What Are Blocked Hair Follicles?

Reviewed by Brunilda Nazario, MD on October 15, 2020

If your hair follicles get blocked in areas where you also have many oil and sweat glands, you may first notice them as pimple-like bumps on your skin. They may be in places where you normally don’t have breakouts. Over time they can become painful or maybe get infected and turn into scars.

The condition is also called hidradenitis suppurativa (HS) or acne inversa. It happens when the shafts where hair grows out of your skin, called follicles, get blocked.

There’s no cure for the condition, but treatments can make flares happen less often. A healthy lifestyle can help a lot, too.

What Causes Blocked Hair Follicles?

Why Diagnosis Is HardIt's important to treat hidradenitis suppurativa early, but some symptoms mimic other diseases. Here’s what to look out for.105

ROOPAL BHATT: With hidradenitis,

we now consider it to be

a disease of the hair follicles.

So just like any other disease

process, an ounce of prevention

is always worth a pound of cure.

So HS typically appears on body


Underarms are probably

the number one area.

They can also occur on groin

folds as well, sometimes

the upper inner thighs,

between the buttocks area,

underneath the breasts

in women as well,

sometimes in the back

of the neck.

Severe cases, you can get it

on the genital area.

The fact is that there are

a few things that can mimic HS.

Many times patients do confuse

their symptoms

for another disease.

And it is almost

like a bad acne, something

called a blackhead

or a comedone.

One thing that can mimic

early hidradenitis is something

called boils.

Because hidradenitis affects

the younger population,

they may not, of course,

have the medical awareness

to know that hey,

this can represent something

more than just a cyst or a boil

or something that's going to go


There is definitely

a psychosocial element

of hidradenitis as well.

They feel embarrassed.

Or they just feel that maybe

they'll be judged, because they

will assume that other people

think that this is either

a contagious disorder

or something that they caused

because of poor hygiene.

And of course, that's not

the case at all.

Most people can't necessarily


But I think people now are

becoming a lot more cognizant

of their bodies and their skin,

and they're able to go

to the physician to get

that diagnosis.

Whenever the skin is telling

you, hey, look at me,

this is not normal,

we do recommend for patients

to seek their dermatologist

or their primary care physician

to kind of get that process

started being treated.

Roopal Bhatt, MD, dermatologist<br>U.S. Dermatology Partners, Austin, TX/delivery/53/ea/53eacbb9-5b69-4ac5-b1e7-ba63cca56192/vd-1123-diagnosing-hs_,1000k,750k,4500k,2500k,400k,.mp412/01/2017 12:00:00650350doctor examining man/webmd/consumer_assets/site_images/article_thumbnails/video/why_diagnosis_is_hard_hs_video/650x350_why_diagnosis_is_hard_hs_video.jpg091e9c5e81888d79

Doctors don’t know for sure. Many think hormones might play a role, since the condition usually hits after puberty and breakouts can flare for women around the time they have their periods. The problem is three times more common for women than for men.

It may also happen because of your immune system. Most people get clogged hair follicles from time to time, but if you have HS, your body may be overreacting to those blockages.


Your genes may make a difference, too. One-third of people who have the condition are related to someone else who has it.

Doctors know what doesn’t cause the condition:

  • It doesn’t happen because you don’t wash yourself well enough.
  • You can’t catch the disease from someone else.

Other things can trigger breakouts:

  • Smoking
  • Being overweight
  • For women, getting your period
  • Hormone changes
  • Heat
  • Sweating


What Are the Symptoms?

At first, blocked hair follicles usually look like breakouts of pimples or boils. They usually form in places where your skin rubs together, like your armpits or groin.

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woman showering

If you’re a woman, you’re more likely to have them on your genitals, upper thighs, or under your breasts. For a man, they happen more on your genitals and around your anus. The bumps may come and go or just stay the same. You might get them in the same spot every time, or they might move around your body.


If your condition gets worse, you may have:

  • Deep breakouts that hurt
  • Bumps that burst, and maybe leak fluid that smells bad
  • Scars after your breakouts heal. They may get thicker over time.
  • Skin that looks spongy because of deep lines called tracts
  • Infections
  • In rare cases, skin cancer

Your symptoms might change quickly, so blocked hair follicles can look different at different times. One week you might have bumps leaking fluid, and the next, the area may be cleared up.

Once you start to notice these breakouts, see your doctor as soon as you can to start tackling the problem. You can get treatments that can help clear your skin and maybe prevent more breakouts and complications.

WebMD Medical Reference



American Academy of Dermatology: “Hidradenitis Suppurativa.”

American Academy of Family Physicians: “Hidradenitis Suppurativa.”

National Organization of Rare Disorders: “Hidradenitis Suppurativa.”

Genetic and Rare Diseases Information Center: “Hidradenitis Suppurativa.”

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