What are milia and what do they look like?
A milium is a small, raised bump on the skin. It is a type of tiny skin cyst filled with a protein called keratin.
Many are usually found together and so they are called milia (the plural of milium).
As can be seen in the picture, milia are usually each about 1 or 2 millimetres across and are pearly-white or yellowish.
They are most often seen on the skin around the cheeks, nose, eyes and eyelids, forehead and chest but they can occur anywhere on the body.
What are the types of milia and what causes them?
There are different types of milia. We do not fully understand what causes all of the different types.
- Neonatal milia. These are milia that are seen in young babies soon after they are born. They are very common and are usually found around the nose area but may also occur on the scalp, cheeks, upper body and inside the mouth. They are thought to arise from sebaceous (sweat) glands that aren’t fully developed or mature. Around half of all babies develop neonatal milia. In fact, because they are so common, they are actually considered as normal in newborn babies.
- Primary milia. These are milia that can occur in both children and adults.
- Secondary milia. These are milia that develop in an area of skin, anywhere on the body, that has previously been damaged or injured – for example, after a burn or a blistering rash. The milia develop as the skin heals and it is thought that damage to the sweat glands may be an underlying cause. Secondary milia also sometimes develop after certain skin creams have been used – for example, corticosteroid skin creams.
- Milia en plaque. Milia of this type are rare. The milia develop on an inflamed, raised patch of skin known as a plaque which may be several centimetres across. The cause for milia en plaque is not fully understood. It usually occurs behind the ears, on an eyelid, or on the cheeks or jaw area. This type of milia tends to particularly affect middle-aged women.
- Multiple eruptive milia. These are crops, or patches of milia that develop over a period of weeks or months. The crops usually appear on the face, the upper arms and the upper trunk. Milia of this type are also rare.
Do milia cause any symptoms?
Milia do not usually cause any symptoms but, in some people, they can become itchy.
How are milia diagnosed?
Milia are usually diagnosed by their typical appearance and generally no investigations are needed. However, in a few cases, if the diagnosis is uncertain or if milia en plaque are suspected, your doctor may suggest a skin biopsy. During a skin biopsy, a small piece of skin is removed so that it can be examined under a microscope. There are different ways that a skin biopsy can be carried out. For example, by shaving away a small piece of skin or by using a special instrument to punch a tiny hole in the skin.
Is any treatment needed?
Milia are harmless and, in most cases, they will eventually clear by themselves. In babies, they clear after a few weeks but, in some people, milia can persist for months or sometimes longer. Secondary milia are sometimes permanent.
Because they normally clear by themselves, milia do not usually need any treatment. However, some people find milia unsightly and so opt for treatment. Milia may be removed using a fine needle and then squeezing, or pricking, out the contents. No anaesthetic is needed. However, it is not recommended to squeeze or try to treat milia yourself. This can lead to skin damage and scarring or infection.
If milia become very widespread and persistent, various other treatments may be suggested, usually by a skin specialist (a dermatologist). They include:
- Cryotherapy (a type of treatment that freezes skin lesions – a skin lesion is where a patch of skin has changed in appearance).
- Laser treatment.
- Dermabrasion (a procedure that removes the topmost layers of the affected skin).
- Chemical peeling (a treatment where a chemical is applied to the face to burn off skin lesions).
In the rare type of milia called milia en plaque, certain creams such as isotretinoin or tretinoin are sometimes suggested as treatment, or the antibiotic tablet, minocycline.