What are the symptoms of mono (Mononucleosis) in kids?

mono symptoms in kids
Medically reviewed by Dr. Mandy Liedeman


For parents and caregivers who aren’t medical pros, spotting the signs of mono in kids might seem like solving a puzzle. So, let’s break it down. When your little one feels more tired than usual, or their glands around the neck are a bit swollen, it might be mono. Mono is one of the most widespread viruses known as Epstein-Barr virus (EBV). The majority of people will get infected at some point in their lives. But this isn’t just about physical stuff. Mono can also play with a child’s feelings. Let us understand these signs simply, explore how mono shows up in kids, and learn how to support them. 

What is mono or infectious mononucleosis?

Infectious mononucleosis (IM) is marked by a triad of symptoms: fever, tonsillar pharyngitis, and lymphadenopathy. Initially termed “Drusenfieber” in 1889, it was later coined “infectious mononucleosis” in 1920 to describe a febrile illness in six college students exhibiting absolute lymphocytosis and atypical mononuclear cells in the blood. The link between Epstein-Barr virus (EBV) and IM was established when a lab worker infected with EBV developed IM along with a positive heterophile test. Environmental sources have not detected the virus, indicating that humans serve as the primary reservoir.

Teenagers and young adults, especially college students, frequently experience it. Saliva is a common way infectious mononucleosis spreads, making it highly contagious. Since many individuals with the illness do not exhibit any symptoms, prevention is frequently challenging. Infectious mononucleosis leaves the virus dormant in the pharynx and blood cells for life, whether you or your child contracted it.

What are the symptoms of mononucleosis in kids?

Mononucleosis can present with a variety of symptoms in toddlers and children. These symptoms are often similar to those seen in adolescents and adults but might manifest differently in younger individuals. Common symptoms of mononucleosis in kids include:


Persistent tiredness is a hallmark symptom of mono in children. Children with mono may feel more lethargic than usual.

Sore Throat

A sore throat, often severe, is a common early symptom. It may be accompanied by redness and swelling.


Mono can cause a high fever, which may come and go. Monitoring your child’s temperature is essential.

Swollen Glands

Enlarged lymph nodes, especially lymph nodes in the armpits, neck, and groin, are typical in mono cases.

Enlarged Tonsils

The tonsils may become more significant than usual and have a white coating.


Children with mono may experience headaches, adding to their overall discomfort.

Abdominal Pain

Some kids may develop mild abdominal pain, especially in the upper left side, due to a slightly enlarged spleen.

Fever, sore throat, abdominal pain and enlarged tonsils may all be signs of Mono in your child. Consult now

How did my child get mono?

Since mono is contagious, a person who has it can infect others with it. Despite the “kissing disease,” there are alternative ways to contract mono. The virus is highly transmissible and can propagate via the following channels:

Sharing things

Mono can transfer using straws, toothbrushes, or food from the same plate.


Coming into contact with infectious saliva is the most frequent way of transmission. This can happen when you kiss, share drinks, or use cutlery or personal things that have come into touch with the saliva of an infected individual.

Airborne droplets

When an infected individual sneezes or coughs, tiny droplets are released into the air, which can also spread the virus. A person who is not affected may contract the infection if they breathe in these droplets.


Though less common, transmission through blood can occur. This can happen through blood transfusions, organ transplants, or sharing of needles.

Bottles, lip gloss, and forks.

How to diagnose mono in a child?

Physical exam

Based on a physical examination, your symptoms, their duration, and your signs and symptoms, your doctor may suspect mononucleosis. They will search for symptoms like enlarged tonsils, liver, spleen, or lymph nodes and evaluate how these symptoms connect to the symptoms you’ve described.

Blood tests

Antibody tests

If further confirmation is required, a mono-spot test may be performed to screen your blood for Epstein-Barr virus antibodies. Results from this screening test are available in a day. However, in the first week of the sickness, it might not pick up the infection. Another antibody test can identify the illness even in the first week of symptoms, although it takes longer to get results.

