Symptoms of Mono in Toddlers and Kids

Sore Throat and Swollen Glands May Be Signs

mother taking daughter's (6-7) temperature
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Since mononucleosis, or mono, is often thought of as an infection that only affects teenagers, symptoms of the so-called kissing disease in toddlers and kids may be overlooked. Clear up the myths about this medical condition with this review.

Myths About Mononucleosis

Another "myth" about mono is that an individual who contracts the infection will be sick for several months.  While you can get mono from kissing, you can also get it from other forms of close contact.

Also, although many kids do take several months to recover from mono, some are sick for just a week or two.

It really is a myth that only teens can get mono since even toddlers and preschoolers can get it. Most cases of mono do occur in older children, though.

Symptoms of Mononucleosis

Kids with mononucleosis typically have three to five days of mild symptoms such as a headache, malaise, and fatigue. The more classic symptoms of mono then follow and include:

  • a severe sore throat, with tonsils that are red, enlarged and covered in pus
  • swollen glands (lymphadenopathy) in the neck
  • fever, which can be as high as 104 F to 105 F and may last one to two weeks
  • continued malaise and fatigue, which can be extreme
  • an enlarged spleen (splenomegaly), although this doesn't occur until your child has been sick for two or three weeks
  • nausea
  • abdominal pain
  • muscle aches (myalgias)

Other signs and symptoms of mono can include hepatitis, jaundice, and a rash.

Children with mono who are treated with an antibiotic, such as ampicillin, amoxicillin or other penicillin-type antibiotics, often get a bad rash also.

Unlike many other infections, with mono, the older you are the more severe the symptoms typically are. So while a toddler or preschooler with mono might have mild symptoms and be sick for only a few days, a teenager might have a full-blown case with a severe sore throat, high fever for two weeks, and fatigue for several months.

Diagnosis of Mononucleosis

While many pediatric conditions are diagnosed clinically or by the pattern of symptoms, it's hard to do that for mono, since it has basic 'viral' symptoms. On the other hand, most younger kids with mono get better so quickly that it isn't that important to know that they even have it.

In fact, pediatricians sometimes find that when they test someone with suspected mono, the child already had it and no one even suspected it before. If your pediatrician does suspect mono, testing will likely be done, which might include:

  • A complete blood count, which may show an atypical lymphocytosis.
  • A heterophil antibody test (monospot) - may be negative if done too early in the course of your child's illness.
  • Epstein-Barr virus (EBV) titers, which can help tell if your child has a current or past EBV infection.

Since a sore throat, fever, and swollen glands are also strep throat symptoms, your child will likely also have a strep throat test.

Since five to 10 percent of cases of mono are not caused by EBV, the monospot, and EBV titers might be negative in your child with mono, although the complete blood count and symptoms might still be suggestive of a mono infection.

Mononucleosis Treatments

Unfortunately, there is no specific treatment for mono.

Since it is caused by a virus, antibiotics obviously won't work to fight a mono infection, so the treatments for mono are largely supportive.

Those treatments include bed rest, fever control, pain control for a sore throat, and fluids to prevent dehydration. Although sometimes used to treat mono, most experts recommend that steroids should only be used if a child's tonsils are so enlarged that they are truly causing an obstruction, which is not common.

What You Need To Know About Mononucleosis

Mononucleosis is usually caused by the Epstein-Barr virus (EBV) and is mainly spread by saliva. Many viruses can cause a mono-like illness, including CMV, adenovirus, Toxoplasma gondii, HIV, rubella, hepatitis A and human herpesvirus-6.

The incubation period for mono is about four to six weeks, which means that your child might not develop symptoms of mono until a month after being exposed to someone else with mono. 

Because of the risk of a ruptured spleen, a rare complication of mono, especially from contact sports, kids with mono should avoid strenuous activity until their spleen has returned to a normal size. Many experts recommend a minimum time out of sports of three to four weeks and some recommend an ultrasound to make sure the spleen has indeed returned to a normal size, especially if your child is in a sport like weightlifting, a strenuous sport, or contact sport.

Some kids have atypical or unusual cases of mono, such as just having an enlarged gland and no sore throat or fever. They may also just have a sore throat or a fever. When your child has one or more of these symptoms that just don't go away, mono could be to blame.

Children may sometimes remain fatigued for a few months or years after having mono. Since a sore throat caused by mono can be severe, your pediatrician might consider prescribing something to help with pain control if it is necessary, such as a mixture of Benadryl, Maalox, and Viscous Lidocaine that your child can use to gargle.​

Children with mono can possibly remain contagious for several weeks or months after they recover but can usually return to school once they are fever free and feel up to it.


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