What Are Blocked Hair Follicles?

Medically Reviewed by Brunilda Nazario, MD on October 20, 2021
2 min read

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.

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


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.

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.