Milia are small white or yellowish cysts that can appear anywhere on your face — including on your eyelids or under your eyes. Milia can occur elsewhere on your body as well. They are sometimes called milk spots or oil seeds and tend to occur in clusters.

Milia are very common among newborns. In fact, nearly half of full-term newborn babies have at least some facial milia. But milia can also affect teens and adults.

In most cases, milia do not become infected. But they are a cosmetic concern that most people want removed.

The singular form of milia is milium.

Milia occur when dead skin cells or keratins (proteins found in skin and hair) get trapped within the base of a hair follicle or sweat gland. This causes a small raised bump that looks a tiny pimple or whitehead.

What causes milia to occur is not fully understood. Milia are not acne, which is usually triggered by hormones and causes inflammation.

Sun damage to skin is a risk factor for milia. Too much sun makes skin rough and leathery, so it's more difficult for dead cells to rise to the skin's surface and shed normally.

Milia are also associated with skin damage from injuries, medication or illness. These less-common forms are called secondary milia.

Sometimes, milia disappear without treatment. But they also can be persistent unless steps are taken to remove them.

Milia often will disappear over time without treatment. A type of milia that affects newborns (neonatal milia) usually goes away within a few weeks.

Milia affecting older children and adults often last longer. Many people seek treatment of long-lasting milia for cosmetic reasons.

Milia on eyelids and under eyes often are persistent. These should be removed by a dermatologist or an ophthalmologist who specializes in cosmetic eye surgery.

Procedures used for milia treatment include:

• Chemical peels
• Laser ablation
• Cryotherapy (freezing)
• Diathermy (heat therapy)

Sometimes, it's safe to remove milia occurring away from the eyes at home with a sterilized needle, lancet or comedone extractor.

SEE ALSO: What a bump on the eyelid called a chalazion looks like

Comedones — also called blackheads and whiteheads — are the primary signs of acne.

A comedone extractor is a hand-held, pencil-shaped skin care tool. It usually has a sharp lancet on one end and a small looped or spoon-shaped extractor on the other end.

Comedone extractors are used to open and express the contents of pimples, acne lesions and milia. Be sure to clean and disinfect a comedone extractor with isopropyl alcohol before and after each use.

Do not attempt to remove milia on your eyelids or under your eyes at home with a comedone extractor. Treatment of milia near your eyes should only be performed by a medical professional.

If you have persistent milia on your eyelids or near your eyes, see an eye doctor to discuss the best (and safest) treatment options.

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