What is mononucleosis?


Mononucleosis in children: Overview

Mononucleosis (mono) is an infection. It's usually caused by the Epstein-Barr virus. People get it through contact with saliva and with mucus from the nose and throat. A child can get mono from kissing an infected person. Or a child may get it after sharing a glass, fork, or spoon with someone who has mono.

Symptoms include a fever and a very sore throat. Your child may also have swollen glands and tonsils and feel weak and tired.

Sometimes the virus causes the spleen to swell. The spleen is an organ in the upper left side of the belly. If it ruptures, it's an emergency. So it's important for your child to avoid rough sports or challenging activities while your child has mono. These can put extra pressure on the spleen.

It takes time to recover from mono. The lymph nodes in your child's neck may be larger than normal for a while. Most children get better after 2 to 4 weeks. But it could take several more weeks before your child's normal energy is back. Lots of rest will help your child feel better.


Mononucleosis, or "mono," is a common illness caused by a virus. It's often seen in teens and young adults. It can cause a bad sore throat, swollen neck glands, and fever. Some people feel tired and weak for weeks or months after getting sick.

Mono usually goes away on its own, but rest and good self-care can help you feel better. Mono is nicknamed "the kissing disease" because that's one way the virus is spread. If you have mono, don't kiss anyone or share things like drinking glasses, eating utensils, or toothbrushes.

What are the symptoms of mononucleosis (mono)?

The most common symptoms of mono include fever, sore throat, swollen lymph nodes, and feeling tired and weak. Mono can also cause pain in the upper left part of your belly, which may mean that the spleen is enlarged. Symptoms usually start 4 to 6 weeks after you're exposed to the virus.

How is mononucleosis (mono) treated?

Treatment for mono usually involves self-care measures like rest and over-the counter medicines to reduce pain and fever. In severe cases, corticosteroids may be used to reduce swelling of the throat, tonsils, or spleen.

How is mononucleosis (mono) diagnosed?

Your doctor will ask you questions about your symptoms and will examine you. You may also need blood tests to check for mono and signs of mono. Blood tests can also help rule out other causes of your symptoms.

How can you care for your child who has mononucleosis?

  • Have your child rest and stay in bed as much as possible until they feel well enough to be up.
  • Have your child drink plenty of fluids. Choose water and other clear liquids until your child feels better.
  • Be safe with medicines. Have your child take medicines exactly as prescribed. Call your doctor if you think your child is having a problem with a medicine.
  • Give your child acetaminophen (Tylenol) or ibuprofen (Advil, Motrin) for fever or pain. Be safe with medicines. Read and follow all instructions on the label.
    • Do not give your child two or more pain medicines at the same time unless the doctor told you to. Many pain medicines have acetaminophen, which is Tylenol. Too much acetaminophen (Tylenol) can be harmful.
    • Do not give aspirin to anyone younger than 20. It has been linked to Reye syndrome, a serious illness.
  • Do not let your child play contact sports or lift anything heavy for 4 weeks. These activities can increase the chance that the spleen may rupture.
  • Try not to spread the virus to others. Make sure your child does not kiss or share dishes, glasses, eating utensils, or toothbrushes. It's hard to know how long your child can spread the virus. This is because your child could have it long after symptoms go away.

How does mononucleosis (mono) spread?

The virus that usually causes mono—the Epstein-Barr virus (EBV)—can be spread through:

  • Intimate contact or sharing of saliva. (A brief kiss on the lips isn't likely to spread EBV. It's spread when saliva from an infected person gets into another person's mouth.)
  • Mucus from the nose and throat, and sometimes tears.
  • Sharing things like drinking glasses, eating utensils, or toothbrushes with a person who is infected with EBV.

EBV isn't spread by casual contact. You can live in the same house with a person who has mono and never be infected with the virus. But a person who has a weakened immune system may be at higher risk for mono.

You can pass EBV to others for several weeks or months during and after the time you are first infected with EBV. The virus can also become active and spread to others from time to time throughout your life.

What is mononucleosis (mono)?

Mononucleosis (mono) is a common illness caused by a virus. It can start with a sore throat and swollen glands. And then it can leave you feeling tired and weak for weeks or months. Mono goes away on its own, but rest and good self-care can help you feel better.

What causes mononucleosis (mono)?

Mono usually is caused by the Epstein-Barr virus (EBV). It's most often seen in teens and young adults. Children can get the virus, but it often goes unnoticed because their symptoms are mild. Older adults usually don't get mono. That's because they have immunity to the virus.

Mononucleosis in children: When to call

Call 911 anytime you think your child may need emergency care. For example, call if:

  • Your child passes out (loses consciousness).

Call your doctor now or seek immediate medical care if:

  • Your child has new or worse belly pain.
  • Your child has signs of needing more fluids. This means your child has sunken eyes and a dry mouth and is passing only a little urine.
  • Your child is dizzy or light-headed or feels like he or she may faint.
  • Your child cannot swallow fluids.

Watch closely for changes in your child's health, and be sure to contact your doctor if:

  • Your child does not get better as expected.

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