The physical and behavioral symptoms of anorexia nervosa relate to how starvation affects the brain. It may be hard to notice symptoms because what is seen as a low body weight differs for each person. Some people with anorexia may not look very thin. Also, people often hide their thinness, eating habits or physical problems.

Physical symptoms

Physical symptoms of anorexia nervosa may include irregular heart rhythms, low blood pressure and dehydration. Dehydration happens when your body doesn't have enough water and other fluids to carry out normal functions. Your fingers may look blue and you may have dry skin. You may notice a change in your skin color, such as yellowing of the skin. You may have hair that thins, breaks or falls out. You also may have soft, downy hair covering your body.

Other physical symptoms include:

• Extreme weight loss or not making expected weight gains based on age.
• Being very tired and weak.
• Dizziness or fainting.
• Having a hard time passing stool and having stomach pain.
• Not able to stand the cold, or feeling cold when others feel fine.
• Swelling of the arms or legs.
• Wearing away of the teeth and calluses on your knuckles from causing yourself to vomit.
• Stomachaches.
• Never feeling hungry or feeling hungry and getting full right away after eating a very small portion.
• Having a hard time concentrating or focusing.
• Low mood.
• Increased anxiety.
• Stress fractures or reduced bone mass.

If you're female and not taking a contraceptive, you may not have menstrual periods.

Emotional and behavioral symptoms

You may have an extreme focus on food. Sometimes this includes cooking meals for others but not eating those meals. You may skip meals or refuse to eat. You also may severely limit the amount of food you eat through dieting or fasting, not admit to being hungry, or make excuses for not eating.

When you eat, you may eat only a few certain "safe" foods — often foods low in fat and calories. You also may focus too much on eating "clean" or healthy and stop eating specific types of food in a way that has not been recommended by a healthcare professional. You may take on rigid meal or eating habits, such as spitting out food after chewing. You may not want to eat in public. You also may lie about how much food you've eaten.

You may have a type of anorexia where you binge and purge like with bulimia. Binges are when you feel like you can't control what or how much you eat. Binges can sometimes be large amounts of food. But overall, if you have the binge-purge type of anorexia, you eat much less than you need. Purges are when you make yourself vomit, or you misuse enemas, laxatives, diuretics, diet aids or herbal products to get rid of food that you ate. You lose too much weight and have very low body weight, compared with your personal weight history.

Other emotional and behavioral symptoms of anorexia may include:

• Too much exercise. This includes exercising when you're injured, instead of doing something you value or enjoy, or exercising to such a degree of intensity that it's notably different from the people around you.
• Fear of weight gain. Being scared to gain weight may include the need to weigh or measure your body over and over again.
• Focus on appearance. This includes checking in the mirror often for what you think are flaws and wearing layers of clothing to cover up.
• Concern about being overweight. This includes concerns about being fat or having parts of the body that are fat.
• Emotional changes. You may lack emotion or feel emotionally flat. You may not want to be social. You also could be angry or irritable. You may have little interest in sex.
• Trouble sleeping. This also is known as insomnia.

You also may hurt yourself. Or you may think or talk about suicide or attempt suicide.

When to see a doctor

Because of how malnutrition affects the brain, someone with anorexia may not want to be treated. A core feature of anorexia is that people with the eating disorder usually don't see how serious their symptoms are. This is because of the way anorexia affects the brain.

If someone in your life has anorexia, it's better to take action — even if you think it could be an overreaction — rather than let symptoms continue. Early treatment of eating disorders leads to the best outcomes.

If you're worried about a loved one, urge your loved one to talk to a healthcare professional. If you're a parent or caregiver who is concerned about your child's eating habits, weight or body image, share your concerns with your child's healthcare professional.

If you think you have an eating disorder, get help. If you're thinking about suicide, contact a suicide hotline. In the U.S., call or text 988 to reach the 988 Suicide & Crisis Lifeline, available 24 hours a day, seven days a week. Or use the Lifeline Chat. Services are free and confidential. The Suicide & Crisis Lifeline in the U.S. has a Spanish language phone line at 1-888-628-9454 (toll-free).

The causes of anorexia nervosa aren't known. As with many diseases, it's probably a mix of factors:

• Genetics. Although it isn't yet clear which genes are involved, genetic changes may make you more likely to develop anorexia. That involves having genetic traits that include feeling the need to be perfect or being very sensitive.
• Mental health. People with eating disorders sometimes have obsessive-compulsive personality traits that make it easier to stick to strict diets and not eat, even though they're hungry. They also may try to be perfect in everything they do.
• Environmental. Modern Western culture puts a lot of focus on being thin. Social media plays a big role. Peer pressure may cause you to want to be thin, lean or muscular. A constant push to eat a healthy diet could lead to very strict eating habits. These habits could turn into eating disorders.

