What is lanugo hair

Lanugo is the first type of hair to develop in humans. Lanugo arises at about 3 months into development. Lanugo hair growth starts on the scalp (around the eyebrow, nose, and forehead area) and proceeds in a cephalocaudal direction (from head to toe). Lanugo is shed at about 33 to 36 weeks gestation, when it is subsequently incorporated into the amniotic fluid, eventually contributing to the composition of the meconium. Languo is fine, soft, unpigmented hair that is often present in fetuses, newborns, and in certain disease states, for example, anorexia ¹. While lanugo is a normal finding in fetuses, its presence becomes more indicative of pathology in an older person than in a younger person, for example, lanugo in a 20-year-old is more worrisome than lanugo in a neonate. Many different cell types and molecular mechanisms contribute to the development of lanugo.

Lanugo is ultimately replaced by villus (fine, thin hair) and terminal hair (thicker hairs found on the scalp, axilla, and genitalia). Often, lanugo is still present on the neonate (found in up to 30% of newborns). This is a normal finding.

If lanugo is present at birth, it is usually a benign physical exam finding. After the vernix is removed, small amounts of lanugo can remain on the newborn baby temporarily. Lanugo can thus be present on the newborn baby for the first few weeks of life. Its presence can, however, indicate premature birth in a minority of cases. When present in an adult, lanugo can be a sign of serious underlying disease states. These include, most notably, anorexia, bulimia, various forms of malnutrition, and the presence of a teratoma ².

Lanugo plays an important role in binding the vernix caseosa to the skin of fetuses. The vernix caseosa is (the viscous white covering on newborns that protects their skin, prevents water loss, plays an important role in thermoregulation, and contributes to innate immunity. This protects the fetus from damaging substances found in amniotic fluid, most notably urea and electrolytes. Lanugo’s interaction with the vernix is also important in controlling the tempo of the fetal developmental rate during various times in the gestation cycle.

Lanugo hair function

Lanugo plays a vital role in binding the vernix to the skin. This protects the fetus from damaging substances found in amniotic fluid, most notably urea and electrolytes. Lanugo’s interaction with the vernix also results in an increased rate of fetal growth during development (mid-gestation) and a decreased rate of fetal growth at the end of gestation.

Lanugo fulfills its role via serving as a physical anchor between the skin and vernix. Lanugo imparts an increased surface area to the fetus, allowing more interactions between itself and the vernix (and thus a stronger anchor). Without lanugo, the vernix would not stay affixed to the skin and therefore would not be able to protect the fetus from harmful substances in the environment.

Regarding regulating fetal developmental rate, oscillations of lanugo hairs surrounded by the vernix during fetal movements in amniotic fluid activate sensitive mechanoreceptors connected to unmyelinated C-afferent fibers. These afferents function to relay impulses originating from all fetal skin dermatomes via the spinal cord and activate the vagal sensory zone, hypothalamus, and insular cortex. This results in the promotion of an “anti-stress” effect through oxytocin release. This also results in the stimulation of fetal growth by the incretin effect of various gastrointestinal hormones.

Lanugo hair anorexia

In disease states, such as malnutrition and anorexia where thermoregulation becomes disrupted, lanugo grows in adults to help insulate the body (it is a natural response to an unnatural insult, in other words, lack of thermoregulation). Molecular signals from the dermal papilla are released following the detection of temperature dysregulation and cause a series of signaling events (mostly via Smo, PTCH, and other SHH components) leading to the ultimate formation of lanugo hair. Malnutrition occurs when the supply of nutrients and energy is inadequate to meet the body’s requirements. Lanugo the fine, downy, pale hair on the back, abdomen, and forearms, resolves when normal total body fat is restored.

Worldwide, the most common cause of malnutrition is inadequate food supply. Gastrointestinal infections, particularly parasitic infections, exacerbate this problem. Preschool-aged children in developing countries are most at risk because of their increased protein and energy requirements, greater susceptibility to infection, and exposure to unhygienic conditions. Marasmus and kwashiorkor are two related disorders of severe protein-energy malnutrition that occur mainly in young children from developing countries at the time of weaning.

In developed countries, other causes of malnutrition are more prominent:

• Reduced absorption or abnormal metabolism of nutrients and energy due to illnesses such as inflammatory bowel disease (e.g. Crohn disease), gastrointestinal infections, cystic fibrosis, extensive thermal burns, or cancer.
• Insufficient food intake e.g. anorexia nervosa.
• Complex social and medical problems – for example elderly people can become malnourished due to a combination of reduced appetite, impaired mental functioning, medications, coexisting illnesses, psychosocial isolation, heavy alcohol intake, and/or depression.
• Inadequate food supply can also be a problem in low-income areas of developed countries.

