Milia form when dead skin cells that would normally shed from the surface get trapped in a tiny pocket just beneath the top layer of skin. These small, white, dome-shaped bumps are filled with keratin, the same protein that makes up your hair and nails. They’re not acne, they’re not caused by bacteria, and they can’t be popped like a pimple. Understanding the specific reasons they show up on your skin can help you prevent new ones from forming.
How Milia Actually Form
Your skin constantly produces new cells and sheds old ones. When that shedding process gets disrupted, dead cells can become enclosed in a small cyst just below the epidermis. The trapped material is almost entirely keratin, which hardens into a firm, pearly bump typically 1 to 2 millimeters wide. Unlike whiteheads, milia don’t form inside pores. They sit under a thin layer of intact skin, which is why squeezing them does nothing but irritate the area.
There are two broad categories. Primary milia arise spontaneously from the tiny hair follicles that cover your face. Secondary milia develop after something damages the skin and disrupts its normal turnover cycle. The triggers, locations, and persistence differ between the two, but the end result looks the same.
Primary Milia: The Kind That Shows Up on Its Own
Primary milia are the most common type and typically appear on the cheeks, eyelids, forehead, and nose. They develop without any obvious trigger. Your skin simply fails to shed a small cluster of dead cells, and a cyst forms. This can happen at any age, including at birth.
In newborns, milia are extremely common, affecting up to 50 percent of babies. They usually disappear on their own within the first month of life, though some persist into the second or third month. No treatment is needed. In adults, primary milia tend to be more stubborn and rarely resolve without some form of intervention.
Secondary Milia: Damage-Related Triggers
When milia appear after an identifiable event, they’re classified as secondary or traumatic milia. The skin’s repair process can trap keratin beneath new tissue as it heals. Common triggers include:
- Burns, including sunburns severe enough to blister
- Blistering skin conditions like contact dermatitis, shingles, or autoimmune blistering diseases
- Skin procedures such as dermabrasion, laser resurfacing, or aggressive chemical peels
- Chronic sun exposure, which thickens the outer layer of skin and slows natural cell shedding
Secondary milia sometimes resolve on their own, but they tend to persist longer than primary milia. They can also appear in unusual locations, wherever the original skin injury occurred rather than the typical cheeks-and-eyelids pattern.
Why Sun Damage Is a Major Factor
Cumulative UV exposure is one of the most overlooked reasons adults develop milia later in life. Years of sun exposure thickens and toughens the skin’s outermost layer, making it harder for dead cells to slough off naturally. This is why milia often cluster on sun-exposed areas like the cheeks, temples, and around the eyes in middle-aged and older adults. Consistent sunscreen use and limiting prolonged sun exposure are among the simplest ways to reduce your risk.
Skincare Products That Trap Dead Cells
Heavy, occlusive skincare ingredients can create a physical seal over the skin that prevents dead cells from shedding normally. The main culprits are petrolatum, mineral oil, lanolin, and thick synthetic waxes. Heavy botanical oils applied generously overnight can also contribute, especially around the delicate eye area where the skin is thinnest and milia are most likely to form.
This doesn’t mean you need to avoid moisturizers entirely. The issue is layering dense, film-forming products in milia-prone areas. If you notice new bumps after switching to a richer eye cream or night balm, the product itself may be trapping keratin beneath the surface. Switching to a lighter, non-occlusive formula is often enough to stop new milia from forming.
Rare Genetic Connections
In uncommon cases, widespread or persistent milia in children or young adults can signal a genetic skin disorder. Conditions like Bazex-Dupré-Christol syndrome, basal cell nevus syndrome, and Gardner syndrome all include milia as a characteristic feature. These conditions come with other recognizable signs and are diagnosed early in life. If you’re an otherwise healthy adult with a few milia on your face, a genetic cause is extremely unlikely.
Why You Can’t Pop Them at Home
Because milia sit under a sealed layer of skin rather than inside an open pore, there’s no path for the contents to escape when you squeeze. Attempting to extract them at home with your fingers or unsterilized tools risks scarring, infection, and inflammation without actually removing the cyst. The keratin plug is firm and enclosed, not soft and ready to drain like an acne lesion.
How Milia Are Removed
For milia that bother you cosmetically, a dermatologist can remove them in a quick office visit. The most common approach involves nicking the surface of the bump with a sterile blade, then gently pressing or using fine forceps to express the intact cyst through the tiny opening. The whole process takes seconds per bump and typically heals without scarring.
For larger numbers of milia, other options include electrocautery (using a tiny electrical current to destroy the cyst) and laser therapy. These are less commonly needed but work well for stubborn or widespread cases.
Preventing New Milia From Forming
Since milia result from trapped dead skin cells, the most effective prevention strategy is keeping your skin’s natural exfoliation process on track. Over-the-counter cleansers and treatments containing salicylic acid, glycolic acid, or citric acid help clear dead cells from the surface before they can become trapped. Using these consistently on milia-prone areas makes a noticeable difference over time.
Prescription retinoid creams are a step up in effectiveness. Retinoids, which are vitamin A derivatives, speed up skin cell turnover and loosen existing keratin plugs, helping them migrate to the surface and resolve. They also thin the outermost layer of skin just enough to prevent new pockets from forming. If you get milia repeatedly, a retinoid may be worth discussing with a dermatologist.
Beyond active treatments, the basics matter: wear sunscreen daily to prevent the skin thickening that comes with UV damage, and avoid piling heavy occlusive products around your eyes and cheeks. These two habits alone address the most common preventable causes of milia in adults.