Hair follicles are small structures contained within the skin. All the hair on your face, body, and head grows from hair follicles. Blocked hair follicles are pimple-like bumps that form under the skin. They may be red in color, and painful.

When hair follicles become blocked in areas of the body containing sweat and oil glands, they can turn into hidradenitis suppurativa, a chronic skin condition. Hidradenitis suppurativa is also known as acne inversa. This condition affects areas of the body that sweat and have skin folds.

In this article, we explain why blocked hair follicles occur and how you can prevent and treat them.

Blocked hair follicles aren’t caused by poor hygiene. They’re also not contagious. The trigger that causes blocked hair follicles to form is not completely understood.

It’s thought that blocked hair follicles form through this process:

  1. Hair follicles become clogged with keratin, a naturally occurring protein found in hair, skin, and nails.
  2. The clogged hair follicle traps sweat inside.
  3. The clogged hair follicle fills with bacteria, which breed and grow.
  4. The clogged hair follicle filled with bacteria expands and ruptures.
  5. A painful pimple or swollen lump filled with pus forms under the skin.
  6. Bacteria from the burst follicle spreads, causing more follicles to become blocked and more pimples to form.

Certain risk factors may make you more susceptible to getting blocked hair follicles. They include:

  • being assigned female at birth
  • having a health condition that causes insulin resistance or a hormonal imbalance, such as polycystic ovarian syndrome (PCOS)
  • having psoriasis
  • being Black, Hispanic, or biracial
  • having a family history of hidradenitis suppurativa
  • having excess weight
  • smoking cigarettes
Illustration of healthy hair follicles and blocked hair folliclesShare on Pinterest
Healthy hair shaft versus blocked and inflamed hair shaft. Illustration by Wenzdai Figueroa

Blocked hair follicles generally form in areas of the body that contain sweat glands and have skin folds, such as:

  • armpits
  • under the breasts
  • groin and inner thighs
  • buttocks

Blocked hair follicles range in severity from mild to severe. They start out looking like small and irritated red pimples. Over time, they may look like pus-filled lumps, cysts, or boils. They may abscess and drain pus and blood.

Blocked hair follicles can be painful, especially if boils form deep under the skin. They may also itch.

Your skin may feel irritated and sore, especially when pimples and cysts form in areas that rub together and cause friction.

As the condition progresses, you may see black dots that look like blackheads, often in pairs.

If abscesses form and leak, you may notice an unpleasant odor.

Hidradenitis suppurativa is a chronic condition that may come and go over time. The lumps caused by blocked hair follicles can become connected by tunnels under the skin. These tunnels may leak pus or blood.

Scar tissue can form as part of the healing process. Eventually, the scar tissue may thicken and appear red.

Over time, areas of skin, such as your underarms or groin, may be filled with widespread lumps and significant amounts of thickened scar tissue.

The tunnels and thickened scar tissue can cause chronic pain and inhibit movement of the arms or legs.

Mild hidradenitis suppurativa can resemble folliculitis, a common skin condition.

A dermatologist can help determine which condition you have. It’s important to seek medical help if you get a rash, pimples, or boils that don’t resolve, or that reoccur. Early or ongoing treatment can help prevent complications.

If you have blocked hair follicles, try these at-home tips:

  • Wear loose, nonrestrictive clothing that lets your skin breathe.
  • Wash the area with antibacterial soap.
  • Don’t squeeze or pop any pimples or boils.
  • Use warm water compresses to treat painful lumps; you can also use a black tea bag to make a warm compress
  • Keep your skin dry and cool, and try to limit sweating.
  • Don’t wax the area or do anything that might irritate skin. If you must shave, wash the area first with antibacterial soap, protect your skin with gel shaving foam, and use a fresh blade.
  • Don’t use deodorants containing alcohol, parabens, baking soda, dyes, fragrance, or other harsh ingredients.

Treatments for mild or moderate cases of blocked hair follicles include:

  • topical and oral antibiotics
  • benzoyl peroxide acne medication body wash
  • anti-inflammatory medications
  • steroids
  • pain medications
  • oral isotretinoin
  • Humira, a biologic medication that’s approved by the Food and Drug Administration for this use

Severe hidradenitis suppurativa may require surgery, to remove scar tissue and deep lumps.

It can be challenging to eliminate blocked hair follicles completely. However, these strategies may help:

  • The American Academy of Dermatology says 70 to 90 percent of people with hidradenitis suppurativa smoke cigarettes. If you try to stop or limit smoking, you may reduce flareups or even eliminate this condition completely.
  • Maintaining a moderate weight and reducing sugar in your diet can help. Try cutting out simple carbohydrates, such as desserts, white bread, and white potatoes.
  • Laser hair removal may be beneficial.
  • Stress may exacerbate this condition. Stress-relieving activities, such as exercise, meditation, and yoga, may help.
  • When you exercise, try to stay cool. If your clothing becomes damp and sweaty, change into dry clothes quickly.

What’s the difference between a blocked hair follicle and folliculitis?

A blocked hair follicle is part of a chronic, inflammatory skin condition. It can be treated and often prevented, but it has no cure.

Folliculitis is inflammation or infection of hair follicles. It’s often self-resolving but can become chronic.

Folliculitis is more common than hidradenitis suppurativa. Both folliculitis and mild hidradenitis suppurativa may respond to similar medical treatments.

Are blocked hair follicles contagious?

No. Blocked hair follicles are not contagious. You will not get this condition from touching or coming into contact with someone who has it.

Are blocked hair follicles caused by poor hygiene?

No. The exact cause of blocked hair follicles is unknown. Hygiene does not play a role. In fact, doctors recommend not scrubbing the skin when cleaning it if you have this condition.

Does diet affect blocked hair follicles?

It may. There appears to be a link between insulin resistance and blocked hair follicles. Reducing your simple carbohydrate intake may help reduce or eliminate flareups.

Being overweight may also be a risk factor. Maintaining a moderate weight and eating a balanced diet may help.

If I have this condition, will it definitely cause scarring and become unsightly?

No. It can be challenging to treat blocked hair follicles, but early treatment can help to significantly reduce the severity of this condition.

Find a doctor you trust, and do whatever you can to reduce your personal risk. If you smoke cigarettes, try to quit.

Blocked hair follicles occur when the hair shafts in your skin become clogged.

Blocked hair follicles that occur in areas where the skin rubs together — such as the groin or armpits — can turn into a chronic skin condition known as hidradenitis suppurativa. This condition can cause painful lumps and scarring.

Early diagnosis and treatment can help reduce the severity and potential complications of this condition. See a doctor if you have a rash or pimples that don’t resolve.