What Is Mononucleosis?
Mononucleosis (mono) is a viral infection that causes a sore throat and fever. Cases often happen in teens and young adults. It goes away on its own after a few weeks of rest.
What Causes Mono?
Mononucleosis (mah-no-noo-klee-OH-sus), or infectious mononucleosis, usually is caused by the Epstein-Barr virus (EBV). Most kids are exposed to EBV at some point while growing up. Infants and young kids infected with EBV usually have very mild symptoms or none at all. But infected teens and young adults often develop the symptoms that define mono.
Other viruses, such as cytomegalovirus, can sometimes cause a mono-like illness too.
What Are the Signs & Symptoms of Mononucleosis?
Signs of mono usually show up about 1–2 months after someone is infected with the virus. Its most common symptoms are sometimes mistaken for strep throat or the flu. These include:
- sore throat with swollen tonsils that may have white patches
- swollen lymph nodes (glands) in the neck
- being very tired
A person also can have:
- sore muscles
- belly pain with a larger-than-normal liver or spleen (an organ in the upper left part of the belly)
- skin rash
- loss of appetite
How Is Mono Treated?
The best treatment for mono is plenty of rest and fluids, especially early in the illness when symptoms are most severe. There is no specific medicine for mono, but acetaminophen or ibuprofen can help to relieve fever and aching muscles. Antibiotics will not help, because they’re only effective against bacteria. Someone with mono who takes an antibiotic may end up getting a rash.
Never give aspirin to a child who has a viral illness because its use has been linked to Reye syndrome, which may cause liver failure or even be fatal.