Children's Health: The Complete Guide

Key numbers at a glance

What keeps children healthy

Children are not small adults. Their bodies and brains are growing fast, their immune systems are meeting most germs for the first time, and they depend on the adults around them for food, sleep, safety and care. That is why so much of children's health comes down to everyday routines rather than dramatic medical decisions. A child who sleeps enough, eats a reasonable mix of foods, moves every day, is fully vaccinated and lives in a home where common hazards are dealt with starts from a strong position.

The other big idea is that change over time matters more than any single moment. A child who is a little short or light for their age but growing steadily along their own curve is usually fine. A child who is slipping away from their curve, losing skills they once had, or changing in mood and behavior over weeks deserves a closer look. Your child's doctor sees a snapshot at each visit; you see the whole film. Your observations are real medical information.

This guide walks through the main areas in roughly the order families meet them, from the routine checkups of infancy to the mental health and independence of the teen years. It focuses on what US guidelines recommend and why, so you can make choices with confidence and know which signs mean you should act quickly. It does not replace the advice of the doctor who knows your child, but it should help you ask sharper questions.

Well-child visits and screening

Well-child visits are scheduled checkups that happen whether or not your child is sick. They are packed most closely together in the first two years, when growth and development move fastest, and then become yearly through childhood and the teen years. At each visit the doctor or nurse practitioner measures growth, checks development, gives any vaccines that are due, and asks about feeding, sleep, safety, behavior and how the family is doing. The American Academy of Pediatrics sets out what each visit should cover in its Bright Futures schedule.

These visits are also when routine screening happens. Newborns are screened for a range of rare but treatable conditions through a heel-prick blood test and a hearing test before leaving the hospital. Later visits include developmental screening with a standard questionnaire, autism-specific screening at 18 and 24 months, checks of vision and hearing as children grow, and in the teen years questions about mood, substance use, sexual health and safety. Depending on your child's risks, the doctor may also recommend tests such as a blood lead test or a cholesterol check.

Under the Affordable Care Act, most private health plans must cover recommended preventive care for children, including well-child visits and vaccines, without a copay when you use an in-network provider. Medicaid and the Children's Health Insurance Program (CHIP) cover these visits for eligible children, and every state has a program. If cost has kept you from going, it is worth checking again what your child is entitled to.

• Bring your child's vaccination record and any notes on milestones or worries
• Write questions down beforehand; visits move quickly
• Mention changes at home, at school or in child care, which can affect health and behavior
• From the early teens, expect the doctor to spend part of the visit alone with your child

Vaccines: the routine schedule and catching up

Vaccines protect children against diseases that used to fill pediatric wards, including measles, whooping cough (pertussis), polio, Hib (a cause of meningitis) and pneumococcal infections. The CDC publishes a recommended schedule each year, and the American Academy of Pediatrics publishes its own, which your child's doctor will follow. Most vaccines are given in the first two years, with boosters before kindergarten and again around ages 11 to 12. Timing matters because many of these diseases are most dangerous in the very young, so the schedule aims to protect children before they are most likely to be exposed.

A few examples show how the schedule works. The MMR vaccine against measles, mumps and rubella is given as two doses, the first at 12 to 15 months and the second at 4 to 6 years. The HPV vaccine, which prevents several cancers later in life, is recommended at ages 11 to 12 and can be started as early as 9, because it works best when given well before any exposure. A yearly flu vaccine is recommended for children from 6 months of age.

Falling vaccination rates in some communities have allowed measles outbreaks to return in the US. Measles is one of the most contagious infections known and can cause pneumonia, brain swelling and death. If your child has missed doses, they can almost always be caught up without starting over, using the CDC catch-up schedule. The federal Vaccines for Children program provides vaccines at no cost to eligible children, including those on Medicaid, those without insurance and American Indian and Alaska Native children.

Side effects and safety

Most children have no reaction or a mild one: a sore, red spot where the shot went in, a low fever, or a day of fussiness. These usually pass within a day or two. Severe allergic reactions are rare and happen within minutes, which is why clinics ask you to wait briefly after vaccination and keep emergency treatment on hand. Vaccines are monitored continuously after approval, and your child's doctor can talk through any specific concern, including what is known about the safety of giving several vaccines at the same visit.

Growth and development

Growth is tracked by plotting weight, length or height and, in young children, head size on a growth chart. US doctors use the WHO growth charts for children under 2 and the CDC growth charts from age 2. A percentile tells you how your child compares with others of the same age and sex: a child on the 25th percentile for weight is heavier than about a quarter of children that age. There is no right percentile. What matters is that your child follows a roughly steady line. A child who drops across two or more major percentile lines, or stops gaining weight, needs a checkup to look for a cause.

Development covers how children move, communicate, play, learn and relate to others. The CDC's Learn the Signs. Act Early. program publishes milestone checklists for each age, from smiling at people around 2 months to walking, first words and pointing in the second year, and putting words together after that. Children vary a lot in when they reach individual milestones, so the checklists show what most children do by a given age. Missing one milestone is rarely cause for alarm on its own; a pattern of delays, or any loss of skills a child already had, needs prompt attention.

If you are worried, say so early rather than waiting to see whether your child catches up. For a speech delay, a hearing test is one of the first steps, because even mild hearing loss can hold back language. Every state runs an early intervention program for children under 3 with possible delays, which provides an evaluation at no cost and services that are free or low cost depending on the state. From age 3, your local public school district is responsible for evaluating children and providing special education services if they qualify. You can contact either directly; you do not need a doctor's referral.

• Track milestones with the CDC checklists or its free Milestone Tracker app
• Raise concerns about hearing, speech, eye contact or response to name early
• Compare your child with their own chart, not with siblings or friends
• Loss of skills at any age always needs a prompt checkup

Feeding and nutrition from baby to teen

For babies, breast milk or iron-fortified infant formula provides all the nutrition needed for about the first 6 months. Breastfed babies need a vitamin D supplement of 400 IU (10 mcg) a day from the first days of life, because breast milk is low in vitamin D; your child's doctor can advise on drops. Solid foods are usually introduced at around 6 months, when a baby can sit with support and shows interest. Current US guidance encourages introducing common allergenic foods, including peanut in an age-appropriate form such as thinned peanut butter, along with other first foods, rather than delaying them. Babies with severe eczema or an existing egg allergy should be checked by their doctor first.

A few foods are off-limits for babies. Honey should not be given before 12 months because of the risk of infant botulism. Whole cow's milk is introduced from 12 months, not before, and fruit juice is not recommended in the first year. Salt and added sugar should not be added to a baby's food. Whole nuts, whole grapes, popcorn, hard candy and chunks of hot dog are choking hazards for young children; cut grapes and hot dogs lengthwise and into small pieces.

From age 1 onward, children do best on the same broad pattern recommended for adults: plenty of vegetables, fruit, whole grains, protein foods and dairy or fortified alternatives, with water and milk as the main drinks. The Dietary Guidelines for Americans advise avoiding added sugars entirely before age 2 and keeping them under 10% of daily calories from age 2. Sugary drinks are the biggest single source of added sugar for many children. Children and teens aged 1 to 18 need 600 IU (15 mcg) of vitamin D a day, and many fall short.

Picky eating is a normal phase, especially between about 2 and 5. Children may need to be offered a new food many times before they accept it, and pressure tends to backfire. A useful split of responsibilities is that you decide what food is offered, when and where, and your child decides whether to eat and how much. Eating together as a family, even a few times a week, helps children learn by watching.

Sleep, screens and physical activity

Sleep drives growth, learning, mood and the immune system, and many US children do not get enough. Guidance endorsed by the American Academy of Pediatrics and used by the CDC recommends 12 to 16 hours in 24 hours, including naps, for babies aged 4 to 12 months; 11 to 14 hours for ages 1 to 2; 10 to 13 hours for ages 3 to 5; 9 to 12 hours for ages 6 to 12; and 8 to 10 hours for teens aged 13 to 18. A consistent bedtime, a calm wind-down routine and a dark, quiet bedroom help at every age. Teens naturally shift toward later sleep times, which collides with early school starts; protecting their sleep is worth the effort.

Screens matter mostly because of what they crowd out. The American Academy of Pediatrics advises avoiding screens other than video chatting for children under 18 months, and limiting screen use to about 1 hour a day of high-quality programming for ages 2 to 5, ideally watched together so you can talk about it. For older children and teens, the focus shifts to a family media plan: agreed limits that protect sleep, schoolwork, physical activity and time together. Devices out of bedrooms overnight and no screens in the hour before bed are two of the most useful rules.

Physical activity builds strong bones and muscles, supports a healthy weight, and is linked to better mood, attention and sleep. The Physical Activity Guidelines for Americans recommend that preschool children aged 3 to 5 be active throughout the day. Children and teens aged 6 to 17 should get 60 minutes or more of moderate-to-vigorous activity every day, including vigorous activity on at least 3 days a week and muscle-strengthening and bone-strengthening activity on at least 3 days a week each. Running, jumping, climbing and playing sports all count.

For younger children, activity works best as play rather than exercise. For older children, variety helps: playing several sports rather than specializing early in one lowers the risk of overuse injuries and burnout. Walking or biking to school, family walks and active weekends add up. Avoid framing activity as a way to lose weight, which can make children self-conscious; present it as something that makes them stronger and feels good.

Common illnesses and fever

Young children commonly catch several colds a year, especially in their first years of child care or school, as their immune systems meet new viruses. A cold usually lasts 7 to 10 days, and a cough can linger for a couple of weeks after other symptoms settle. Most sore throats are viral, but strep throat is bacterial and needs a test to confirm it before antibiotics are given. Many ear infections get better on their own, and your child's doctor may suggest watchful waiting with pain relief before prescribing an antibiotic. Antibiotics do nothing for viral illnesses and can cause diarrhea, rashes and resistance.

A fever is a temperature of 100.4°F (38°C) or higher. In itself it is usually a sign that the body is fighting an infection, not a danger. The big exception is age: any fever of 100.4°F (38°C) or higher in a baby under 3 months needs a call to the doctor right away, because young babies can become seriously ill quickly and show few other signs. For older children, how your child looks and behaves matters far more than the number. A child who is drinking, still plays a little when the fever comes down, and wakes easily is reassuring.

Treat fever for comfort rather than to bring the number down. Acetaminophen (Tylenol) can be used, and ibuprofen can be used from 6 months; dose by your child's weight using the device that comes with the medicine, and do not alternate the two without your doctor's advice. Never give aspirin to children or teens, because it is linked to Reye's syndrome, a rare but serious condition affecting the liver and brain. The FDA advises against over-the-counter cough and cold medicines for children under 2, and many product labels say not to use them under age 4.

Rashes and the press test

Most childhood rashes are caused by viruses and fade on their own. Chickenpox causes itchy blisters in crops and is contagious until all of them have crusted over. Hand, foot and mouth disease causes mouth sores and spots on the hands and feet and is usually mild. Fifth disease, sometimes called slapped cheek, causes bright red cheeks; tell your doctor if you are pregnant and have been exposed. The one rash that changes everything is one made of tiny red or purple spots that do not fade when you press a clear glass against them. Especially with fever, this can signal a serious bloodstream infection and needs emergency care.

Dehydration

Vomiting, diarrhea and fever all increase fluid loss, and young children dehydrate faster than adults. Offer small, frequent sips, and for babies keep breastfeeding or giving formula. An oral rehydration solution from the pharmacy is better than juice or sports drinks for replacing lost fluids. Signs of dehydration include fewer wet diapers or trips to the bathroom, a dry mouth, no tears when crying, sunken eyes, and unusual drowsiness. A child with these signs needs to be seen the same day.

Teeth, eyes and ears

Tooth decay is one of the most common chronic conditions of childhood, and it is largely preventable. Start brushing as soon as the first tooth appears, using fluoride toothpaste: a smear about the size of a grain of rice for children under 3, and a pea-sized amount from 3 to 6. Brush twice a day and supervise brushing until your child can do it well, usually around age 7 or 8. The American Dental Association and American Academy of Pediatrics recommend a first dental visit by age 1. Your child's doctor or dentist may also apply fluoride varnish to the teeth, a quick, painless step that helps prevent decay.

Avoid putting a baby to bed with a bottle of milk, formula or juice, which bathes the teeth in sugar overnight. Sugary drinks and frequent snacking on sticky or sweet foods through the day give decay-causing bacteria a steady supply, so keep sweet treats to mealtimes and offer water between meals. Ask your dentist about sealants for the back teeth, which protect the grooves where decay often starts.

