lanugo

Human hair
By area Androgenic hair Facial hair Chest hair Underarm hair Abdominal hair Arm hair Leg hair Pubic hair
By type Vellus hair Terminal hair Lanugo
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Related topics Human hair color Hairstyle Hypertrichosis Stubble Trichophilia
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Lanugo is fine, downy hair; it is a type of pelage.

In humans

Fetal development

Lanugo grows on fetuses as a normal part of gestation, but is usually shed and replaced by vellus hair at about 33 to 36 weeks of gestational age. As the lanugo is shed from the skin, it is normal for the developing fetus to consume the hair with the fluid, since it drinks from the amniotic fluid and urinates it back into its environment. Subsequently, the lanugo contributes to the newborn baby's meconium. The presence of lanugo in newborns is a sign of premature birth.

Malnutrition

Lanugo in grown humans is also a possible sign of starvation, as the body attempts to insulate itself when body fat is lost. This is why the presence of lanugo is one of the more visible signs of severe and prolonged anorexia.^[1]

In non-human animals

Lanugo is also common on other animals. For example, seals^[2] and elephants^[3][4][5] are often born with a covering of lanugo.

References

External links

• Photo of lanugo in a human infant, The Royal Infirmary of Edinburgh