Mononucleosis (also called mono) is a contagious viral infection. Most infants and children exposed to the virus get only mild flu-like symptoms or no symptoms at all. However, infection is usually more serious in teens and young adults. While the virus is active it causes symptoms and can spread to others. After symptoms subside, the virus stays in the body and eventually becomes inactive. Once you have one case of mono, you are unlikely to develop symptoms again.

The virus is  usually  spread by contact with saliva, often by kissing.  It may also spread by breastmilk, blood, or sexual contact.  It takes about 4 to 6 weeks to develop symptoms after exposure.

Early symptoms include headache, nausea, tiredness and general muscle aching. This is followed by sore throat and fever. Lymph glands in the neck, under the arms, or in the groin may be swollen. Symptoms usually go away in about 1 to 2 months. But they can last up to four months.

If symptoms have been present less than 1 week or more than 3 weeks, the blood  test used to diagnose this disease may be negative even though you have the illness.  In this case, other tests may be done.

Taking the antibiotics ampicillin or amoxicillin during a mono infection may cause a skin rash . This is not serious and will fade in about one week. The cause is a reaction of the drug with the virus.

Mono can cause your spleen to swell. The spleen is a fist-sized organ in the upper left abdomen that stores red blood cells. Injury to a swollen spleen can cause the spleen to rupture. This can cause life-threatening internal bleeding. To avoid this, do not play contact sports or perform strenuous activity for 8 weeks, or until cleared by your healthcare provider. A sharp blow could rupture a swollen spleen

Home care

  • Rest in bed until the fever and weakness have gone away.

  • Drink plenty of fluids, but avoid alcohol. Otherwise, you may eat a regular diet.

  • Ask your healthcare provider about using over-the-counter medicines to treat symptoms such as fever, pain, or an itchy rash.

  • Over-the-counter throat lozenges may help soothe a sore throat. Gargling with warm salt water (1/2 teaspoon in 1 glass of warm water) may also be soothing to the throat.

  • You may return to work or school after the fever goes away and you are feeling better. Continue to follow any activity restrictions you have been given.

Preventing spread of the virus

To limit the spread of the virus, avoid exposing others to your saliva for at least 6 months after your illness (no kissing or sharing utensils, drinking glasses, or toothbrushes).

Follow-up care

Follow up with your healthcare provider within 1 to 2 weeks or as advised by our staff to be sure that there are no complications. If symptoms of extreme fatigue and swollen glands last longer than 6 months, see your healthcare provider for further testing.

When to seek medical advice

Call your healthcare provider right away if any of the following occur:

  • Excessive coughing

  • Yellow skin or eyes

  • Trouble swallowing

Call 911

Call 911 if any of the following occur:

  • Severe or worsening abdominal pain

  • Trouble breathing