3 Signs Your Acne Is Actually Hidradenitis Suppurativa (HS)

Knowing the difference could impact your skin care routine.

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Pimples and cysts plague most people at some point in their lives, so it’s easy to shrug off your bumpy skin as the acne curse. However, if you’re faced with severe skin problems that seem like more than a stubborn zit, you may not realize that what you might think is a just bad case of garden-variety acne (acne vulgaris) is actually a less well-known form called hidradenitis suppurativa (acne inversa).

“Hidradenitis suppurativa is an inflammatory condition that sometimes may resemble acne,” says Hirshel Kahn, MD, a dermatologist at The Mount Sinai Hospital. “They are both conditions of hair follicles getting clogged up by cells and [oil] which comes off the surface of the skin.” Learn more about what hidradenitis suppurativa is here.

Both conditions are are triggered during puberty and hormone fluctuations, and tend to be more common in women. Here’s how to find out if it’s HS or acne.

1. Location, location, location

While there are some regions on the body that HS and acne share, like the chest and buttocks, most of the time HS lesions appear in places that everyday acne does not. HS is more likely than other kinds of acne to develop in creases of the body: the armpits, groin, breast, and thighs, according to the American Academy of Dermatology. And as you’re probably well aware, acne most commonly pops up on the face, back, neck, shoulders, and upper arms.

2. Severity and pain

Acne can be painful (especially when your skin is irritated from rubbing or picking), but it’s usually not as severe as pain from HS. The pimple-like bumps in HS can grow very deep into the skin, and the pain can be debilitating and significantly affect a patient’s quality of life.

On a 0-10 pain scale, patients with HS typically rated their pain in the range 4–10 and described it as burning, stretching, splitting, throbbing, and aching, according to a 2014 study in Postgraduate Medical Journal.

3. Pus problems

Besides a little white pus if you squeeze a whitehead (don’t do it!), most acne doesn’t typically involve significant leakage. (Psst… Here’s why you shouldn’t squeeze a pimple.)

HS lesions, on the other hand, often leak a bloody or foul-smelling pus that can stain clothing—without your even squeezing or irritating the bumps.

If you notice new developments on your skin—whether you think it’s acne, HS, or something else—it’s important to have a dermatologist evaluate it. A dermatologist’s trained eye can notice the subtle but obvious differences between acne, HS, or other skin conditions.

And this distinction matters: HS is treated differently than acne. Your derm may prescribe antibiotics, steroid shots, or biologic drugs for severe cases of HS, according to Dr. Kahn. Treatment for HS is important and should be done as early as possible to prevent it from worsening and leaving permanent scars.