Vision and hearing problems can quietly affect learning and behavior. Babies have their hearing screened at birth, and vision and hearing are checked at well-child visits as children grow. Signs worth raising include squinting, sitting very close to the TV, an eye that turns in or out, frequent eye rubbing, not responding to sounds, or speech that is not developing as expected. Children rarely complain that they cannot see well, because they assume everyone sees the way they do.

Mental health and emotional well-being

Many lifelong mental health conditions begin in childhood or the teen years, and getting help early can change their course. The most common include anxiety, depression, attention-deficit/hyperactivity disorder (ADHD) and behavior disorders. Children often cannot name what they are feeling, so the signs show up in behavior: stomachaches or headaches with no clear cause, trouble sleeping, irritability, clinginess, avoiding school, losing interest in friends or activities, or a drop in grades. In teens, watch for withdrawal, big changes in eating or sleeping, risky behavior and talk of hopelessness.

Everyday life does much of the protective work. Regular sleep, physical activity, time outdoors, family meals and at least one trusted adult to talk to all support mental health. When your child is struggling, ask open questions and listen without rushing to fix things or dismiss the feeling. Asking directly whether a young person has thought about hurting themselves does not put the idea in their head; it gives them permission to tell you.

Your child's doctor is a good place to start, and the US Preventive Services Task Force recommends screening for anxiety in children and teens aged 8 to 18 and for depression in teens aged 12 to 18. School counselors and psychologists can also help and may be able to arrange support in class. Do not wait for a formal diagnosis before getting support, and do not promise a young person to keep a disclosure secret if they are in danger. The 988 Suicide & Crisis Lifeline is available to anyone, of any age, by calling or texting 988 at any hour.

Social media and teens

Online life brings real benefits, including connection and information, alongside risks such as cyberbullying, contact from strangers, harmful content and sleep loss. Talk with your teen about what they do online, agree on limits together, and keep devices out of bedrooms overnight. Watch for distress around device use, secrecy about new contacts, or sudden changes in mood after time online, and make it clear they can come to you if something goes wrong without automatically losing their phone.

Safety at home, on the road and in the water

Injuries, not illnesses, are among the leading causes of death in US children, and most are predictable and preventable. For babies, safe sleep is the priority: the American Academy of Pediatrics recommends placing babies on their back for every sleep, on a firm, flat surface in their own crib, bassinet or play yard, with no pillows, bumpers, blankets or soft toys. Room-sharing without bed-sharing is recommended, ideally for at least the first 6 months. Never sleep with a baby on a sofa or armchair.

Drowning is a leading cause of death for children aged 1 to 4. It is quick and silent, and it can happen in bathtubs and buckets as well as pools. Never leave young children alone near water, even for a moment, fence home pools on all four sides with a self-closing gate, and teach water safety and swimming skills. Use a properly fitted life jacket on boats.

In the car, NHTSA and the American Academy of Pediatrics advise keeping children in a rear-facing car seat for as long as possible, until they reach the top height or weight limit for that seat, then a forward-facing seat with a harness, then a booster seat until the adult seat belt fits properly, usually when a child is about 4 feet 9 inches (145 cm) tall and between 8 and 12 years old. Children under 13 should ride in the back seat. Many fire departments and hospitals offer free car seat checks.

At home, store medicines, cleaning products, laundry detergent packets and alcohol locked up and out of reach. Button batteries are an emergency if swallowed, because they can burn through tissue within hours, so keep them and devices with loose battery covers away from children. Anchor furniture and TVs to the wall, install safety gates and window guards, keep hot drinks out of reach, and set your water heater to 120°F (49°C) or lower to prevent scalds. Firearm injuries are now a leading cause of death for US children and teens; if there is a gun in the home, store it unloaded and locked, with ammunition locked separately, and ask about guns in homes your child visits.

• Save Poison Control, 1-800-222-1222, in your phone and post it at home
• Cool a burn under cool running water for about 20 minutes; no ice, butter or creams
• Use a helmet for biking, scooters and skating
• Use sunscreen of SPF 30 or higher on children over 6 months, and keep younger babies out of direct sun

Children with long-term conditions and special health needs

Some children live with a long-term condition such as asthma, type 1 diabetes, food allergy, epilepsy or a developmental disability. The day-to-day goal is the same as for any child: to grow, learn, play and take part fully, with the condition managed well enough that it fades into the background. A written care plan agreed with your child's doctor, shared with school and child care, makes this much easier. For asthma that means an asthma action plan; for severe allergy it means an emergency plan with epinephrine auto-injectors available wherever your child is.

