When we were teenagers, acne was a part of life — it was hard to tell where one breakout ended and another one began. It was brutal, sure, but we were all in it together (85% of teens get acne, according to the American Academy of Dermatology). Plus, there was some solace to be found in knowing that the pimple parade was merely a teenage rite of passage.

Except it wasn’t. Sure, there are a few of us out there admiring our pristine, blemish-free adult faces 24/7 in every reflective surface we pass. But most of us deal with the occasional breakout — and plenty deal with way more than that. A 2012 study of almost 3,000 women found that 45% of women aged 21–30, 26% of women aged 31–40, and 12% of women aged 41–50 had clinical acne.

So if acne isn’t merely a teenage affliction, what is it?

The basics work like this: our sebaceous glands produce an oily substance called sebum. When all is working well, that sebum makes its way from the sebaceous gland, up the follicle it’s connected to, and out onto the skin via the opening of the follicle, aka a pore. When things go wrong — like when extra sebum, skin flakes, or makeup clogs those pores — sebum gets trapped in the hair follicle, and bacteria “propionibacterium acnes” that normally lives on the skin, grows in the plugged follicles instead, causing inflammation and pimples. The result? An emergency trip to the drugstore for concealer.

The good news? Where you put that concealer can tell you a lot about what’s causing the breakouts in the first place, especially if you keep getting pimples in the same places.

You can start by taking a look at the places on your body that get rubbed up against often. If you get acne wherever your bra straps, bike helmet, scarf, winter hat, and other tight clothing makes regular contact with your skin, your problem may have a pretty easy solution. Known as acne mechanica, breakouts in these spots are basically caused by heat and friction — so they’re easy to start treating by removing the source of friction, no acne cream needed!

Hormonal acne can also be easy to spot based on where it flares up — namely, the chin, mouth, and jawline.

Hormonal acne can also be easy to spot based on where it flares up — namely, the chin, mouth, and jawline. Male hormones (which are actually present in both men and women) called androgens are largely to blame, since even at normal levels, they can overstimulate the oil glands and alter the development of cells that line hair follicles in the skin, the American Academy of Dermatology explains. Excess facial or body hair, a deepening voice, or irregular or infrequent menstrual periods are other signs your chin, mouth, and jawline acne could be hormonal. This type of breakout can sometimes be a doozy to treat — and it can cause painful, cystic bumps in the meantime — so get yourself to a doc if you suspect hormonal acne.

If it’s not hormonal and you’re also seeing spots on your nose and forehead in addition to your chin, then you’re looking at a possible oily T-Zone issue. “The T-Zone is chock full of oil glands, and anything that sets off oil production can cause a breakout,” says Dr. Jessie Cheung, Director of the Jessie Cheung MD Dermatology & Laser Center in Willowbrook, IL. “Stress is probably the biggest cause of T-Zone breakouts,” she adds. “When you’re stressed, your body releases more of the stress hormone, cortisol, which translates to excess oil production. Another trigger is eating a lot of highly processed carbohydrates — think white breads and sugary pop.” Treatment can start at the drugstore — just pick up a product with salicylic acid to loosen up the oil in the clogged pores. Still seeing red? That’s when your dermatologist may suggest retinoids, birth control, or spironolactone to control the hormonal fluctuations that might be contributing to the breakouts, says Dr. Cheung.

Zits dotting your hairline — and only your hairline? Look up: your scalp may be to blame. “Hairline breakouts are usually triggered by products meant for the scalp, that wind up getting onto your facial skin,” says Dr. Cheung. “Styling gels, shampoos, hydrating conditioners, and even de-frizzing products may have emollient ingredients that clog your pores.” That goes double for those of you working out with a head full of texturizing spray. “Sweating does help to trap the oil, dead skin, and bacteria in your pores to trigger hairline breakouts,” Dr. Cheung says. “It’s best to keep your hair off your face, and wash your face and hair after exercising. Swap out your pillowcase as often as possible — some of my patients have tried pillowcases impregnated with silver, a natural antibiotic!”

Remember, acne is a complicated beast, and the wrong products can make things even worse. If you’re using a drugstore product to treat your acne and haven’t seen any improvement in a couple of months, move on and head to your dermatologist for proper diagnosis and treatment. After all, you may not have left zits behind in your teens, but that doesn’t mean you have to be stuck with them for good.

Diana Vilibert is a freelance writer and copywriter living in Brooklyn, NY. She loves flea markets, martinis, to-do lists, traveling, and wearing leggings as pants. You can see more of her writing at www.dianavilibert.com and follow her on Twitter at @dianavilibert.