Mononucleosis (Mono) Symptoms in Kids

Symptoms of mono are similar to the flu and strep throat

Mono symptoms in kids include flu-like symptoms, fever, and swollen lymph nodes. However, many kids show no symptoms of mono.

Infectious mononucleosis (also called "mono"), is a viral illness that typically spreads through saliva. It is common in teenagers and college students. Kids can easily get mono if they share a water bottle with a sick friend or are kissed by a family member with the infection.

Mono is spread by saliva and other bodily fluids such as blood and semen. It is usually caused by the Epstein-Barr virus (EBV) and sometimes the cytomegalovirus (CMV). Once your child recovers from mono, the virus stays dormant in their body.

While many of the symptoms are similar to mono in adults, the virus can present differently in children. 

This article will go over mono symptoms in kids. You'll also learn how mono is diagnosed in kids, how children are treated for mono, and tips for preventing mono.

Teenage girl sick in bed

Justin Paget / Getty Images

Frequent Symptoms of Mono in Kids

It’s common to mistake your child’s mono symptoms for the flu or strep throat. Since mononucleosis is usually associated with teens and college-age kids, you may not think that a child can get mono.

When a child is infected with mono, they won't have symptoms right away. It usually takes two to four weeks for the symptoms to start.

Once they show up, mono symptoms can last several weeks. If your child does not show any improvement after a few days, talk with your healthcare provider about a possible mono diagnosis. 

While each case of mono is unique, some of the most common symptoms include:

  • Swollen lymph nodes: Swollen lymph nodes are a common symptom of mono. When your child’s lymph nodes are swollen, it means their immune system is fighting off an infection. 
  • Fever: A mild to moderate fever is another common mono symptom. Your healthcare provider will most likely recommend giving your child acetaminophen or ibuprofen to manage the fever and discomfort. 
  • Fatigue: While most mono symptoms last two to four weeks, the fatigue can linger for weeks to months. If your child is so tired that they no longer want to get out of bed or eat meals, talk with your practitioner.
  • Sore throat: Most children with mono report a sore throat. This may be due to swelling of the lymph nodes and tonsils, making swallowing painful. 
  • Body aches: It’s common for children and teens to experience muscle aches with mono. Encourage rest, liquids, and pain medicine if needed. 
  • Loss of appetite: Many children lose their appetite when they are ill with mono. This could be due to fatigue or painful swallowing. Encourage your child to drink as much fluid as possible to prevent dehydration.
  • Enlarged spleen: It’s common for children and teens with mono to have an enlarged spleen during the illness. When the spleen is enlarged, it may start to filter out normal red blood cells and platelets, leading to their low levels in the blood. In most cases, the spleen returns to its normal size on its own.
  • Swollen liver: It’s possible for children with mono to have a mildly inflamed liver. This usually resolves on its own once they start feeling better. If you notice a yellowing of your child’s eyes or skin, known as jaundice, call your healthcare provider. 

How Long Is Mono Contagious in Kids?

A child with mono can spread the infection to others for as long as they are having symptoms. That means they could be contagious for weeks if not months.

They might also be able to keep spreading the virus after they get better, but studies haven't found a definitive answer for how long mono remains contagious once a person heals.

It's also possible for people to be carriers of the virus that causes mono. This means that they get infected and can spread the virus to other people without ever feeling sick themselves.

Rare Symptoms of Mono in Kids

Mono can be serious in children. Most people are familiar with the common symptoms of mono like fatigue and fever, but you may not be aware of these rare symptoms:

  • Anemia: Mild anemia can occur when your child has mono, but it generally improves on its own within one to two months. This is usually the result of an inflamed spleen.
  • Thrombocytopenia: It’s possible for your child to experience a low platelet count during a mono illness. Platelets are the cells responsible for clotting your blood. This also usually resolves on its own. 
  • Difficulty breathing: You may notice that your child’s tonsils appear swollen. This is normal during mono. In rare cases, the tonsils can become so swollen that they begin to block your child’s airway. Any difficulty breathing requires emergency treatment. 

How Mono in Kids Is Diagnosed

Diagnosing mono in children is the same as diagnosing it in teens and adults. Your child's provider will ask you about any mono symptoms, do an exam, and may order some blood tests.

