Milia: what they are, how to treat them, causes and how long they last

Milia (singular: milium) are small, sub-epidermal cysts containing keratin, the protein that makes up the outer layer of skin. The PCDS says they mainly arise from undeveloped sebaceous (oil) glands and sometimes from sweat glands, and present as small pearly-white bumps just under the skin surface, most commonly around the eyes.

They are very common. In babies they are often called milk spots. A Glasgow neonatal guideline describes newborn milia as yellowish white spots under 2 mm, usually on the face, secondary to blocked sweat glands.

The PCDS says treatment is not necessary and spontaneous disappearance occurs in the majority. For babies, the NHS says milia usually go away within a few weeks and do not need treatment.

In adults who want them removed, the PCDS says the surface can be broken, for example with a sterile needle or the point of a blade, and the contents squeezed out. It adds that careful use of cryotherapy or diathermy can also be effective.

These are procedures for a trained clinician. Opening milia at home with non-sterile tools is not advisable.

Removal for cosmetic reasons is not generally provided on the NHS, so people usually go to private dermatology or aesthetic clinics. Check the practitioner's qualifications and registration, and ask what method is used.

The PCDS groups milia by how they arise. Primary milia are common in newborns and can also arise in children and young adults. Eruptive milia are most commonly seen in young women, perhaps as a sequel to sunbathing.

Milia can also arise as a result of skin damage: mechanical damage such as a burn or dermabrasion, part of a skin condition such as porphyria cutanea tarda and other blistering conditions, or caused by treatment such as chronic steroid-induced thinning of the skin or radiotherapy.

The NHS says milia in young babies usually go away within a few weeks. It says in older children milia might last longer. The PCDS gives no timeframe for adults, saying only that the majority disappear spontaneously.

The NHS says very small spots called milia often appear on a baby's face when they are a few days old, usually on the nose, but they can also be on other parts of the face, inside the mouth, or on the scalp or chest. Milia can also affect older babies and children, with spots on the eyelids, forehead or nappy area. They may look white or yellow depending on skin colour.

The NHS page on rashes in babies and children separates milia from other newborn rashes. As a parent, you may know if your child seems seriously unwell: the NHS says to call 999 or go to A&E if a child with a rash has a stiff neck, difficulty breathing, is confused, or has a rash that looks like small bruises and does not fade when you press a glass against it.

It says to ask for an urgent GP appointment or get help from NHS 111 if your child has a rash you are worried about, is under 3 months old with a temperature of 38C, or is 3 months or older with a temperature of 39C or higher.

The PCDS says the face is the most common site, especially the eyelids and cheeks, though any site can be affected in relation to skin damage. Lesions are monomorphous, meaning they look the same as each other.

The PCDS says they are occasionally grouped on a plaque, which may be secondary to skin damage such as a scar.

Milia on their own are not a reason for urgent care. See a GP if the diagnosis is unclear, if the bumps are red, painful, itchy or growing, if there are lots of them following a blistering rash, or if you want advice about removal.

For a baby with any rash who is unwell, drowsy, feeding poorly or has a fever, use NHS 111 or call 999 as the NHS advises.

On the NHS, milia in babies are usually identified by a midwife, health visitor or GP and need no treatment. Removal in adults is usually done privately. If you consider this, ask how infection is avoided and what aftercare to expect.