what caused that acne breakout to happen in the first place. Is it my diet? Are my hormones to blame? To make the journey to clear skin a little easier, I reached out to two skincare professionals for an explainer on some of the most common causes of acne.

Excess Oil Production + Sticky Cells

The oil that your skin produces is a huge culprit in the formation of acne, but for a few different overlapping reasons. One of the most common is its play in clogging the pores. "Our skin is made out of thousands of pipes connecting oil glands to the surface of the skin," Dr. Joshua Zeichner, a board-certified dermatologist in New York City, says. "As oil is produced and makes its way through the follicle, it may become trapped behind sticky skin cells, accumulating, leading to a pimple."

How much oil you produce, he explains is all in your genetic code, and is largely influenced by your hormones. "This explains why women tend to break out so cyclically every month when they get their period," he notes.

Overgrowth of Bacteria + Inflammation

We all have bacteria living on our skin, but an overgrowth of this bacteria can lead to inflammation, which results in red, inflamed breakouts. "Acne is an inflammatory condition, not an infection, even though bacteria on the skin are involved in its development," Dr. Zeichner says. "The bacteria promote inflammation, rather than causing a true infection."

But how does the bacteria balance get out of whack? Sometimes, it's oil's fault. "The skin naturally produces oil or sebum (more so during puberty) and this acts as 'food' for the bacteria normally living on our skin," Dr. Karan Sra, a board-certified dermatologist, explains. "The overgrowth of this bacteria can lead to acne, as can clogging of pores with sebum."

This explains why some people take prescribed oral antibiotics to help clear up their acne.

Dr. Joshua Zeichner also says that some people with acne tend to just have a higher concentration of bacteria on their skin and can react to it more.


There's a few different hormones that can cause acne to pop up at the worst time possible. Two of the big ones are testosterone and cortisol. Both of these stimulate oil production, explains Dr. Sra, which can lead to inflammation and clogged pores.

"For women, hormonal acne tends to manifest as red, cystic lesions on the lower part of the face (cheeks, jawline, and neck)," she says.

Cortisol, as you know, is the hormone associated with stress. While Dr. Sra says that stress acne is essentially hormonal acne, its treatment does vary slightly.

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"There is data to suggest that your diet can affect acne," Dr. Zeichner says. Dairy is one of the most-blamed food groups when it comes to breakouts, particularly cow's milk. The idea is that it contains sugar and hormones that could play a part in excess oil production and therefore the formation of acne.

Foods with a high-glycemic index are also commonly blamed. "High levels of sugar in the blood promote skin inflammation, leading to blockages of the pores," Dr. Zeichner says.

However, when it comes to acne, your safest bet is going to a board-certified dermatologist and letting them analyze your symptoms to decide what's actually causing your acne. From there, they can direct you on the best treatment to clear it up.