Why does milia occur?

What is trapped under the skin?

Skin normally sheds old cells as new ones replace them. When old cells remain trapped beneath new skin, they can harden into small cysts. These are milia: tiny white or pearly bumps just below the surface, not acne or whiteheads.2

Milia are superficial cysts rather than large, deep lumps. They commonly cluster on the upper cheeks and around the eyes, although the face and scalp are not their only possible locations.3

Why do adults get milia?

Primary milia develop in children and adults, often around the eyelids, cheeks and forehead. Secondary milia develop after damage to the skin. Traumatic milia appear at the injured site as skin heals and can arise from sweat ducts, including after burns, dermabrasion or blistering rashes.4

Inflamed or injured areas can also develop milia. Clothing or rough bedding can irritate existing bumps and cause redness around them while the centre stays white. That irritation does not turn milia into acne.5

Can creams or medicines cause milia?

Some secondary milia form as a reaction to a heavy skin cream or ointment. Long term use of steroid creams is another possible cause. Certain topical medicines, including hydroquinone and corticosteroids, can rarely be followed by milia. Medicines that suppress the immune system are also associated with secondary milia. Do not use a prescribed steroid for longer than your clinician directs.124

There is no reliable way to prevent all milia, which gives the skincare aisle less to sell under the heading of prevention. Avoiding excessive sun exposure and further skin trauma can reduce the risk of some secondary forms. Less commonly, milia are associated with inherited disorders or other skin diseases.245

Why do newborn babies get milia?

Almost half of newborn babies develop milia. The same trapping of keratin causes these cysts, usually on the nose or elsewhere on the face. Similar cysts inside a newborn's mouth also disappear on their own. Newborn milia do not usually need treatment, and adult lotions or oils should not be used on a baby's delicate skin.125

How long do milia last?

Newborn milia usually clear within a few weeks, although some take months. Primary milia in older children and adults can clear within weeks or persist for months or longer. Ordinary milia are harmless and generally do not hurt or itch; some rarer forms can be itchy or appear in groups on a raised patch.124

What should you do about milia?

Treatment is optional when milia are only a cosmetic concern, even if the skincare aisle would prefer a longer shopping list. A clinician can open a cyst with a sterile instrument and remove its contents. For widespread milia, topical retinoids, medicines applied to the skin, may help.14

Do not squeeze, scrape or pierce milia at home: this can cause infection or permanent scarring. Wash gently each day and pat dry. See a clinician if the bumps worsen, bother you or have not improved after a few months. For a newborn, a coloured rash or crusting around the bumps is a reason to seek medical advice.12