May also be called: Mono; Kissing Disease

Mononucleosis, or "mono," is an infection usually caused by the Epstein-Barr virus (EBV), a common virus that most kids are exposed to at some point.

More to Know

Mono can develop at any age but most often occurs in teens ages 15-17 and adults in their twenties. Typical symptoms include fever, sore throat, swollen lymph nodes (in the neck, underarms, or groin), and constant fatigue or weakness. Sore muscles, enlarged liver and spleen, skin rash, and loss of appetite also may occur. Infants and young kids infected with EBV usually have very mild symptoms or none at all.

Mono is spread through contact with saliva: kissing, coughing, sneezing, or sharing straws and eating utensils. For this reason, it is also commonly called the "kissing disease."

Mono symptoms usually go away on their own within 2-4 weeks but sometimes the fatigue and weakness lasts for months. The best treatment is plenty of rest and keeping hydrated. Acetaminophen or ibuprofen can help to relieve the fever and aching muscles.

Keep in Mind

Anyone with mono symptoms should be evaluated by a doctor. Most cases of mono aren't serious, but sometimes serious complications (like a ruptured spleen) do happen. If the spleen is swollen, contact sports should be avoided until the doctor says otherwise.

All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts.