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Mononucleosis (Mono)

Mononucleosis (mono) is caused by the Epstein-Barr virus. Mono is best known for causing swollen glands and tiredness. But it can cause other symptoms as well. Mono is most likely to occur in older children, teens, and those in their early to mid-20s. Younger children are much less likely to get as sick if they are exposed to the virus. Most people with mono recover without any problems. But the illness can take a long time to go away. In some cases, mono can cause prolonged tiredness (fatigue) or problems with the liver, spleen, or heart. So it's important to diagnose mono and to watch your child carefully.

How mono is spread

Mono can be easily spread from an infected person's saliva to an uninfected person by:

  • Drinking and eating after them

  • Sharing a straw, cup, toothbrushes, and eating utensils

  • Kissing and close contact

  • Handling toys that had contact with a child's drool

Symptoms of mono

Common symptoms of mono include:

  • Tiredness, weakness

  • Fever

  • Sore throat

  • Sore or swollen lymph nodes in the neck or armpits

  • Swollen tonsils

  • Rash

  • Sore muscles or stiffness

  • Headache

  • Loss of appetite, upset stomach (nausea)

  • Dull pain in the stomach area

  • Enlarged liver and spleen

  • Puffy eyes

  • Sensitivity to light

Treating mono

Mono is a viral infection. So antibiotics won’t cure it. Your child's healthcare provider may prescribe medicines to help ease your child's pain or discomfort. The best treatment for mono is rest. A child with mono should also drink lots of fluids. To help your child feel better and recover sooner:

  • Make sure your child gets enough rest.

  • Give plenty of fluids.

  • The spleen may become enlarged with mono. Your child may need to not do any contact sports or heavy lifting for a while. This is to prevent injury to the spleen. Discuss this with your child's healthcare provider.

  • Treat fever, sore throat, headache, or aching muscles with acetaminophen or ibuprofen. Your child's healthcare provider or nurse can help you with the correct dose. At times the provider will prescribe other treatments such as steroids to control symptoms. Don’t give aspirin (or medicine that contains aspirin) to a child younger than age 19 unless directed by your child’s provider. Taking aspirin can put your child at risk for Reye syndrome. This is a rare but very serious disorder. It most often affects the brain and the liver.

Symptoms often last for a few weeks. But they can sometimes last for 1 to 2 months or longer. Even after symptoms go away, your child may be tired or weak for some time.

Preventing the spread of mono

While you’re caring for a child with mono:

  • Wash your hands with warm water and soap often, especially before and after tending to your sick child. Wash your hands for at least 15 to 30 seconds each time.

  • Watch your own health and that of other family members who might be at risk.

  • Clean dishes and eating utensils used by a sick child separately in very hot, soapy water. Or run them through the dishwasher.

When to get medical care

Call your child’s healthcare provider right away if your otherwise healthy child:

  • Has a fever (see "Fever and children" below)

  • Has had a seizure caused by the fever

  • Has difficult or very fast breathing

  • Can’t be soothed or shows signs of being grouchy or restless

  • Seems abnormally drowsy, listless, or unresponsive

  • Has trouble eating, drinking, or swallowing

  • Stops breathing, even for an instant

  • Shows signs of severe chest, neck, or belly pain

Fever and children

Always use a digital thermometer to check your child’s temperature. Never use a mercury thermometer.

For infants and toddlers, be sure to use a rectal thermometer correctly. A rectal thermometer may accidentally poke a hole in (perforate) the rectum. It may also pass on germs from the stool. Always follow the product maker’s directions for proper use. If you don’t feel comfortable taking a rectal temperature, use another method. When you talk to your child’s healthcare provider, tell him or her which method you used to take your child’s temperature.

Here are guidelines for fever temperature. Ear temperatures aren’t accurate before 6 months of age. Don’t take an oral temperature until your child is at least 4 years old.

Infant under 3 months old:

  • Ask your child’s healthcare provider how you should take the temperature.

  • Rectal or forehead temperature of 100.4°F (38°C) or higher, or as directed by the provider.

  • Armpit temperature of 99°F (37.2°C) or higher, or as directed by the provider.

Child age 3 to 36 months:

  • Rectal, forehead, or ear temperature of 102°F (38.9°C) or higher, or as directed by the provider.

  • Armpit temperature of 101°F (38.3°C) or higher, or as directed by the provider.

Child of any age:

  • Repeated temperature of 104°F (40°C) or higher, or as directed by the provider.

  • Fever that lasts more than 24 hours in a child under 2 years old. Or a fever that lasts for 3 days in a child 2 years or older.

Online Medical Reviewer: Barry Zingman MD
Online Medical Reviewer: Marianne Fraser MSN RN
Online Medical Reviewer: Raymond Kent Turley BSN MSN RN
Date Last Reviewed: 6/1/2019
© 2000-2021 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.