Mononucleosis

Mononucleosis

Mononucleosis: symptoms, treatment and prevention


Symptoms of mononucleosis

  • Extreme fatigue
  • Sore throat
  • Stuffy, runny nose
  • Swollen eyelids
  • Small, red bumps on the skin
  • Swollen and sensitive lymph nodes on the sides and back of the neck
  • High fever, sometimes reaching 40.5°C (104.9°F) late in the day
  • Headaches or muscle aches
  • Lack of appetite

Consult your doctor if symptoms do not improve after 3 or 4 days, especially if your child has a high fever.

Seek emergency medical help (9-1-1) if your child:

  • Has sharp pain on the upper left side of the abdomen
  • Has difficulty breathing due to an extremely sore throat
  • Has severe headaches combined with vomiting
  • Can’t manage to eat or drink

What is mononucleosis?

Mononucleosis is an illness normally caused by the Epstein-Barr virus, a member of the herpes family of viruses.

The mononucleosis virus is contagious, but not as contagious as the viruses causing the common cold or the flu. It is often transmitted by direct contact with the saliva of an infected person. That’s why mononucleosis is nicknamed the “kissing disease.”

Because mononucleosis doesn’t usually cause much coughing or sneezing, it’s rarely transmitted by airborne droplets. However, you can catch the disease by sharing utensils, glasses, etc.

Once infected with the Epstein-Barr virus, people are then immune to the illness for life. Half of 5-year-old children are believed to have already been exposed to the virus without necessarily developing mononucleosis. Around 90% of adults aged 40 are thought to be immune to the disease.

Potential complications

Mononucleosis is a relatively harmless illness that usually resolves on its own.

It can, however, cause the spleen to swell, making it more fragile. In rare cases, the spleen may rupture. For this reason, children with mononucleosis should not engage in strenuous sports or heavy physical exertion (e.g., heavy lifting) for 3 to 4 weeks.

Other, rarer complications can occur with mononucleosis, such as difficulty breathing, severe headaches with vomiting, a significant decrease in urine output, or jaundice. It’s a good idea to speak to a doctor if new symptoms arise, or if your child seems to be getting worse instead of better.

Age: Teenagers and young adults are particularly affected. The mononucleosis virus can affect young children, but causes a mild upper respiratory tract infection. Since children do not show the classic symptoms of mononucleosis, infection with this virus often goes undetected until adolescence.
Duration: Primary symptoms resolve within 2 to 3 weeks, but the fatigue may last several months.
Infectious period: Mononucleosis is contagious from the incubation period, which takes place 4 to 6 weeks before symptoms begin, until a few months after recovery. A study has confirmed that the virus may continue to be present in secretions at the back of the throat up to 6 months after the start of the infection.
How it spreads: Mononucleosis spreads through direct or indirect contact (e.g., contaminated utensils, sharing glasses or water bottles) with the saliva of an infected person and, more rarely, in the event of a blood transfusion.
Incubation period: 4 to 6 weeks. The incubation period is shorter in young children. They will be infected with the Epstein-Barr virus, but will often show few or no symptoms.
Isolation period: An isolation period may not be necessary or useful. However, your child will need plenty of rest, and they’ll have to refrain from physically demanding activities for at least 3 to 4 weeks. To reduce the risk of a ruptured spleen, your child should return to physical activity gradually, engaging at first in only light activities involving no physical contact with other children.
Vaccine: There is no vaccine for Epstein-Barr virus.

What to do at home

  • Allow your child to rest. Based on the doctor’s recommendations, they will probably have to miss school.
  • To relieve pain and fever, give your child acetaminophen (Tylenol®, Tempra®) or ibuprofen (Advil®, Motrin®). Never give acetylsalicylic acid (ASA), such as Aspirin®, to a child or teenager.
  • Offer them frequent cool drinks, such as water or certain juices (e.g., pear, apple, grape). Avoid carbonated beverages and citrus juices such as orange, lemon, and grapefruit, which can irritate a sore throat.
  • Have your child to gargle a few times a day with 2.5 ml (1/2 tsp.) of salt dissolved in a glass of warm water.
  • Give them sugar-free hard candies and lozenges containing honey, herbs, or pectin to soothe their sore throat.
  • Limit their screen time and suggest other enjoyable activities such as drawing, modelling clay, crafts, simple board games, or reading stories.
  • Ensure that your child avoids heavy physical exertion and any kind of strenuous activity or contact sport for at least 3 to 4 weeks.

Treatment

Mononucleosis is a viral infection. That means antibiotics won’t help, unless the virus is complicated by a bacterial infection such as strep throat, sinusitis, or tonsilitis.

If your child has to take antibiotics, make sure they take the medication for the full prescribed period, even if they feel better after a few days. A full course of treatment reduces the risk of bacterial resistance to the prescribed antibiotic.

The doctor will avoid prescribing penicillin if possible, since it causes significant skin reactions in 90% of mononucleosis patients. These tend to resemble allergic reactions, although they are not.

If necessary, the doctor may prescribe corticosteroids, for complications such as severe upper airway obstruction with difficulty breathing, which may occur if tonsils become too swollen. This complication arises in fewer than 3.5% of cases.

Prevention

You can’t prevent an Epstein-Barr virus infection, but you can tell your sick child how to avoid contaminating others.

Here’s how your child can protect those around them:

  • Do not share utensils, glasses, or dishes with others.
  • Don’t share food.
  • Wash hands thoroughly.
  • Sneeze into a tissue or the crook of the elbow.

 

Naître et grandir

Scientific review: Dr. Anne-Claude Bernard-Bonnin, pediatrician
Research and copywriting:The Naître et grandir team
Updated: April 2023

 

Photo: GettyImages/Elena Medoks

 

Resources and references

Note: The links to other websites are not updated regularly, and some URLs may have changed since publication. If a link is no longer valid, please use search engines to find the relevant information.

  • Aronson, Mark D., and Paul G. Auerwaerter. “Infectious mononucleosis.” UpToDate. 2021. uptodate.com
  • Centers for Disease Control and Prevention. “About infectious mononucleosis.” CDC. 2020. cdc.gov
  • Fugl, Anders, and Christen L. Andersen. “Epstein-Barr virus and its association with disease – a review of relevance to general practice.” BMC Family Practice, vol. 20, no. 1, 2019, p. 62. pubmed.ncbi.nlm.nih.gov
  • Gaucher, N., and C. Renaud. “Mononucléose infectieuse.” In Dictionnaire de Pédiatrie Weber, third edition, edited by Turgeon, Jean, et al. Chenelière Éducation, 2014, pp. 804–807.
  • Nemours KidsHealth. “Mononucleosis (Mono).” KidsHealth. 2020. kidshealth.org
  • Mayo Clinic Staff. “Mononucleosis.” Mayo Clinic. 2022. mayoclinic.org
  • Ministère de la santé et des services sociaux. Mononucléose infectieuse. 2016. publications.msss.gouv.qc.ca
  • Sylvester, Jillian E., et al. “Infectious mononucleosis: rapid evidence review.” American Family Physician, vol. 107, no. 1, 2023, pp. 71–78. aafp.org

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