Lanugo hair will invariably be shed by three to four months after birth.

As the person ages, the lanugo hair may thin, leaving only limited areas of hypertrichosis.

Lanugo hair on the body sometimes turns darker.

Lanugo hair is a much thicker type of hair that, in human forms, normally grows only on fetuses.

Vellus hair replaces lanugo hair on a human fetus at 36 to 40 weeks of gestation.

Vellus hair is not lanugo hair.

Hypertrichosis lanuginosa Acquired hypertrichosis lanuginosa is characterized by rapid growth of lanugo hair, particularly on the face.

Vernix has a highly variable makeup but is primarily composed of sebum, cells that have sloughed off the fetus's skin and shed lanugo hair.

Hypertrichosis lanuginosa Congenital hypertrichosis lanuginosa is noticeable at birth, with the infant completely covered in thin lanugo hair.

This view is currently controversial and a histological study reported that the mucosal surface of the prepuce is completely free of lanugo hair follicles, apocrine (sweat) and sebaceous glands.

In normal circumstances, lanugo hair is shed before birth and replaced by vellus hair; however, in a person with congenital hypertrichosis lanuginosa, the lanugo hair remains after birth.