What is mononucleosis?

Mononucleosis (often called "mono") is an infection caused by the Epstein-Barr virus.


What are the symptoms of mono?

Symptoms of mono include:

  • Fever
  • Sore throat
  • Fatigue
  • Weakness
  • Swollen glands in your neck and armpits
  • Loss of appetite
  • Night sweats

Symptoms in young children are generally mild, while symptoms in adolescents and young adults tend to be more severe.

Causes & Risk Factors

How do people get mono?

Mono is not spread as easily as some other viruses, such as the common cold. The mono virus is found in saliva and mucus. It is usually passed from one person to another through kissing, which is why it is often called the kissing disease. However, mono can also be passed through exposure to a cough, sneeze or through sharing food utensils (such as drinking glasses, spoons and forks) with someone who has mono. Signs of mono usually develop 4 to 6 weeks after you're exposed to the virus. Generally, people only get mono once. It's most common among people 15 to 35 years of age.

Diagnosis & Tests

How is mono diagnosed?

Your doctor will probably first ask you some questions about your symptoms and then may do blood tests to confirm the diagnosis. One common test used to diagnose mono is called the Monospot test. Sometimes other blood tests are needed if the results of the Monospot test aren't clear.


Can mono be cured?

No, there isn't a cure for mono. But the virus will go away on its own. Symptoms usually last about 4 weeks.

How is mono treated?

The main goal of treatment is to relieve your symptoms. The following list includes tips on treatment:

  • Rest. Sleep helps your body fight infection.
  • Drink plenty of fluids. They help prevent dehydration.
  • If you have a sore throat, gargle with salt water or suck on throat lozenges, hard candy or flavored frozen desserts (such as Popsicles).
  • You may want to take acetaminophen (one brand name: Tylenol) or ibuprofen (some brand names: Advil, Motrin, Nuprin) to relieve pain and fever. Do not give aspirin to children. Aspirin should be avoided because it has been associated with a disease called Reye's syndrome in children. Reye's syndrome is a serious illness that can lead to death.

Do I need an antibiotic?

Antibiotics are not effective against mono. Mono is caused by a virus and antibiotics don't work against viruses. If you have a bacterial infection in addition to having mono (such as strep throat), your doctor may give you an antibiotic to treat that infection.

What about sports and exercise?

Avoid sports, physical activities or exercise of any kind until your doctor tells you it's safe. Moving around too much puts you at risk of rupturing your spleen, especially if it is enlarged. You need to avoid physical activities and contact sports for about 3 to 4 weeks after you've had mono.


Does mono have any complications?

Sometimes. The main complication with mono is the enlargement of the spleen. The spleen is like a large gland. It's located in the upper part of your abdomen on the left side. It helps filter your blood. In severe cases of mono, the spleen can rupture (tear open).

Although a ruptured spleen is rare in people who have mono, it's wise to be aware of the signs and call your doctor right away if you notice any of them. Signs of a ruptured spleen include sharp pain in the left upper part of your abdomen (under the left chest), feeling lightheaded, feeling confused, blurred vision and fainting.

Questions to Ask Your Doctor

  • How did I get mononucleosis?
  • I have mononucleosis. Should my girlfriend get tested?
  • What is the best treatment for me?
  • How long will it be before I can exercise safely?
  • How long should I keep my child home from school?
  • How can I make sure that the rest of my family doesn't get mono?
  • Are there any medicines I can take to feel better?
  • How long will I be contagious?
  • If I start having pain in my side, should I call my doctor immediately?
  • If I have mono once, will I get it again?