Anorexia nervosa affects all gender identities, races, ages, incomes and body types.

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

Certain factors raise the risk of anorexia and other eating disorders, including:

• Family history. If you have a first-degree relative — a parent, sibling or child — who had anorexia, you have a higher risk of developing it.
• A history of weight bullying. People who have been teased or bullied about their weight are more likely to develop eating disorders. This includes people with peers, family members, coaches and others who have shamed them for their weight.
• A history of dieting. Dieting behaviors raise the risk of an eating disorder. People who are always dieting and whose weight is always going up and down as they get on and off new diets could develop an eating disorder.
• Transitions. Major changes can bring emotional stress and raise the risk of anorexia. Such changes include a new school, home or job, as well as a relationship breakup or the death or illness of a loved one.

Anorexia nervosa can have many complications. At its most severe, it can be fatal. Death may happen suddenly — even if you aren't visibly underweight. Irregular heart rhythms, also known as arrhythmias, can lead to death. Also, an imbalance of electrolytes — minerals such as sodium, potassium and calcium that maintain the balance of fluids in the body — also can lead to death.

Other complications of anorexia include:

• Anemia.
• Other heart conditions, such as mitral valve prolapse or heart failure. Mitral valve prolapse happens when the valve between the heart's upper and lower left chambers doesn't close properly.
• Bone loss, also known as osteoporosis, which can raise the risk of fractures.
• Loss of muscle.
• Stomach problems, such as constipation, bloating or nausea.
• Kidney problems.

In females, anorexia can lead to having no period. In males, it can decrease testosterone.

If you become severely malnourished, every organ system in your body can be damaged. This damage may not be fully reversible, even when the anorexia is under control.

In addition to physical complications, you also may have other mental health symptoms and conditions, including:

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

There's no guaranteed way to prevent anorexia nervosa. Primary healthcare professionals, including pediatricians, family medicine professionals and internal medicine professionals, may be in a good position to see early signs that could lead to anorexia. For instance, they can ask questions about eating habits and satisfaction with appearance during routine medical appointments. This could open a discussion about how this relates to health and where to get help if needed.

If you notice that people have dieting habits that seem too rigid, or they're unhappy with their appearance, think about talking to them about these issues. Although you may not be able to prevent an eating disorder from starting, you can talk about your concerns and offer to assist them in finding help if needed.

Examples of organizations that offer support for caregivers, friends and family members of people with eating disorders include the National Eating Disorders Association (NEDA) and Families Empowered and Supporting Treatment for Eating Disorders (F.E.A.S.T.).

If your healthcare professional thinks that you have anorexia nervosa, you may have several tests and exams to 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 exam includes measuring your height and weight and checking your vital signs. Vital signs include heart rate, blood pressure and temperature. Usually, the exam also includes checking skin and nails for problems, listening to the heart and lungs, and looking at the stomach area.
• Lab tests. These may include a complete blood count (CBC) and more-specialized blood tests to check electrolytes and protein, as well as the function of your liver, kidney and thyroid. A urine test also may be done.
• Mental health evaluation. Your healthcare professional likely will ask about your thoughts, feelings and eating habits. Your healthcare professional also may ask you to answer a series of questions about your health.
• 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. An electrocardiogram may be done to look for heart issues.

It's best to treat anorexia nervosa using a team approach. The team includes doctors, mental health professionals and other healthcare professionals — all with experience in treating eating disorders.

Here's a look at what's commonly involved in treatment.

Hospital stays and other programs

If your life is in danger now, you may need to be treated in a hospital emergency department. This may be needed for issues such as a heart rhythm problem, dehydration, electrolyte imbalances or a mental health emergency. A hospital stay may be needed to treat medical complications, severe mental health problems, severe malnutrition or continued refusal to eat.

Some clinics specialize in treating eating disorders. They may offer day treatment programs or residential treatment programs rather than a hospital stay. Specialized eating disorder programs may offer more-intensive treatment over longer periods of time. The main goal is to make eating patterns more typical and promote behaviors to support weight gain. The second goal is to help change distorted beliefs and thoughts that maintain limited eating.

Medical care

You may need to be monitored often because of all the complications anorexia causes. This includes your vital signs, hydration level and electrolytes, as well as related physical conditions. In severe cases, you may at first require feeding through a tube that's placed in your nose and goes to the stomach. This is called a nasogastric tube.

