What are milia?
A milium is a small cyst containing keratin (skin protein); they are usually multiple and are then known as milia. These harmless cysts present as tiny pearly-white bumps just under the surface of the skin.
Clinical features of milia
Milia are common in all ages and both sexes. They most often arise on the face, and are particularly prominent on the eyelids and cheeks, but they may occur elsewhere.
How is the diagnosis made?
Milia have a characteristic appearance. However, on occasion, a skin biopsy may be performed. This shows a small epidermoid cyst coming from a vellus hair follicle.
Milia should be distinguished from other types of cyst, comedones, xanthelasma and syringomas. Colloid milia are golden coloured bumps on cheeks and temples associated with excessive exposure to sunlight.
They should also be distinguished from milia-like cysts noted on dermoscopy in seborrhoeic keratoses, papillomatous moles and some basal cell carcinomas.
Treatment
Milia do not need to be treated unless they are a cause for concern for the patient. They often clear up by themselves within a few months. Where possible, further trauma should be minimised to reduce development of new lesions.
- The lesion may be de-roofed using a sterile needle or blade and the contents squeezed or pricked out.
- They may be destroyed using diathermy and curettage, or cryotherapy.
- For widespread lesions topical retinoidsmay be helpful.
- Chemical peels, dermabrasionand laser ablation have been reported to be effective when used for very extensive milia.
- Milia en plaque may improve with minocycline (a tetracyclineantibiotic).