Milia form when tiny plugs of a skin protein called keratin get trapped just beneath the surface of your skin, creating small, firm white or yellowish bumps. Each milium is essentially a miniature cyst: a pocket lined with skin cells that fills with the same tough protein your body uses to build hair and nails. Unlike whiteheads, these bumps aren’t filled with oil or bacteria, which is why squeezing them doesn’t work.
What Happens Inside Your Skin
Your skin constantly sheds dead cells and replaces them with new ones. Normally, old cells flake off the surface without you noticing. Milia develop when this shedding process stalls in a specific spot, usually around a tiny hair follicle.
The cyst typically originates at the lower part of a fine “vellus” hair follicle, right where the oil gland connects. Vellus hairs are the nearly invisible peach-fuzz hairs covering most of your face. When the narrow channel of that follicle becomes obstructed, dead skin cells can’t escape to the surface. Instead, they accumulate into a compact ball of keratin, walled off by several layers of skin tissue. Under a microscope, this wall looks like a scaled-down version of your outer skin, complete with the same cell layers you’d find on the surface.
Recent research suggests these cysts may originate from the outermost cells of the hair bulge, a region of the follicle’s outer root sheath. The specific proteins expressed in the cyst wall match the proteins found in that part of the follicle, pointing to it as the likely starting point.
Primary Milia vs. Secondary Milia
Dermatologists split milia into two categories based on what triggers them. The distinction matters because it determines whether the bumps are a standalone skin quirk or a sign of something else going on.
Primary Milia
Primary milia appear spontaneously, without any obvious injury or underlying condition. They arise from the vellus hair follicle itself, forming at the junction where the oil duct meets the follicle channel. These are the milia you see on newborns’ noses and cheeks, and they’re also the most common type in adults. On adult skin, they favor the face, especially the area around the eyes, cheeks, and forehead. Primary milia in newborns are extremely common and typically resolve on their own within a few weeks as the baby’s skin matures.
Secondary Milia
Secondary milia form after something damages or disrupts the skin. Unlike primary milia, which come from hair follicles, secondary milia more often originate from sweat ducts, though they can also develop from any skin structure, including oil glands and the outer layer of skin itself. They can appear anywhere on the body, not just the face.
Known triggers include burns, dermabrasion, radiotherapy, blistering skin diseases, and prolonged use of topical steroids. Even isotretinoin (a strong acne medication) has been reported to cause eruptive milia as a rare side effect, possibly by altering the way follicles process keratin. The bumps look identical to primary milia under a microscope. The only real difference is their origin story.
Why Adults Get Milia on Their Face
Beyond skin trauma, everyday skincare habits play a bigger role than most people realize. Heavy occlusive ingredients can disrupt your skin’s natural shedding cycle by forming a seal over the surface. When dead cells can’t slough off normally, keratin builds up and gets trapped.
Common culprits include petroleum jelly, mineral oil, lanolin, beeswax, paraffin, and rich natural butters like cocoa and shea butter. Even dimethicone (a silicone found in many foundations and primers) can contribute to congestion when layered thickly. The risk goes up in hot, humid climates where your skin is already producing more oil and sweat.
Specific habits that set the stage: overusing thick eye creams around the delicate periorbital skin, sleeping in makeup, or layering multiple occlusive products without giving your skin a chance to breathe. Sun damage also thickens the outer layer of skin over time, making it harder for dead cells to exit through follicle openings. This is one reason milia appear more frequently in older women and on chronically sun-exposed areas of the face.
How Milia Differ From Other Bumps
Milia are easy to confuse with several other skin conditions, but a few characteristics set them apart. A milium is firm, dome-shaped, and typically 1 to 2 millimeters across. It’s white or pale yellow, doesn’t have a visible opening or pore at the center, and doesn’t respond to squeezing. There’s no redness or inflammation around it unless you’ve been picking at it.
Whiteheads (closed comedones) look similar but feel softer and contain a mix of oil and dead cells inside a pore. They respond to acne treatments. Syringomas, another common look-alike, are small sweat gland growths that tend to appear in clusters, especially under the eyes. They’re typically skin-colored or slightly yellow and are firmer than whiteheads but slightly flatter than milia. Sebaceous hyperplasia bumps have a characteristic doughnut shape with a central dip, and they’re caused by enlarged oil glands rather than trapped keratin.
How Milia Are Removed
Milia don’t have an opening to the skin’s surface, which is why they don’t respond to squeezing or to acne products designed to unclog pores. If left alone, some milia eventually resolve as the cyst wall breaks down and the keratin is reabsorbed. This can take weeks to months, and some persist indefinitely.
Professional removal is straightforward. A dermatologist nicks the top of the cyst with a small blade or a bent hypodermic needle, then applies gentle lateral pressure with a comedone extractor to pop the tiny keratin ball out intact. The procedure takes seconds per bump and usually doesn’t require numbing. For multiple milia, mild electrocautery (a tool that uses a tiny electrical current to break down the cyst) is another option.
Attempting extraction at home risks scarring, infection, and incomplete removal, especially around the eyes where the skin is thin and delicate.
Preventing New Milia From Forming
Since milia form when keratin gets trapped under the skin, prevention centers on keeping your skin’s natural cell turnover running smoothly. Gentle chemical exfoliation is the most practical approach. Look for cleansers or leave-on treatments containing salicylic acid, glycolic acid, or citric acid. These help dissolve the bonds between dead cells so they shed before they can accumulate in follicles.
Topical retinoids are another effective option. They speed up cell turnover and change the way keratin is produced in the follicle lining, making it less likely to clump and obstruct the channel. Retinoids are available in both prescription and over-the-counter strengths.
On the product side, evaluate whether your moisturizer or eye cream is heavier than your skin actually needs. If you’re prone to milia, swap occlusive formulas for lighter, water-based alternatives. Remove makeup thoroughly every night, paying extra attention to the under-eye area where product tends to migrate and settle into fine lines. In humid weather, lighter layering across your entire routine reduces the chance of trapping keratin beneath a film of product.