In these days of struggles over obesity, it may be hard to remember that being too thin may be a bigger health threat than being too fat. Anorexia nervosa is a very serious but hidden disorder in which the person has a relentless pursuit of thinness, is unwilling to maintain a healthy weight, has distorted body image and intense fear of gaining weight, disturbed eating behavior, and, in girls, amenorrhea.

Anorexia nervosa is actually the third-leading chronic illness in adolescent females and has a mortality rate as high as 20% – one-third by suicide. Boys are not only not immune, but also are even more difficult to suspect and detect. While most affected children improve with behavioral treatment, anorexia nervosa severe enough to warrant hospitalization can result in permanent damage to bones, heart, and brain.

I refer to these patients as “children” here, but you may rightly associate anorexia with adolescents: 43% of those affected had onset at 16-20 years and 86% by 20 years. But listen to this disturbing statistic: 42% of 1st-3rd grade girls report that they want to be thinner and 81% of 10-year-olds are “afraid” of being fat. Over half of teen girls and one-third of boys skip meals, fast, smoke cigarettes, vomit, or take laxatives to control weight – ineffective practices that can lead to eating disorders. Healthy foods and exercise may seem too slow or difficult ways to control weight.

Even with a prevalence of 0.5% you may be wondering, “Gee, I haven’t seen anyone with that for years!” But you probably have been seeing children with the most common presentations of anorexia, which are concerns over complications rather than a request for help with excess weight loss. These are usually complaints about abdominal pain, bloating, or constipation, but may be about headaches, amenorrhea, or feeling faint. You may see them for the first time after an intercurrent illness such as viral gastroenteritis or mononucleosis that sends their emaciated bodies over the edge. Do those patients sound more familiar?

Anorexia nervosa works its damage from starvation and purging behaviors. Any system of the body can be affected from starvation, ranging from suppression of bone marrow with anemia, low white count, and low platelets; endocrine suppression with low TSH and T4 and amenorrhea; cardiomyopathy with resulting mitral valve prolapse, arrhythmias, and syncope; or even seizures and brain atrophy. Depression and anxiety are pretty inevitable when one is starving but, while comorbid, their primacy or severity really can’t be assessed until the starvation state is resolved.

Why aren’t the affected children worried about these serious complications? Actually, they may be worried when they find out about them, but their first fear is about getting fat. Characteristic of anorexia is a distorted body image that nags at them incessantly to lose weight. In U.S. culture, weight loss and fitness ads are all around us, making this concern seem quite normal or even more urgent. They may even panic and get angry if their excessive exercise routine is interrupted. The missing link is that they can’t see that they are not overweight, instead fearing being fat.

Many children with anorexia have tried to stop their dieting but failed. They may be ashamed, embarrassed, or worried about being stigmatized if they are found out. But they often feel that they are on the right path for themselves. At best they are ambivalent about being detected and pushed into treatment. So they get really good at hiding their condition, sometimes getting new ideas online. Common strategies to evade detection include eating apart from the family, saying they are “not hungry now” or even cooking for others but not eating themselves. They wear baggy clothes to hide their emaciation. They often exercise to an extreme, in any weather, whether sick or well. When it is time to be weighed they may drink quarts of water and fill pockets with stones so their true weight loss is not evident.

Actions children take for weight control or loss create much of the morbidity. Most common are use of laxatives and diuretics that can result in fatal electrolyte imbalances and arrhythmias. Purging in anorexia and also in bulimia nervosa can result in gastroesophageal reflux disease, esophageal tears, and bleeding. Self-induced vomiting also destroys tooth enamel, fosters cavities, and can cause scars of palate or knuckles from forcing their hand down their throat. Hypoglycemia from severe restriction can even result in seizures.

When your patients have those metabolic and physical signs, you are not likely to be tricked into thinking all is well. But those athletes in your practice, of whom you and the parents are so proud, can sneak up on you. Those participating in individual “aesthetic” sports such as dance, figure skating, and gymnastics are especially vulnerable to (and rewarded by) extreme thinness. They have been coached to be slim. But to make it worse, the most elite athletes also often have personalities that make extreme weight control possible including perfectionism, competitiveness, compulsiveness, drive, and high activity level.

Parents of children with anorexia may be ambivalent, also, as they see their child eating healthy foods and exercising as they have encouraged them to do. It is not so clear when they have gone too far. But 35% of “normal dieters” go on to pathological dieting and, of those, 20%-25% develop eating disorders of varying degree.

As with most disorders, earlier detection of anorexia symptoms can allow for an easier treatment course and fewer long-term complications. So, when should you be thinking and asking about abnormal eating? Certainly, it is time to ask questions when a child is not gaining weight appropriately, is losing weight to below 15% of appropriate weight for height, or has 3 or more months of amenorrhea. But also consider it when you hear complaints of abdominal pain, headache, or feeling faint that you can’t explain. Ask directly “What would you like to weigh?” A desired weight that would give a body mass index (BMI) of <19 kg/m2 is nearly diagnostic. Also ask them to, “Tell me what you eat at each meal on a typical day,” looking for extremely low-calorie bizarre choices such as all lettuce, and “How much exercise do you do daily?” Be specific in collecting information about dieting, binging, self-induced vomiting, and use of laxatives, diuretics, or diet pills for weight control. Asking family members what they have observed about the child’s exercise, dieting, and statements about body image gives even more objective information that the child may try to obscure.

Specific screening self report tools such as the SCOFF questionnaire and Patient Health Questionnaire – Adolescents ( PHQ-A ) used for all teens or those with signs of weight loss are both a way to get more accurate information and a valuable point of conversation.

When you detect signs and symptoms, the initial work up should include complete blood count, electrolytes, liver function, thyroid-stimulating hormone, and urinalysis, but most importantly an accurate height, weight, and BMI measured in underwear in a gown. Amenorrhea may require endocrine tests as well. While malignancy, endocrine and gastrointestinal disorders are in the differential, characteristic history, physical exam, and lab results will point to the diagnosis. If there is bradycardia or low potassium, chloride, or sodium, an electrocardiogram and hospitalization are urgent as these are the harbingers of life-threatening arrhythmias that are the most common cause of death.

So when you suspect anorexia, you may be facing a difficult-to-detect, life-threatening condition with resistant patients and even reluctant parents. While you may be able to make a contract for biweekly weigh-ins and coaching for subclinical anorexia not otherwise specified, a team will be needed in most full-blown cases. Eating disorder programs are often part of departments of psychiatry, but adolescent specialists also may have assembled needed teams.

Dr. Howard is assistant professor of pediatrics at the Johns Hopkins University School of Medicine, Baltimore, and creator of CHADIS. She has no other relevant disclosures. Dr. Howard’s contribution to this publication was as a paid expert to Frontline. E-mail her at