Milia are benign, small, hard, white cysts filled with keratin located just beneath the surface of the skin. Primary milia are very common in infants and require no treatment as the cysts disappear in a few weeks. Primary milia typically form on the face, usually around the eyes and nose, and can also appear on adults. There is no known cause for primary milia.

Secondary milia are usually the result of damaged skin and thus can be caused by sun exposure, overuse of topical steroids, trauma, burns, and contact with any substance that irritates the skin. Secondary milia will resolve without treatment – usually in a few weeks but can persist for months. There are rare genetic and autoimmune disorders that result in the formation of a large number of milia, known as milia en plaque.

No matter what the cause milia are completely benign and require no treatment. However, if treatment is desired they can easily be removed by a dermatologist or esthetician. There are many methods that can be used to remove these cysts, including deroofing (using a fine blade to remove the top of the cyst, allowing the keratin to be removed), cryotherapy (freezing the lesion), and electrodessication (using heat to destroy the lesion). Milia en plaque has successfully been treated with topical tretinoin (retin-a), etretinate, and minocycline. It is important to note that milia are not acne and will not respond to typical remedies for acne. In fact, using acne treatments for milia can result in skin damage and should be avoided.