Federal law gives children with disabilities and health conditions the right to support at school. A 504 plan sets out accommodations, such as access to medicine, snacks or rest breaks, for a child whose condition affects school life. An Individualized Education Program (IEP) provides special education services for children who qualify. Ask the school in writing for an evaluation if you think your child needs either.

As teens with long-term conditions grow up, they gradually need to take over their own care: knowing their medicines, booking appointments, and speaking to the doctor on their own. Starting this transition in the early teens, rather than at 18, gives them time to learn while you are still close by. Ask your child's doctor when and how they plan to move your teen to adult care.

Working with your child's doctor and a yearly plan

A good relationship with a pediatrician or family doctor makes everything easier. Before a visit, jot down the two or three things that matter most to you, along with any patterns you have noticed: when symptoms happen, how long they last, what helps. Photos of a rash or a short video of an unusual movement or breathing pattern can be very useful, since symptoms often vanish in the exam room. If you do not understand an explanation, ask again; if you feel something is wrong despite reassurance, say so clearly. You know your child best.

Know your options for after-hours care before you need them. Many practices have a nurse line or an after-hours number, and urgent care centers can handle many minor illnesses and injuries. The emergency room is for serious or life-threatening problems, and 911 is for emergencies where your child needs help immediately. Knowing the difference ahead of time saves stressful decisions at 2 a.m. Write the after-hours number next to Poison Control on the fridge.

Teens should be given private time with their doctor. This is standard practice and gives them space to ask about mood, relationships, sexual health or substance use honestly. Confidentiality rules for minors vary by state, and doctors will involve parents if a teen is at serious risk. Encourage your teen to use this time well and to keep a list of their own questions.

• Once a year: well-child visit, vaccines checked against the CDC schedule, and a flu vaccine each fall
• Twice a year: dental checkups, or as your dentist advises
• Every season: check car seat fit as your child grows, and review medicine storage
• Ongoing: protect sleep, aim for 60 minutes of activity a day for school-age children, and keep screens out of bedrooms at night
• As needed: raise worries about growth, development, mood or behavior early rather than waiting

Every guide in this topic

• Childhood Vaccinations: Sorting the Evidence From the Noise
• Fever in Children: What Published Guidance Supports
• Childhood Nutrition: Sorting the Evidence From the Noise
• Children and Screens: Sorting the Evidence From the Noise
• Childhood Activity: What the Evidence Actually Says
• Childhood Rashes: What Published Guidance Supports
• What the Guidance Really Says About Child Mental Health
• Growth and Development: What the Evidence Actually Says
• Common Childhood Infections: What the Evidence Actually Says
• Child Safety at Home: What Published Guidance Supports

Frequently asked questions

How high a fever is dangerous for a child?

For a baby under 3 months, any temperature of 100.4°F (38°C) or higher needs a call to the doctor right away. For older children, the number matters less than how your child looks and acts. A child who is drinking, alert and plays a little when the fever drops is usually fine. Seek care urgently for a child who is limp, hard to wake, breathing fast, or has a rash that does not fade when pressed.

Can my child catch up on missed vaccines?

Yes. Missed doses can almost always be caught up without restarting the series. The CDC publishes a catch-up schedule that your child's doctor uses to plan the remaining doses as quickly and safely as possible. Bring any records you have. If cost is a barrier, ask whether your child qualifies for the Vaccines for Children program, which provides vaccines at no cost to eligible children.

Is it safe to give acetaminophen and ibuprofen together?

Do not alternate or combine them unless your child's doctor advises it, because it increases the chance of dosing mistakes. Acetaminophen (Tylenol) can be used for comfort at any age with the right dose, and ibuprofen from 6 months. Always dose by weight using the measuring device that comes with the medicine. Never give aspirin to a child or teen because of the risk of Reye's syndrome.

My toddler is a very picky eater. Should I worry?