Restoring a healthy weight

The first goal of treatment is to get to a healthy weight based on your personal growth history. You can't recover from anorexia without returning to a healthy weight and good eating habits. People involved in this process may include:

• Your healthcare professional, who can provide medical care and supervise your weight gain.
• A psychologist or another mental health professional trained to treat eating disorders, who can work with you on ways to change your behavior to help you return to a healthy weight.
• A dietitian, who is specially trained in eating disorders and can guide you on how to get back to regular patterns of eating. This includes giving you meal plans that meet your calorie needs and help you reach your weight goals.
• Your family, who will likely be involved in helping you keep good eating habits. This is especially true for children and teenagers with eating disorders.

Family-based treatment for teenagers

Family-based treatment, sometimes called FBT, is the only proven outpatient treatment for teenagers with anorexia. A person with anorexia can't make good choices about eating and health due to the impact of the disorder on the brain. So this therapy helps parents help their child eat right and get to a healthy weight until the child can make good choices about health.

Medicines

Unfortunately, no medicines have been found to help treat anorexia nervosa. For people who have anorexia, being underweight may interfere with the effectiveness of medicines they take for other conditions, including depression and anxiety. For people with anorexia, food is truly the medicine.

Some people may need supplements to reverse the effects of malnutrition, but most people should get the nutrients they need through food by getting back to regular eating habits and a healthy weight. Your healthcare professional may recommend taking supplements such as vitamin D, though it's important to talk to your healthcare professional to make sure you're taking the right things in the right way.

Treatment challenges in anorexia

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

• Thinking that treatment isn't needed or that you're not sick enough to be treated.
• Fearing weight gain.
• Seeing anorexia as a lifestyle choice rather than an illness.

Recovery is possible with proven treatment that includes reaching a healthy weight. But you're at higher risk of anorexia returning during periods of high stress or triggering situations. Ongoing therapy or periodic appointments during times of stress may help you stay healthy.

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

• Stay with 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 healthcare professional about proper vitamin and mineral supplements. Many people get their vitamins and minerals from food. But if you're not eating well, your body probably isn't getting all the nutrients it needs, such as vitamin D or iron.
• 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 outside of medical appointments or check yourself in the mirror frequently. These actions may do nothing but fuel your drive to keep unhealthy habits.

If you have anorexia nervosa, you may misuse dietary supplements, herbal products designed to make you lose weight or feel less hungry, stimulants or insulin. All these products and medicines can have serious side effects and not work well with other medicines. They also are very dangerous to those who are underweight and can increase your risk of dying from complications greatly.

Methods that help lower anxiety and help with anorexia treatment may raise your sense of well-being and help you relax. Examples of these methods include massage, yoga and meditation.

You may find it hard to cope with anorexia nervosa when media and culture — and maybe your own family or friends — give you mixed messages about what you should look like. Whether you have anorexia or your loved one has anorexia, ask your healthcare professional for advice on coping strategies and emotional support around diet culture and weight stigma that are so common. Learning effective coping strategies and getting the support you need from family and friends are vital to successful treatment.

Here's some information to help you get ready for your appointment and know what to expect from your healthcare professional.

You may want to ask a family member or friend to go with you. Someone who goes with you may remember something that you missed or forgot. A family member also may be able to give your healthcare professional a fuller picture of your home life.

What you can do

Before your appointment, make a list of:

• Any symptoms you're having, including any that don't seem to be related to the reason for the appointment. Try to recall when your symptoms began.
• Key personal information, including any major stresses or recent life changes.
• All medicines, vitamins, herbal products, medicines available without a prescription and other supplements you take, and their doses.
• Questions to ask your healthcare professional so that you'll remember to cover everything you wanted to.

For children, it's very helpful to take along a copy of their growth curve history so that the healthcare professional can see the changes.

Some questions you might want to ask your healthcare professional include:

• What kinds of tests do I need? Do I need to prepare for these tests?
• Is this condition temporary or long-lasting?
• What treatments do you recommend?
• Are there any brochures or other printed material that I can have? What websites do you recommend?

Don't hesitate to ask other questions during your appointment.

What to expect from your doctor

Your healthcare professional likely will ask you several questions, including:

• How long have you been worried about your weight?
• How often do you exercise?
• What ways have you used to lose weight?
• Are you having any physical symptoms?
• Have you ever vomited because you were uncomfortably full?
• Do you think about food often?
• Do you ever eat in secret?
• Have others expressed concern that you're too thin?
• Have any of your family members ever had symptoms of an eating disorder or been diagnosed with an eating disorder?

Be ready to answer these questions to make sure there's time to go over any points you want to focus on.