Milia (singular, milium) are minute epidermoid cysts that present as small white or yellow papules, usually on the face and, particularly, around the eyes in adults. They may be derived from the pilosebaceous follicle. Primary milia affect 40%–50% of newborns but may be found in patients of all ages. Secondary milia often occur after dermabrasion or trauma or in conjunction with blistering disorders, and they are due to damage to the pilosebaceous unit. Milia may occur in tattoos.

Milia have also been known to occur in areas of steroid-induced atrophy. Persistent or widespread milia are associated with many syndromes. There is no race / ethnicity or sex predilection.