What is infectious mononucleosis?

Infectious mononucleosis (also called mono) is a viral infection. It is a common infection, but often causes mild symptoms or none at all in younger children. For teens and young adults, it is a frequent cause of illness and missed school.

What is the cause?

The virus that usually causes mono is called the Epstein-Barr virus (EBV). It is spread mainly through saliva, which is why it has the nickname “kissing disease.” Coughing, sneezing, or sharing drinking or eating utensils can also spread the virus.

What are the symptoms?

After the virus enters the body it can take 4 to 6 weeks before symptoms begin. The first symptoms usually are:

• Feeling very tired (you may sleep 12 to 16 hours per day)
• Fever
• Headache
• Muscle aches

After a few days of tiredness, fever, and aches, other symptoms are:

• Sore throat
• Swollen tonsils with a yellowish white coating
• Swollen glands (lymph nodes) in the neck

You may also have:

• A loss of appetite
• Nausea
• Achy joints
• A fine, red rash, often on the chest, sometimes including tiny red spots in the mouth

Mono is most infectious from right before you start having symptoms until several days after your fever is gone. The Epstein-Barr virus stays in your body after you recover. You could have mono again, but this is unusual.

How is it diagnosed?

Your healthcare provider will ask about your symptoms and medical history and examine you. You will have blood tests. You may also have a throat swab to check for strep throat.

How is it treated?

There is no specific drug treatment for mono. Treatment can help to decrease your symptoms. Because it is a viral illness, antibiotics are not helpful.

The most important thing you can do is to get plenty of rest. Usually the fever, sore throat, and extreme tiredness last about 1 to 2 weeks. However, the tiredness can last for weeks or months. As you recover, you will be able to slowly go back to your normal activities.

It is very important that you drink lots of liquid to avoid becoming dehydrated. One way to tell if you are drinking enough liquid is to look at the color of your urine. It should be very light yellow. Do not drink alcohol when you have mono.

You could also develop strep throat or a sinus infection while you have mono. These infections may be treated with antibiotics.

Sometimes the mono infection causes the tonsils to become so big that they nearly block your throat. If this happens, your provider may prescribe a steroid medicine to help shrink them.

Rarely, mono can cause your spleen to get very swollen. The spleen is an organ in the left upper part of your belly that helps your body fight infection. The spleen can get so swollen that it actually bursts (ruptures). This is most likely to happen if you get hit in the belly or put pressure on your belly. A rupture of the spleen causes severe bleeding and can be life-threatening. You will need emergency care if this happens.

How can I take care of myself?

Follow the full course of treatment prescribed by your healthcare provider. In addition:

• Get lots of rest.
• Take nonprescription pain medicine, such as acetaminophen, ibuprofen, or naproxen. Read the label and take as directed. Unless recommended by your healthcare provider, you should not take these medicines for more than 10 days.
  • Nonsteroidal anti-inflammatory medicines (NSAIDs), such as ibuprofen, naproxen, and aspirin, may cause stomach bleeding and other problems. These risks increase with age.
  • Acetaminophen may cause liver damage or other problems. Unless recommended by your provider, don’t take more than 3000 milligrams (mg) in 24 hours. To make sure you don’t take too much, check other medicines you take to see if they also contain acetaminophen. Ask your provider if you need to avoid drinking alcohol while taking this medicine.
• Avoid heavy lifting and any kind of jarring activity or contact sport, to prevent injury to your spleen. Check with your healthcare provider about how long you should avoid these activities.

Ask your provider:

• How and when you will hear your test results
• How long it will take to recover
• If there are activities you should avoid and when you can return to your normal activities
• How to take care of yourself at home
• What symptoms or problems you should watch for and what to do if you have them

Make sure you know when you should come back for a checkup. Keep all appointments for provider visits or tests.

How can I help prevent mononucleosis?

• Wash your hands often and especially after using the restroom, coughing, sneezing, or blowing your nose. Also wash your hands before eating or touching your eyes.
• In general, don’t share food, eating utensils, or drink containers with anyone.
• Avoid kissing anyone who has mono until it has been several days since their fever went away. The virus is less contagious at this time.