Milia

Milia (milium - singular) are small, sub-epidermal keratin containing cysts. They mainly arise from undeveloped sebaceous glands, and sometimes from sweat glands. Milia are very common and present as small pearly-white bumps just under the skin surface and most commonly around the eyes.

This chapter is set out as follows:

Primary milia

• Are common in the newborn affecting approximately 50% of babies. They resolve over a short period of time
• Can also arise in children and young adults

Eruptive milia

• Most commonly seen in young women, perhaps as a sequel to sunbathing

Skin damage

• Milia can arise as a result of skin damage
• This can be mechanical (eg a burn, dermabrasion), part of a dermatological condition (eg porphyria cutanea tarda and other bullous conditions) or iatrogenic (eg chronic steroid-induced atrophy or post radiotherapy)

Distribution

• The face is the most common site, especially the eyelids and cheeks
• Any site can be affected in relationship to skin damage

Morphology

• Usually situated on normal surrounding skin
• Occasionally grouped on a plaque when may be secondary to skin damage
• Monomorphous (ie lesions have the same appearance)
• 1-2 mm diameter, uniform and spherical lesions protruding from just under the skin surface 
• White > yellow

• Treatment is not necessary and spontaneous disappearance occurs in the majority

• In adults the surface of the milia can be broken (eg with a sterile needle or the point of a blade), and the contents squeezed out. The careful use of cryotherapy or diathermy can also be effective