Children's Health and Wellness

Infectious Mononucleosis (Mono) in Teens and Young Adults

What is infectious mononucleosis in teens and young adults?

Infectious mononucleosis is a contagious illness. It’s common in teens and young adults. It is also known as mononucleosis, mono, glandular fever, or the “kissing disease.”

What causes mono in a teen or young adult?

Mono is often caused by the Epstein-Barr virus (EBV). It may also be caused by cytomegalovirus (CMV). Both viruses are members of the herpes simplex virus family.

Mono is most often spread by contact with infected spit (saliva). But it can also be spread through blood or other body fluids. It's hard to keep it from spreading because even people with no symptoms can carry the virus in their saliva and infect other people.

What are the symptoms of mono in a teen or young adult?

Most healthy people who get the CMV virus have few or no symptoms. Some may develop symptoms. EBV causes symptoms more often.

Symptoms of mono can take between 4 to 6 weeks to appear. They can last for weeks or months. They usually don’t last beyond 4 months. Tiredness and trouble thinking may last for months longer.

The most common symptoms of mono include:

  • Fever
  • Headache
  • Swollen lymph glands in the neck, armpits, and groin
  • Long periods of tiredness and muscle aches
  • Sore throat because of enlarged tonsils (tonsillitis). This can make it hard to swallow.
  • Enlarged spleen
  • Mild liver damage that can cause short-term yellowing of the skin and eyes (jaundice)

Once a child gets mono, the virus says inactive in the body for life but rarely develops symptoms of mono. 

The symptoms of mono can be like other health conditions. Make sure your child sees his or her healthcare provider for a diagnosis.

How is mono diagnosed in a teen or young adult?

The healthcare provider will ask about your child’s symptoms and health history. The provider will give your child a physical exam. The symptoms may be enough to diagnose mono. The diagnosis may be confirmed with blood tests for:

  • White blood cell count
  • Antibodies
  • Liver function

How is mono treated in a teen or young adult?

Treatment will depend on your child’s symptoms, age, and general health. It will also depend on how severe the condition is.

Prescriptions medicines are rarely needed in the treatment of mono. Because mono is caused by a virus, antibiotics will not help your child get better. In rare cases in which swelling of the throat and tonsils are making breathing hard, your child may need corticosteroids. If breathing becomes difficult, your child should see an ear, nose, and throat doctor (otolaryngologist). In most cases of mono, care to ease symptoms is all that is needed.

To ease symptoms, help your child:

  • Get lots of rest
  • Drink plenty of fluids to stay hydrated
  • Take over-the-counter medicine for fever and discomfort

What are possible complications of mono in a teen or young adult?

The spleen may enlarge because of the virus. The spleen is then at risk of rupture if your child is injured or in an accident. To protect the spleen, your child should not play any contact sports until fully recovered.

Both EBV and CMV stays in a person's cells for life, even after the symptoms of the virus are gone. The virus can become active again, but it usually doesn't cause symptoms. Most healthy people who get the CMV virus have no long-term health effects.

When should I call my teen’s or young adult’s healthcare provider?

Call the healthcare provider if your teen or young adult has:

  • Symptoms that don’t get better, or get worse
  • New symptoms

Key points about mono in teens and young adults

  • Infectious mononucleosis (mono) is often caused by the Epstein-Barr virus (EBV). It may also be caused by cytomegalovirus (CMV). 
  • Mono is most often spread by contact with infected spit (saliva).
  • Symptoms of mono can take between 4 to 6 weeks to appear. They can last for weeks or months. The most common symptoms of mono include fever, headache, swollen lymph glands, and sore throat.
  • The spleen may enlarge because of the virus. It’s then at risk of rupture if your child is injured or in an accident.
  • Both EBV and CMV stays in a person's cells for life, even after the symptoms of the virus are gone. The virus can become active again, but it usually doesn't cause symptoms.

Next steps

Tips to help you get the most from a visit to your child’s healthcare provider:

  • Know the reason for the visit and what you want to happen.
  • Before your visit, write down questions you want answered.
  • At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you for your child.
  • Know why a new medicine or treatment is prescribed and how it will help your child. Also know what the side effects are.
  • Ask if your child’s condition can be treated in other ways.
  • Know why a test or procedure is recommended and what the results could mean.
  • Know what to expect if your child does not take the medicine or have the test or procedure.
  • If your child has a follow-up appointment, write down the date, time, and purpose for that visit.
  • Know how you can contact your child’s provider after office hours. This is important if your child becomes ill and you have questions or need advice.
Online Source: Cytomegalovirus, Centers for Disease Control and Preventionhttp://www.cdc.gov/cmv/overview.html
Online Source: Infectious Mononucleosis, Centers for Disease Control and Preventionhttp://www.cdc.gov/epstein-barr/about-mono.html
Online Source: Epstein Barr Virus and Infectious Mononucleosis Lab Testing, Centers for Disease Control and Preventionhttp://www.cdc.gov/epstein-barr/laboratory-testing.html
Online Source: Mononucleosis, American Academy of Pediatricshttps://www.healthychildren.org/English/health-issues/conditions/infections/Pages/Mononucleosis.aspx
Author: Wheeler, Brooke
Online Editor: Metzger, Geri K
Online Editor: Sinovic, Dianna
Online Medical Reviewer: Freeborn, Donna, PhD, CNM, FNP
Online Medical Reviewer: Lentnek, Arnold, MD
Online Medical Reviewer: Sather, Rita, RN
Date Last Reviewed: 11/1/2016
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