Just below the surface of your skin, across most of your body, lie tiny sebaceous glands that produce an oily substance called sebum.

Your face, neck, shoulders, chest, and back tend to contain more sebaceous glands than other parts of the body. The palms of your hands and the soles of your feet contain few, if any, sebaceous glands.

Sebum tends to rise to the surface through pores around your hair follicles. Sebum helps lubricate and protect your skin, essentially waterproofing it.

When your glands are producing just the right amount of sebum, your skin looks healthy, but not shiny. Too little sebum can lead to dry, cracking skin. Too much sebum in a follicle can cause a hardened plug to form, which can then lead to various forms of acne.

A plug can result from too much sebum production, or dead skin cells that block sebum from reaching the surface.

A sebum plug can look like a tiny bump under the surface of the skin or it may stick out through the skin like a grain of sand.

When a sebum plug forms, bacteria that normally lives harmlessly on the surface of your skin can start to grow within the follicle. Inflammation follows, causing a breakout.

Sebum plugs commonly form on the forehead and chin. And because nose pores tend to be large, when they become even partially clogged, plugs can be even more noticeable.

Plugs can also appear on your upper arms, upper back, or just about anywhere you have hair follicles. Sebum plugs tend to be precursors for blackheads and whiteheads.

Here are the most common types of skin plugs:

Blackheads

When a sebum plug only partially blocks a hair follicle, it’s known as a blackhead or a comedo. It appears black because the air changes the color of your sebum. It’s not dirt.

Whiteheads

If a sebum plug completely blocks a hair follicle, it’s known as a whitehead. The plug remains under the skin, but produces a white bump.

Keratin plugs

Keratin plugs can look like sebum plugs at first. However, this skin condition develops differently and tends to cause patches of bumpy skin.

Keratin, which lines hair follicles, is a type of protein that helps protect the skin from infection. It’s not clear why it builds up and forms a plug, though there may be a genetic component.

Other types of acne

When a sebum plug becomes inflamed, a papule can form. It’s a small pink bump on the skin that can be tender to the touch.

A papule can turn into a pus-filled lesion called a pustule or pimple. Pimples usually have a red base. A larger painful pustule is called a cyst and requires the care of a dermatologist, a doctor who specializes in skin health.

When sebum builds up inside a sebaceous gland, the gland can expand, causing a small, shiny bump to form on the skin. This is called sebaceous hyperplasia, and it occurs most often on the face. Unlike most other types of acne, which primarily affect teens and young adults, sebaceous hyperplasia is more common in adults.

All types of acne start with plugged pores. To help prevent the buildup of oil and dead skin in your pores, wash your face with soap and water every day. Use a mild face cleanser and keep the rest of your body clean, too, especially areas that may be prone to acne.

Exfoliate

If you have a sebum plug of some kind, gently exfoliating dead skin cells may help keep the acne from worsening. To do this:

  1. Wet your face with warm water.
  2. Apply exfoliating scrub gently for about a minute.
  3. Rinse with warm water and softly pat your skin to dry.

Use topicals

Daily topical treatments, such as glycolic and salicylic acid ointments, may do the job. Other nonprescription treatments, such as benzoyl peroxide, that kill bacteria may be helpful.

A class of topical medications called retinoids, which are derivatives of vitamin A, might be recommended. Tretinoin may be better for oily skin and skin that can tolerate a strong medication. Retinol is usually recommended for more sensitive skin.

When it comes to any topical treatment, you want to look for products labeled “noncomedogenic” or “nonacnegenic,” because they won’t cause more pore clogging. Severe acne may need a powerful prescription antibiotic, such as tetracycline or erythromycin.

Shop for over-the-counter acne medication and face wash.

Try oral medication

Severe acne that can’t be treated with topical medications may need oral drugs, such as isotretinoin. This reduces the size of the sebaceous glands to cut sebum production, and increases how much skin you shed.

While isotretinoin can be very effective, it’s a powerful medication with some serious potential side effects. Pregnant women shouldn’t take it, as it may lead to birth defects. Another side effect is depression. Anyone taking the drug should be carefully monitored by a doctor.

Do…

  • consult a dermatologist or aesthetician about your acne
  • seek out a professional skin care expert to use an extraction device to remove a sebum plug
  • be aware that if a plug is extracted, the remaining pore may look hollow
  • exfoliate to make pores look less noticeable

Don’t…

  • pick at a sebum plug
  • try to remove a plug on your own
  • ignore the fact that if you do try to remove one, it could lead to infection and scarring

If good skin hygiene, over-the-counter cleansers, and lifestyle changes aren’t improving your skin, you should see a dermatologist. It’s always better to see a doctor earlier than later when it comes to any type of skin problem.

Acne can get out of control quickly. Even if you only have a few clogged pores, it’s worth seeing a doctor for guidance and a prescription cleanser if needed.

The nature of your skin condition and any other symptoms will help guide your doctor’s treatment plan. You may be prescribed a topical ointment and given instructions about a daily skin care regimen.

If the condition is serious, your doctor may prescribe an antibiotic or other oral medication right away.

When sebum plugs, blackheads, whiteheads, or any other related skin condition is visible — particularly on your face — it may make you feel self-conscious.

The buildup of sebum in your pores isn’t necessarily the result of anything you’re doing or not doing. Your genetic makeup may be why your skin is oiler than average.

Keep in mind that there are many types of effective treatments on the market. Talk with a dermatologist or a skin care specialist about the best options for you.

Healthline and our partners may receive a portion of revenues if you make a purchase using a link above.