Here's what your child's provider will check for to diagnose mono:

  • Swollen tonsils and/or lymph nodes
  • An enlarged liver and/or spleen
  • Signs of infection on a blood test (such as a high white blood cell count)

Mono Treatment for Kids

Kids with mono need to focus on resting and staying hydrated and nourished.

Since mono is caused by a virus, antibiotics won't help your child get better. That said, over-the-counter pain and fever medicine like Motrin (ibuprofen) might help with their symptoms.

A child with mono may need to take it easy for several weeks or even a month. Their provider might also put limits on how active they can be while they're sick, especially if their spleen is enlarged.

When to Seek Medical Attention

If your child has mono symptoms, like a fever, swollen lymph nodes, and fatigue, they'll need to get medical care. Remember that mono symptoms usually last longer than those of a cold or the flu.

If your child is not starting to feel better a few days after symptom onset, call your pediatrician. Your provider's office staff will help you determine if you should bring your child into the clinic or opt for a telehealth visit. 

Your pediatrician will start by asking about your child's symptoms and will then perform a physical exam to look for signs of infection. They may also ask you to go to the lab for blood tests, such as a white blood cell count or monospot test, to confirm the diagnosis.

Even after your child has been diagnosed with mono, don’t hesitate to call your provider if their symptoms change or if you are concerned. 

Any sign of a serious complication such as difficulty breathing or confusion needs to be evaluated immediately.

Preventing Mono in Kids

Your child can't get vaccinated against mono like they could the flu. That said, you can protect your child from mono by practicing many of the habits that prevent other infectious illnesses, like colds and COVID-19.

Here are a few steps you can take to prevent mono:

  • Teach your child how to wash their hands properly and make sure they wash their hands frequently—especially before they eat and after they use the bathroom.
  • Tell your child not to share cups, water bottles, utensils, toothbrushes, or any other item they would put in their mouth with other people (e.g., classmates, friends, family members).
  • Keep your child away from people who are sick as much as possible. If someone in your family gets mono, try to keep your child separated from them. At the very least, make sure they don't hug and kiss the person until they are well. If everyone is in close quarters, wearing face masks can be helpful.
  • Make sure that the surfaces and objects for eating are clean. Wash them with hot water and soap, run them through the dishwasher, or boil them. If your child or another member of your family is sick, you can also have them use disposable utensils and dishes until they're better.
  • Launder bedding and clothes in hot water, especially after someone has been sick.


Mononucleosis or "mono" is a common viral infection. It's usually associated with teens and college kids, but children can get mono too. At first, the symptoms of mono in kids can seem like a cold or the flu. However, they tend to last several weeks. There's no specific medicine to treat mono in kids—mostly, they'll just need to rest.

A Word From Verywell

The long list of potential symptoms and complications of mono can be overwhelming for any parent. It’s helpful to remember that most children and teens who are diagnosed with mono experience swollen lymph nodes, fever, and fatigue, and these symptoms usually resolve on their own. Talk with your healthcare provider if you suspect that your child has become ill with mono, and stay in close contact with them if your child’s symptoms start to change. 

Frequently Asked Questions

  • How does a kid get mono?

    Mono is spread through body fluids. Kids to pick up mono if they're exposed to the saliva of someone who is sick. For example, a child could get mono from sharing a water bottle with a sick friend.

  • How long does mono last in a child?

    Children with mono won't start feeling sick for four to six weeks after they've caught the virus. Once they start feeling unwell, the symptoms of mono can last anywhere from two weeks to over a month.

  • How long is mono contagious?

    A child with mono is contagious for at least as long as they have symptoms, which can last for months. That said, some never develop symptoms but are still contagious.

8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Centers for Disease Control and Prevention. About Epstein-Barr virus (EBV).

  3. Nemours Children's Health. How Long Is Mono Contagious?.

  4. American Academy of Pediatrics. Mononucleosis.

  5. Wu Y, Ma S, Zhang L, Zu D, Gu F, Ding X, Zhang L. Clinical manifestations and laboratory results of 61 children with infectious mononucleosis. J Int Med Res. 2020;48(10):300060520924550. doi:10.1177/0300060520924550

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  7. Centers for Disease Control and Prevention (CDC). About Infectious Mononucleosis.

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By Carrie Madormo, RN, MPH
Carrie Madormo, RN, MPH, is a health writer with over a decade of experience working as a registered nurse. She has practiced in a variety of settings including pediatrics, oncology, chronic pain, and public health.