White blood cell count

In order to search for abnormal-looking lymphocytes or an increased quantity of white blood cells (lymphocytes), your doctor may perform additional blood tests. The most frequent laboratory result of infectious mononucleosis (IM) is lymphocytosis, characterized by an absolute count >4500/microL or a differential count >50 percent on a peripheral smear. The smear may also detect significant atypical lymphocytosis, which is defined as more than 10% of total lymphocytes. In patients with IM, CD8+ cytotoxic T cells comprise the most reactive lymphocytes. Although these blood tests cannot confirm mononucleosis, they may raise the probability.


Most individuals have elevated aminotransferases, but these are self-limited. When a patient has pharyngitis, abnormal liver function tests strongly point to the probability of IM as a diagnosis.

Worried about managing and recognizing mono in your child? Consult now

How do you treat mono in a child?

Mononucleosis (mono) has no known cure; instead, supportive care and symptom management are the mainstays of mononucleosis treatment, which helps children recover. The following steps can be taken to reduce symptoms and encourage healing:


Encourage your child to get plenty of rest. Fatigue is a common symptom of mono, and adequate rest is essential for recovery.


Ensure your child stays well-hydrated by drinking plenty of fluids. This helps prevent dehydration, especially if they have a sore throat and difficulty swallowing.

Pain and Fever Relief

Acetaminophen and ibuprofen, two over-the-counter pain medications, can help lower fever and relieve pain. But before administering any medication to a youngster, speaking with a medical expert is crucial.

Avoidance of Strenuous Activities

Due to the risk of splenic rupture (although rare), children with mono are usually advised to avoid strenuous physical activities, contact sports, or heavy lifting until their spleen returns to its standard size.

Comfort Measures

Provide soothing measures for a sore throat, such as warm salt water gargles, throat lozenges, or popsicles.

Healthy Nutrition

Ensure your child eats a balanced, nutrient-rich diet to help their immune system recuperate.

Other treatments Include:

  • Ibuprofen or acetaminophen for fever or body aches. Aspirin should never be given since it can cause Reye’s syndrome, a dangerous condition.
  • Steroid medications to treat swollen tonsils or lymph nodes that are causing respiratory problems.
Get investigated for Mononucleosis. Consult now

How long does mono last in kids?

Usually, the symptoms of mono disappear in two to four weeks. However, fatigue and weakness can last several months for some teenagers.

Consult a doctor

The majority of kids with mono recover without any issues. Complications may arise in rare circumstances. Should any of these occur, get in touch with your child’s physician:

  • Sharp, sudden pains lasting over five minutes in the upper left abdomen (tummy). This may indicate a severe splenic issue.
  • Any difficulty swallowing, breathing, or eating
  • Decreased urination in addition to dehydration (feeling “dried out”)
  • Incredibly sleepy, agitated, or unresponsive
  • Any other symptoms that worsen or persist

FAQs about Mononucleosis(mono) symptoms in kids

Is mono serious in kids?

Mono is typically not serious in kids, with most recovering fully with rest and supportive care. However, complications such as an enlarged spleen or liver can occur.

How long is mono contagious in kids?

After the commencement of the disease, a person is contagious for an average of six months. The EB virus is a lifelong infection that occasionally causes minute sore throats in otherwise perfectly healthy individuals. It is, therefore, wise to avoid casually mingling bodily fluids at all times.

Can mono be spread by coughing?

The reason it’s called “the kissing disease” is that mono can be transmitted via kissing. It can spread through sneezing, coughing, and sharing spit-contaminated objects, including drinking glasses, straws, toothbrushes, and dining utensils. Though this is far less common, mono can also spread through blood transfusions or intercourse.

Your Doctors Online uses high-quality and trustworthy sources to ensure content accuracy and reliability. We rely on peer-reviewed studies, academic research institutions and medical associations to provide up-to-date and evidence-based information to the users.

  • Waldegrave, Charles. “Mono‐cultural, mono‐class, and so called non‐political family therapy.” Australian and New Zealand Journal of Family Therapy 6.4 (1985): 197-200.
  • Baehner, Robert L., and Stanton E. Shuler. “Infectious mononucleosis in childhood: clinical expressions, serologic findings, complications, prognosis.” Clinical Pediatrics 6.7 (1967): 393-399.
  • de Vroedt, Rania. The effect of global mobility on third culture kids: Do early childhood mobility and cultural changes contribute to poorer general mental health in adulthood?. Diss. Harvard University, 2022.
  • Retzlaff, Misty. “Infectious Mononucleosis and Your Child.” (2008).

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