We talk to a derm about what's really behind the pimples that crop up well beyond our teen years

Think you left those pesky pimples behind in your teenage years? Think again. It's not uncommon for acne to pop up again — or appear for the first time! — later in life. According to the Canadian Dermatology Association, acne affects 20 to 30 per cent of adults aged 20 to 40. Fighting acne and fine lines and wrinkles?! Life is so unfair.

So what's causing it? Unfortunately, there isn't one specific cause. "There are so many different factors that play a role in why we break out and where we break out," says Lindsay Barras, education manager at skin care company Dermalogica Canada. She explains that hormones, stress and certain lifestyle factors can all play a role.

While the cause of adult acne is definitely multifactorial, Dr. Lisa Kellett, a Toronto dermatologist and owner of DLK on Avenue, says she often sees women with acne that's been caused by the products they're using on their skin. "When patients first come to see me, we do a product review," she says. "Adult women with acne should avoid heavy creams, lotions and oils."

If the acne is significant, Dr. Kellett says she will look at a patient's full medical history and at other symptoms that might indicate an underlying health condition. In some cases, acne can be indeed be related to hormones, she says. For example, some adult women who have acne also have polycystic ovary syndrome.

Regular monthly hormone fluctuations can also trigger breakouts. This "cyclical acne" shows up before your period, or it might flare up during pregnancy or menopause, and may help explain why adult acne overwhelmingly affects women: The Canadian Dermatology Association reports that 75 per cent of adult acne occurs in women.

When it comes to stress, says Dr. Kellett, it doesn't cause acne — but it can make it worse. And between work obligations, bill payments, family life and a busy social calendar, it's no surprise that Canadian adults report their stress levels peaking between the ages of 35 to 49. "Stress causes an increase in oil production," she explains. "When someone is stressed, they might also pick at their skin, which can make acne worse."

And as for the theory that our occasional salty, fried, rich or junk food indulgences are causing our acne, there's no strong evidence to support that claim, says Dr. Kellett. "But what I do tell patients is that they should have a good balanced diet with lots of vegetables. If you have the odd piece of chocolate, that's not going to cause acne; but if you eat chocolate every day, that could definitely have an impact."

So, what's the best way to treat adult acne? Dr. Kellett says gel-based products will ensure you're still getting moisture, but they usually won't break you out. She also often recommends topical benzoyl peroxide and exfoliating cleansers.

For persistent or severe cases of adult acne, Dr. Kellett recommends seeing a dermatologist, who might suggest you try an in-office treatment. "Blue-light therapy and epidermal peels are helpful," she says. "For cystic acne, we [may] do something like photodynamic therapy."

Luckily one of the best anti-aging ingredients out there — regular ol' retinol, perhaps already the star of some of your products at home — also happens to be an effective treatment for some blemishes. "If you have comedonal acne [like blackheads and whiteheads], retinol can be helpful," says Dr. Kellett.