Anorexia nervosa is an eating disorder defined by restriction of energy intake relative to requirements, leading to a significantly low body weight ³. Patients with anorexia nervosa have an intense fear of gaining weight and distorted body image with the inability to recognize the seriousness of their significantly low body weight ⁴.

Anorexia nervosa is more common in females than males. Onset is late adolescence and early adulthood. Lifetime prevalence is 0.3% to 1% (European studies have demonstrated the prevalence of 2% to 4%), irrespective of culture, ethnicity, and race. Risk factors for eating disorders include childhood obesity, female sex, mood disorders, personality traits (impulsivity and perfectionism), sexual abuse, or weight-related concerns from family or peer environments ⁵.

Studies demonstrate biologic factors play a role in the development of anorexia nervosa in addition to environmental factors. Genetic correlations exist between educational attainment, neuroticism, and schizophrenia. Patients with anorexia nervosa have altered brain function and structure there are deficits in neurotransmitters dopamine (eating behavior and reward) and serotonin (impulse control and neuroticism), differential activation of the corticolimbic system (appetite and fear), and diminished activity among the frontostriatal circuits (habitual behaviors). Patients have co-morbid psychiatric disorders such as major depressive disorder and generalized anxiety disorder.

Anorexia causes

The exact cause of anorexia is unknown. As with many diseases, it’s probably a combination of biological, psychological and environmental factors.

• Biological. Although it’s not yet clear which genes are involved, there may be genetic changes that make some people at higher risk of developing anorexia. Some people may have a genetic tendency toward perfectionism, sensitivity and perseverance — all traits associated with anorexia.
• Psychological. Some people with anorexia may have obsessive-compulsive personality traits that make it easier to stick to strict diets and forgo food despite being hungry. They may have an extreme drive for perfectionism, which causes them to think they’re never thin enough. And they may have high levels of anxiety and engage in restrictive eating to reduce it.
• Environmental. Modern Western culture emphasizes thinness. Success and worth are often equated with being thin. Peer pressure may help fuel the desire to be thin, particularly among young girls.

Risk factors for anorexia

Anorexia is more common in girls and women. However, boys and men have increasingly developed eating disorders, possibly related to growing social pressures.

Anorexia is also more common among teenagers. Still, people of any age can develop this eating disorder, though it’s rare in those over 40. Teens may be more at risk because of all the changes their bodies go through during puberty. They may also face increased peer pressure and be more sensitive to criticism or even casual comments about weight or body shape.

Certain factors increase the risk of anorexia, including:

• Genetics. Changes in specific genes may put certain people at higher risk of anorexia. Those with a first-degree relative — a parent, sibling or child — who had the disorder have a much higher risk of anorexia.
• Dieting and starvation. Dieting is a risk factor for developing an eating disorder. There is strong evidence that many of the symptoms of anorexia are actually symptoms of starvation. Starvation affects the brain and influences mood changes, rigidity in thinking, anxiety and reduction in appetite. Starvation and weight loss may change the way the brain works in vulnerable individuals, which may perpetuate restrictive eating behaviors and make it difficult to return to normal eating habits.
• Transitions. Whether it’s a new school, home or job; a relationship breakup; or the death or illness of a loved one, change can bring emotional stress and increase the risk of anorexia.

Anorexia prevention

There’s no guaranteed way to prevent anorexia nervosa. Primary care physicians (pediatricians, family physicians and internists) may be in a good position to identify early indicators of anorexia and prevent the development of full-blown illness. For instance, they can ask questions about eating habits and satisfaction with appearance during routine medical appointments.

If you notice that a family member or friend has low self-esteem, severe dieting habits and dissatisfaction with appearance, consider talking to him or her about these issues. Although you may not be able to prevent an eating disorder from developing, you can talk about healthier behavior or treatment options.

Anorexia symptoms

The physical signs and symptoms of anorexia nervosa are related to starvation. Anorexia also includes emotional and behavioral issues involving an unrealistic perception of body weight and an extremely strong fear of gaining weight or becoming fat.

It may be difficult to notice signs and symptoms because what is considered a low body weight is different for each person, and some individuals may not appear extremely thin. Also, people with anorexia often disguise their thinness, eating habits or physical problems.