Picky eating is common and usually a normal phase between about 2 and 5. Keep offering a range of foods without pressure, including small amounts of new foods alongside familiar ones; acceptance can take many tries. Avoid filling up on milk, juice or snacks between meals. Talk to your child's doctor if your child is losing weight, dropping across growth chart lines, eats very few foods, or gags or chokes often.

How much screen time is OK?

The American Academy of Pediatrics advises avoiding screens other than video chatting under 18 months and about 1 hour a day of high-quality programming for ages 2 to 5, ideally watched together. For older children, rather than a single number, protect sleep, schoolwork, activity and family time first. Keep devices out of bedrooms overnight and avoid screens in the hour before bed.

When should my child see a dentist for the first time?

The American Dental Association and American Academy of Pediatrics recommend a first dental visit by age 1, or within six months of the first tooth appearing. Start brushing with fluoride toothpaste as soon as the first tooth comes in: a rice-grain-sized smear under 3 and a pea-sized amount from 3 to 6. Ask your child's doctor or dentist about fluoride varnish.

What should I do if my child swallows a button battery?

Treat it as an emergency. Call 911 or go to the emergency room immediately, even if your child seems fine, because a button battery can cause severe burns inside the body within hours. Do not make your child vomit. You can also call Poison Control at 1-800-222-1222 for advice on the way, but do not delay getting to emergency care.

When should my child switch from a car seat to a booster seat?

Keep your child in each stage for as long as the seat allows. Use a rear-facing seat until your child reaches its height or weight limit, then a forward-facing seat with a harness until they outgrow that. Move to a booster seat after that, and keep using it until the adult seat belt fits properly, usually at about 4 feet 9 inches tall. Children under 13 should ride in the back seat.

How do I know if my child's worries or moods need professional help?

Look at how long it has lasted and how much it gets in the way. Feelings that persist for weeks, or that stop your child going to school, seeing friends, sleeping or eating normally, deserve a conversation with their doctor or school counselor. Seek help promptly for any talk of self-harm or wanting to die. You can call or text 988 at any hour, and call 911 for immediate danger.

Does my child need a vitamin supplement?

Breastfed and partly breastfed babies need 400 IU (10 mcg) of vitamin D a day from the first days of life, and your child's doctor can advise when to stop. Most older children who eat a varied diet do not need a multivitamin, though some need extra vitamin D or iron. Ask your child's doctor before giving supplements, keep them locked away, and remember that iron is dangerous in overdose.

When to speak to a doctor

Call your child's doctor right away for any fever of 100.4°F (38°C) or higher in a baby under 3 months, and see the doctor promptly for signs of dehydration, a child who is getting worse instead of better, poor growth, loss of skills they once had, or ongoing changes in mood or behavior. Call 911 for difficulty breathing, a seizure, choking that does not clear, a rash that does not fade when pressed, blue or mottled skin, or a child who is limp, unresponsive or very hard to wake. Call 911 or go to the ER immediately if a button battery may have been swallowed. Call Poison Control at 1-800-222-1222 for any suspected poisoning. If a child or teen talks about suicide or self-harm, call or text 988, and call 911 if they are in immediate danger.

Where this comes from

• CDC — Child and Adolescent Immunization Schedule by Age
• American Academy of Pediatrics — Fever and Your Baby
• CDC — Learn the Signs. Act Early.
• Dietary Guidelines for Americans — Dietary Guidelines for Americans, 2020-2025
• NIH Office of Dietary Supplements — Vitamin D Fact Sheet for Consumers
• HHS — Physical Activity Guidelines for Americans, 2nd edition
• CDC — About Sleep
• NHTSA — Car Seats and Booster Seats
• Poison Control — Button Batteries
• National Institute of Mental Health — Children and Mental Health

How this page was put together

Every figure, recommendation and warning above is taken from the guidance named in Where this comes from. Nothing on this page is inferred, summarized or generalized beyond what those bodies publish: where they give a number, it is their number, and where they are silent, so are we. Pages are rebuilt whenever the underlying record changes. Sign-off by a named clinician, where it has happened, is shown at the top of the page along with the date.

Medical disclaimer

This article is general information, not medical advice. It cannot account for your own history, medication or circumstances. Always speak to your doctor, pharmacist or another qualified health professional before making changes that affect your treatment, and never delay seeking medical advice because of something you have read here. In an emergency, call 911.