What to Know About Lanugo and Anorexia

Medically Reviewed by Dan Brennan, MD on October 25, 2021
3 min read

If you’ve ever held a newborn baby, you may have noticed a layer of soft, downy hair over their body. This hair, known as lanugo, usually goes away within a couple of weeks. But lanugo can also show up in adults, especially those with eating disorders.

Lanugo is soft, feathery hair that can grow all over the body, most often on the back and shoulders. Fetuses grow lanugo during the end of pregnancy, and newborns usually lose their lanugo within a week or two of being born.

Experts don’t really know what causes lanugo. The most common theory is that it helps insulate a body that might otherwise have a hard time staying warm.

Lanugo is common among infants but not with older children or adults.

There are a couple of conditions that can cause lanugo in adults or teens.

Most of these conditions would cause a person to have a hard time regulating their body heat. This may support the theory that lanugo grows to help insulate the body.

For example, one study looked at lanugo in people with certain types of cancer. Other research found a link between lanugo and celiac disease.

Eating disorders like anorexia nervosa are the most common reason why an adult or teenager would have lanugo.

Anorexia nervosa is an eating disorder that affects about 0.6% of adults. Like most eating disorders, it affects more females than males.

Anorexia is diagnosed in people who starve themselves as a way to lose weight. This can include limiting how often they eat, limiting how much they eat at one sitting, exercising a lot to offset what they eat, and making themselves throw up after they eat.

Doctors aren’t exactly sure what causes anorexia.

Because it happens most often in teenagers and young adults, some experts believe that rapid growth and hormonal changes can cause young people to become focused on the way they look.

People may also have anorexia because of stress, low self-esteem, anxiety, loneliness, their personal relationship with food, and their environment. Anorexia is probably caused by a combination of these things rather than by any one factor.

Anorexia can be deadly. Your body needs food to survive. It takes essential nutrients from your food and uses them to fuel everything from your organs to your skin and hair.

When your body doesn’t get the nutrients it needs, it starts to shut down. This is when dieting becomes anorexia.

Physical symptoms of anorexia include:

  • Exhaustion
  • Dizziness
  • Lack of periods (in females)
  • Constipation
  • Low blood pressure
  • Dehydration
  • Brittle hair
  • Discolored skin

Over time, anorexia can cause many medical complications including:

Lanugo is one of the symptoms of anorexia.

Unlike other symptoms, it’s almost always present in cases of severe anorexia. It’s also a unique symptom, rarely found with other medical conditions.

All of these things make the presence of lanugo useful for doctors trying to diagnose anorexia nervosa. If they notice lanugo, doctors may be able to spot and diagnose anorexia in people reluctant to seek help.

Many people with eating disorders don’t want help. They may be in denial about how bad their eating disorder has gotten, or they may want to be thin more than they want to be healthy.

Lanugo is usually a sign that anorexia has progressed to a dangerous level. And if it’s not an eating disorder, lanugo may be a sign of another underlying medical condition. 

This is why, if you or a loved one has lanugo, it’s important to talk to a doctor as soon as possible.