Acne can emerge at the most inopportune times, in the most annoying places.

Pimples most commonly pop up on your forehead or nose — but the face is far from the only place breakouts are possible.

Bumps are sometimes found in awkward areas such as the armpits, scalp and even your butt. Treatment varies according to where the inflammation is present, and sometimes, what appears to be acne at first glance may not even be acne at all.

“People don’t realize acne needs a specific kind of hair follicle to form, and those follicles aren’t everywhere,” said board-certified dermatologist Dr. Christina Marcelus, MD, MS, FAAD. “So when someone tells me they have acne in their armpit or on the sole of their foot, my first job isn’t to treat the acne. It’s to figure out what it actually is, because it usually isn’t acne.

We broke down where on the body it’s actually possible for pimples to emerge, and when you may need to take a second look or see a doctor — plus, the best acne treatment to stash in your bathroom cabinet for those unexpected flare-ups.

Is acne on the bikini line possible?

If you’ve ever noticed small bumps on your bikini line after hair removal, chances are the culprit is simply an ingrown hair.

“Shaving, waxing, and epilating traumatize the follicle, and the hair curls back into the skin — that’s an ingrown hair, not a pimple,” said Dr. Marcelus. “Tight synthetic underwear and long stretches in damp workout clothes make it worse by trapping heat and friction.”

The first line of defense is changing out of your wet clothes the second you’re done with a workout to avoid any bacterial build-up in nether areas. Then, adopt a body wash or pad with salicylic acid, which target follicular plugging and ingrown hairs.

Salicylic acid is the key ingredient in this formula, which also includes three essential ceramides to hydrate and restore the skin’s natural barrier. It targets sensitive skin without harsh beads that scrape or further irritate the area.

Beat post-bikini wax irritation with these salicylic acid-infused pads, which are specially made to treat razor bumps and ingrown hairs. They’re safe enough to use on sensitive skin, so you don’t have to worry about further irritation.

The product is also formulated with glycolic acid to gently exfoliate and witch hazel to soothe.

Use this leave-on body exfoliant all over or as a spot treatment for uneven texture. Make sure to always follow with SPF during the daytime, especially if used on the arms and legs, which are exposed to UV rays.

Is scalp acne possible?

The short answer is yes, since the scalp has oil glands. However, Dr. Marcelus noted that most scalp bumps are folliculitis (a skin condition where hair follicles are inflamed or infected), and a good amount are caused by yeast, not bacteria. It’s an important distinction to make, because some antibiotics used for bacterial issues can actually make folliculitis worse.

Heavy pomades, dry shampoo and sweating under hats can all aggravate scalp bumps as well.

Dr. Marcelus recommended ketoconazole or zinc pyrithione shampoo for the scalp (and even chest/back bumps) if yeast is suspected. Leave on a few minutes before rinsing to let the product fully go to work.

Formulated with 1% zinc pyrithione, this shampoo not only keeps your scalp clean and protected, but it also fights against dandruff. The ingredient stays on your scalp for up to 72 hours and is safe enough to use daily.

The brand notes that dandruff is caused by malassezia yeast deep in the scalp, and this hair product tackles it at the root.

Ketoconazole kills scalp fungus, fights bacteria and reduces inflammation. Not only does this shampoo ease redness, but it also controls flaking and itching from dandruff.

The product is safe to use on color treated, chemically processed and gray hair.

Is butt acne possible?

According to Dr. Marcelus, red bumps on your backside are rarely true acne and are usually folliculitis.

“The buttocks spend the day compressed against a chair, under occlusive fabric, frequently damp — that’s a mechanical problem more than a hormonal one,” she pointed out. “Sitting in sweaty leggings or a wet swimsuit is a real driver.”

Folliculitis can be caused by either bacteria or yeast. In the case of the former, a chlorhexidine wash is a great start for treatment.

Sometimes, those butt bumps could be keratosis pilaris, a condition caused by a build-up of keratin that clogs hair follicles. Dr. Marcelus shouted out urea or lactic acid lotion to alleviate the rough, bumpy texture of keratosis pilaris on the butt and thighs.

Chlorhexidine gluconate (CHG) kills germs, bacteria and fungi upon contact. The dermatologist-recommended formula can be used as both a soap or skin cleanser to put bacteria at bay.

Formulated with 12% lactic acid, this multitasker lotion exfoliates, hydrates and protects the skin without harsh scrubbing. Eliminate any worries of further irritation: The product is cruelty-free, dye-free, paraben-free, phthalate-free and fragrance-free.

Rough, bumpy skin gets a boost of hydration thanks to this non-sticky lotion with 10% urea, which exfoliates and moisturizes. Plus, shea butter sourced from Burkina Faso restores the skin’s hydrolipidic film, an invisible layer that keeps your dermis healthy.

Is armpit acne possible?

“True acne is very uncommon here, because the armpit isn’t rich in the oil-producing follicles acne requires,” Dr. Marcelus explained.

Instead, the bumps you are seeing may be due to irritation from shaving or folliculitis. Harsh ingredients (i.e. fragrances) in your deodorant or antiperspirant ingredients can also cause irritation that looks acne-like.

Dr. Marcelus urged people to watch out for hidradenitis suppurativa in this area, a chronic skin condition caused by blocked hair follicles.

“If you get painful lumps that come back in the same spot in the armpits, groin, under the breasts, or between the buttocks, and especially if they drain on their own or leave rope-like scars, that is very likely not acne,” she explained of the skin disorder, which roughly affects 1 in 100 people.

“Patients wait years for a correct diagnosis, often being told repeatedly that they have boils or an infection. It’s not an infection, it’s not contagious, and it has nothing to do with hygiene: It’s an inflammatory condition, and there are now FDA-approved treatments for it.”

If you suspect you may have hidradenitis suppurativa, seek treatment from a doctor.

How to treat acne with lifestyle shifts (especially in awkward areas)

• Change out of wet clothes immediately after your workouts to avoid bacteria or yeast build-up
• Wear breathable fabrics over tight synthetics
• Don’t scrub the area too hard. Excess exfoliation of an inflamed follicle can aggravate the issue
• Shower after sweating
• Don’t sit in a wet swimsuit
• Shave with the grain, use a fresh blade and ditch multi-blade razors
• Don’t apply full-strength facial acne products to skin folds. “Concentrations that a cheek tolerates fine will cause a painful irritant dermatitis in the groin or armpit,” per Dr. Marcelus

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