Anorexia nervosa may result in the development of what unusual body hair condition?

In individuals with anorexia nervosa, one significant physiological response to severe malnutrition and weight loss is the development of lanugo. Lanugo is a fine, soft hair that typically appears on the body in areas where there is a lack of body fat and is a mechanism the body employs to help maintain warmth and insulation when subcutaneous fat is insufficient. This type of hair is often seen in infants but can also occur in adults facing extreme weight loss and malnutrition, as seen in anorexia nervosa.

The presence of lanugo is the body's way of trying to cope with significant loss of body fat and temperature regulation issues. It is not a typical occurrence in healthy individuals and specifically indicates a severe energy deficit and disruption in hormonal balance due to the lack of adequate nutrition. This makes lanugo a unique condition associated specifically with anorexia nervosa, distinguishing it from other types of hair growth disorders that are not linked to malnutrition.