Milium is a tiny asymptomatic keratinous cyst, the cause of which is unknown. Its clinical appearance is a round or oval, white or yellowish body directly beneath the surface of the skin. Milia are common. They occur singly or in groups and measure only 1 to 2 mm in diameter (Fig. 49-1). The cheeks, eyelids, forehead, temples, penis, scrotum, and the internal aspect of the labia minora are the favored sites. All age-groups are affected. Facial milia can be found in 50% of newborn infants; these lesions disappear spontaneously in a few weeks. Similar lesions in older children and adults sometimes disappear without treatment but usually persist indefinitely.