Physical symptoms

Physical signs and symptoms of anorexia may include:

• Extreme weight loss or not making expected developmental weight gains
• Thin appearance
• Abnormal blood counts
• Fatigue
• Insomnia
• Dizziness or fainting
• Bluish discoloration of the fingers
• Hair that thins, breaks or falls out
• Soft, downy hair covering the body
• Absence of menstruation
• Constipation and abdominal pain
• Dry or yellowish skin
• Intolerance of cold
• Irregular heart rhythms
• Low blood pressure
• Dehydration
• Swelling of arms or legs
• Eroded teeth and calluses on the knuckles from induced vomiting

Some people who have anorexia binge and purge, similar to individuals who have bulimia. But people with anorexia generally struggle with an abnormally low body weight, while individuals with bulimia typically are normal to above normal weight.

Emotional and behavioral symptoms

Behavioral symptoms of anorexia may include attempts to lose weight by:

• Severely restricting food intake through dieting or fasting
• Exercising excessively
• Bingeing and self-induced vomiting to get rid of food, which may include the use of laxatives, enemas, diet aids or herbal products

Emotional and behavioral signs and symptoms may include:

• Preoccupation with food, which sometimes includes cooking elaborate meals for others but not eating them
• Frequently skipping meals or refusing to eat
• Denial of hunger or making excuses for not eating
• Eating only a few certain “safe” foods, usually those low in fat and calories
• Adopting rigid meal or eating rituals, such as spitting food out after chewing
• Not wanting to eat in public
• Lying about how much food has been eaten
• Fear of gaining weight that may include repeated weighing or measuring the body
• Frequent checking in the mirror for perceived flaws
• Complaining about being fat or having parts of the body that are fat
• Covering up in layers of clothing
• Flat mood (lack of emotion)
• Social withdrawal
• Irritability
• Insomnia
• Reduced interest in sex

Anorexia complications

Anorexia can have numerous complications. At its most severe, it can be fatal. Death may occur suddenly — even when someone is not severely underweight. This may result from abnormal heart rhythms (arrhythmias) or an imbalance of electrolytes — minerals such as sodium, potassium and calcium that maintain the balance of fluids in your body.

Other complications of anorexia include:

• Anemia
• Heart problems, such as mitral valve prolapse, abnormal heart rhythms or heart failure
• Bone loss (osteoporosis), increasing the risk of fractures
• Loss of muscle
• In females, absence of a period
• In males, decreased testosterone
• Gastrointestinal problems, such as constipation, bloating or nausea
• Electrolyte abnormalities, such as low blood potassium, sodium and chloride
• Kidney problems

If a person with anorexia becomes severely malnourished, every organ in the body can be damaged, including the brain, heart and kidneys. This damage may not be fully reversible, even when the anorexia is under control.

In addition to the host of physical complications, people with anorexia also commonly have other mental health disorders as well. They may include:

• Depression, anxiety and other mood disorders
• Personality disorders
• Obsessive-compulsive disorders
• Alcohol and substance misuse
• Self-injury, suicidal thoughts or suicide attempts

Anorexia diagnosis

If your doctor suspects that you have anorexia nervosa, he or she will typically do several tests and exams to help pinpoint a diagnosis, rule out medical causes for the weight loss, and check for any related complications.

These exams and tests generally include:

• Physical exam. This may include measuring your height and weight; checking your vital signs, such as heart rate, blood pressure and temperature; checking your skin and nails for problems; listening to your heart and lungs; and examining your abdomen.
• Lab tests. These may include a complete blood count (CBC) and more-specialized blood tests to check electrolytes and protein as well as functioning of your liver, kidney and thyroid. A urinalysis also may be done.
• Psychological evaluation. A doctor or mental health professional will likely ask about your thoughts, feelings and eating habits. You may also be asked to complete psychological self-assessment questionnaires.
• Other studies. X-rays may be taken to check your bone density, check for stress fractures or broken bones, or check for pneumonia or heart problems. Electrocardiograms may be done to look for heart irregularities.

Your mental health professional also may use the diagnostic criteria for anorexia in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), published by the American Psychiatric Association.

Anorexia treatment

Treatment for anorexia is generally done using a team approach, which includes doctors, mental health professionals and dietitians, all with experience in eating disorders. Ongoing therapy and nutrition education are highly important to continued recovery.

Here’s a look at what’s commonly involved in treating people with anorexia.

