Lanugo

Lanugo

Lanugo is a fine, soft, and usually unpigmented hair that covers the body of a fetus. It is a normal part of fetal development and plays a crucial role in protecting the delicate skin of the fetus. This article will explore the characteristics, development, and significance of lanugo, as well as its clinical implications.

Characteristics

Lanugo is characterized by its fine texture and lack of pigmentation. It is often described as downy or woolly in appearance. Unlike terminal hair, which is thicker and pigmented, lanugo is much finer and lighter. It covers most of the fetal body, including areas that are not typically hairy in adults, such as the face and back.

Development

Lanugo begins to develop around the 16th week of gestation and is most prominent by the 20th week. It is thought to help anchor the vernix caseosa, a waxy substance that protects the fetal skin from amniotic fluid. Lanugo is usually shed before birth, typically around the 7th or 8th month of gestation, but it can persist in some newborns, especially those born prematurely.

Function

The primary function of lanugo is to protect the fetus's skin. By holding the vernix caseosa in place, lanugo helps to prevent the skin from becoming waterlogged and damaged by the amniotic fluid. Additionally, lanugo may play a role in regulating the fetus's body temperature by providing a layer of insulation.

Clinical Significance

While lanugo is a normal part of fetal development, its presence in older children or adults can be a sign of certain medical conditions. For example, lanugo is often seen in individuals with anorexia nervosa, as the body attempts to insulate itself due to a lack of body fat. It can also be present in other conditions that involve malnutrition or hormonal imbalances.

Also see

• Vernix caseosa
• Fetal development
• Anorexia nervosa
• Hair follicle