Milium refers to small, firm, white or yellow cysts that form just under the surface of the skin, usually 1–3 millimeters in diameter. They most commonly appear on the face, especially around the eyelids, cheeks, and forehead. Dermatology literature classifies them as keratin-filled cysts formed when dead skin cells become trapped within tiny skin structures.
Why Does a Milium Form?
The formation of a milium is rooted in the skin's natural exfoliation process, or turnover. In healthy skin, a new cell is generated in the basal layer of the epidermis and migrates upward, eventually shedding off as a dead keratinocyte. A milium occurs when this turnover process malfunctions. Instead of sloughing off, the dead skin flake and keratin protein become trapped beneath the surface, hardening into a small cystic ball.
Dermatology research categorizes milium as primary or secondary. Primary milium develops spontaneously. It is common in newborns as their skin continues to mature, and in adults it may result from slow exfoliation or thickened epidermis. Secondary milium appears after skin damage. Burns, blistering disorders, laser treatments, dermabrasion, and chronic sun exposure can disrupt normal keratinization. During healing, trapped keratin can form small cysts.
How Is a Milium Diagnosed?
Although milium resembles acne to non-specialists, its biology is entirely different. Acne results from clogged follicles, inflammation, and bacterial activity, often with comedones, papules, pustules, redness, or tenderness. Milium is not inflammatory. It appears as hard, dome-shaped cysts that remain stable in size. They do not become painful or produce pus, and acne medications that target sebum and bacteria do not help.
In a case where the diagnosis is ambiguous, or to distinguish a milium from another similar-looking condition like syringomas or epidermoid cysts, enhanced visualization may be necessary. This is where dermoscopy plays a vital role.
A dermoscope is a handheld device that provides magnification and illumination, allowing the observer to see the subsurface skin structure. For thorough self-examination or preliminary assessment by a skincare professional, high-quality optical magnification is essential. A device such as the IBOOLO dermatoscope can be utilized to obtain a clear, magnified view of the skin's surface.
Who Is More Likely to Develop Milium?
Milium can occur in all age groups, but certain factors increase the likelihood of development. Infants commonly develop primary milium, which typically resolves within several weeks as the skin matures. Adults with chronic sun exposure may also be at higher risk due to long-term thickening of the skin.
People with certain blistering diseases, such as epidermolysis bullosa or porphyria cutanea tarda, may develop secondary milium more frequently. Dermatologic procedures that disrupt the epidermis, including laser resurfacing or chemical peels, can also promote formation.
Can a Milium Be Removed Safely?
While the neonatal milium requires no intervention and resolves naturally, a persistent milium in an adult often requires physical extraction if removal is desired for a cosmetic reason. The golden rule of management is to avoid squeezing. Because the cyst is encased in a capsule of skin with no opening, squeezing only ruptures the surrounding soft tissue, leading to infection and hyperpigmentation.
The standard medical treatment is "deroofing." A dermatologist or licensed aesthetician uses a sterile needle or a lancet to create a tiny incision in the epidermis directly over the cyst. This creates an exit route. Once the "roof" of the skin is opened, a comedone extractor or sterile forceps is used to gently apply pressure, causing the hard keratin pearl to pop out cleanly. This procedure causes minimal discomfort and heals rapidly, usually without scarring.
For a patient with widespread or multiple occurrences of the milium, an alternative treatment may be employed. A topical retinoid is frequently prescribed. The retinoid functions by increasing the rate of cell turnover and reducing the "stickiness" of the keratinocyte, which can help bring the cyst to the surface over time and prevent a new one from forming. However, a topical treatment is generally slower acting than physical extraction.
In a more resistant case, particularly with milia en plaque, therapy such as cryotherapy, electrodesiccation), or laser ablation may be utilized to destroy the cyst wall and evacuate the content.
What Is the Prognosis?
The milium is a benign lesion with no malignant potential. It does not pose a health risk but can be a source of cosmetic distress. For the neonate, the prognosis is excellent, with complete resolution being the norm. For the adult, while the condition can be chronic, it is highly responsive to treatment. Recurrence is possible, particularly if the underlying cause—such as the use of an occlusive product or lack of exfoliation—is not addressed. However, with a combination of professional extraction and a scientifically sound skincare regimen, the skin can remain clear and smooth.