Hospitalization and other programs

If your life is in immediate danger, you may need treatment in a hospital emergency room for such issues as a heart rhythm disturbance, dehydration, electrolyte imbalances or a psychiatric emergency. Hospitalization may be required for medical complications, severe psychiatric problems, severe malnutrition or continued refusal to eat.

Some clinics specialize in treating people with eating disorders. They may offer day programs or residential programs rather than full hospitalization. Specialized eating disorder programs may offer more-intensive treatment over longer periods of time.

Medical care

Because of the host of complications anorexia causes, you may need frequent monitoring of vital signs, hydration level and electrolytes, as well as related physical conditions. In severe cases, people with anorexia may initially require feeding through a tube that’s placed in their nose and goes to the stomach (nasogastric tube).

Care is usually coordinated by a primary care doctor or a mental health professional, with other professionals involved.

Restoring a healthy weight

The first goal of treatment is getting back to a healthy weight. You can’t recover from anorexia without returning to a healthy weight and learning proper nutrition. Those involved in this process may include:

• Your primary care doctor, who can provide medical care and supervise your calorie needs and weight gain
• A psychologist or other mental health professional, who can work with you to develop behavioral strategies to help you return to a healthy weight
• A dietitian, who can offer guidance getting back to regular patterns of eating, including providing specific meal plans and calorie requirements that help you meet your weight goals
• Your family, who will likely be involved in helping you maintain normal eating habits

Psychotherapy

These types of therapy may be beneficial for anorexia:

• Family-based therapy. This is the only evidence-based treatment for teenagers with anorexia. Because the teenager with anorexia is unable to make good choices about eating and health while in the grips of this serious condition, this therapy mobilizes parents to help their child with re-feeding and weight restoration until the child can make good choices about health.
• Individual therapy. For adults, cognitive behavioral therapy — specifically enhanced cognitive behavioral therapy — has been shown to help. The main goal is to normalize eating patterns and behaviors to support weight gain. The second goal is to help change distorted beliefs and thoughts that maintain restrictive eating.

Medications

No medications are approved to treat anorexia because none has been found to work very well. However, antidepressants or other psychiatric medications can help treat other mental health disorders you may also have, such as depression or anxiety.

Home remedies

When you have anorexia, it can be difficult to take care of yourself properly. In addition to professional treatment, follow these steps:

• Stick to your treatment plan. Don’t skip therapy sessions and try not to stray from meal plans, even if they make you uncomfortable.
• Talk to your doctor about appropriate vitamin and mineral supplements. If you’re not eating well, chances are your body isn’t getting all of the nutrients it needs, such as Vitamin D or iron. However, getting most of your vitamins and minerals from food is typically recommended.
• Don’t isolate yourself from caring family members and friends who want to see you get healthy. Understand that they have your best interests at heart.
• Resist urges to weigh yourself or check yourself in the mirror frequently. These may do nothing but fuel your drive to maintain unhealthy habits.

Treatment challenges in anorexia

One of the biggest challenges in treating anorexia is that people may not want treatment. Barriers to treatment may include:

• Thinking you don’t need treatment
• Fearing weight gain
• Not seeing anorexia as an illness but rather a lifestyle choice

People with anorexia can recover. However, they’re at increased risk of relapse during periods of high stress or during triggering situations. Ongoing therapy or periodic appointments during times of stress may help you stay healthy.

1. Verhave BL, Lappin SL. Embryology, Lanugo. [Updated 2018 Oct 27]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2019 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK526092[↩]
2. Ahmed YA, Ali S, Ghallab A. Hair histology as a tool for forensic identification of some domestic animal species. EXCLI J. 2018;17:663-670[↩]
3. Moore CA, Bokor BR. Anorexia Nervosa. [Updated 2019 Jan 1]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2019 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK459148[↩]
4. Strand M, von Hausswolff-Juhlin Y, Welch E. [ARFID: food restriction without fear of weight gain]. Lakartidningen. 2018 Sep 11;115[↩]
5. Levinson CA, Zerwas SC, Brosof LC, Thornton LM, Strober M, Pivarunas B, Crowley JJ, Yilmaz Z, Berrettini WH, Brandt H, Crawford S, Fichter MM, Halmi KA, Johnson C, Kaplan AS, La Via M, Mitchell J, Rotondo A, Woodside DB, Kaye WH, Bulik CM. Associations between dimensions of anorexia nervosa and obsessive-compulsive disorder: An examination of personality and psychological factors in patients with anorexia nervosa. Eur Eat Disord Rev. 2019 Mar;27(2):161-172[↩]