Mononucleosis (mono)

Overview

Mono (infectious mononucleosis) is an infection that is most common in teens and young adults. It is often called the kissing disease because it spreads through saliva.

Most people get the Epstein-Barr virus at some point. Young children often have no symptoms. Teens and adults are more likely to get sick with mono. Mono can make the spleen swell, so contact sports must wait until you recover.

Symptoms

Symptoms often start slowly and may not all happen at once.

• Extreme fatigue
• Fever
• Sore throat that gets worse over days
• Swollen glands in the neck and armpits
• Headache and body aches

Less common

• Swollen tonsils with white patches
• Rash
• Pain under the left ribs from a swollen spleen
• Yellow skin or eyes
• Loss of appetite

How it usually goes

• 4 to 6 weeks after contact: Symptoms start slowly.
• About 10 days: Fever usually goes away.
• 2 to 4 weeks: Most symptoms are gone. Swollen glands and spleen heal.
• Weeks to months: Tiredness may linger.

Look up a symptom: Fatigue · Feeling weak all over · Fever · Sore throat · Swollen glands · Upper left belly pain (under the left ribs) · White patches or swollen tonsils

When to get medical care

Causes

Mono is most often caused by the Epstein-Barr virus (EBV), a herpes-family virus. Other viruses can cause a similar illness.

EBV spreads through saliva by kissing or sharing drinks, food, and personal items. It can stay in saliva for a long time after you feel better.

Does it spread or run in families?

• Yes, it can spread from person to person.
• How it spreads: saliva.
• Washing hands often and staying home when sick help protect others.

Who is more likely to get it

• Being a teen or young adult
• Close contact with someone who has mono
• Living in close quarters, like dorms

Possible complications

• Enlarged spleen: Can tear with a hit to the belly
• Liver inflammation: Can cause yellow skin or eyes
• Dehydration: From a throat too sore to drink

Diagnosis

A healthcare professional can often tell from your symptoms and an exam.

Questions you may be asked

• How long you've felt tired and sick
• Sore throat, fever, and swollen glands
• Belly pain, especially under the left ribs
• Whether you've been near someone with mono

The exam

They'll check your throat, the glands in your neck and armpits, and gently feel your belly for a swollen spleen or liver.

Tests

Tests may be done if the signs aren't typical:

• Mono blood test: A quick test looks for antibodies to the virus. It may be negative early on.
• Blood count: Mono often causes more white blood cells, some of them unusual looking.
• Strep test: To check for strep throat, which can look like mono.

Treatment

There is no cure for mono. Antibiotics and antiviral medicines don't help. Treatment eases symptoms while your body fights the virus.

Self-care

• Get lots of rest
• Drink plenty of fluids
• Gargle with warm salt water to ease a sore throat
• Avoid contact sports and heavy lifting until your healthcare professional says it's safe, often about a month
• Don't share drinks, utensils, or kisses while sick

Medicines

Over-the-counter medicines ease pain and fever.

Ask before taking acetaminophen if your liver is swollen or you have yellow skin or eyes.

If your throat or tonsils swell so much it's hard to swallow or breathe, your healthcare professional may prescribe steroid medicine.

How it compares

Prevention

There is no vaccine for mono. To lower the risk:

• Don't kiss or share drinks, food, or utensils with someone who has mono
• Wash your hands often
• Don't share toothbrushes or lip balm

Which doctor treats this

• Start with your primary care provider (family doctor or internist).
• They may send you to an infectious disease specialist, for hard-to-treat infections.

Back to school, work, or sports

• Go back to school or work when you feel well enough.
• Avoid contact sports and heavy lifting for at least 3 to 4 weeks because the spleen can burst.

Children, pregnancy, and older adults

• Children: Young children often have mild symptoms or none at all.
• Athletes: No contact sports or hard training until cleared, often about a month, to protect the spleen.
• Adults over 35: More likely to have liver problems like yellow skin or eyes.

Pregnancy and breastfeeding

• If you're pregnant or planning to be, tell your prenatal provider about this condition.
• Some infections can pass to the baby during pregnancy or birth. Tell your provider if you've been exposed.
• Don't start or stop any medicine on your own. Some are safe in pregnancy and some need to be changed.
• Ask before taking any pain reliever. The FDA advises avoiding ibuprofen and naproxen after 20 weeks unless your doctor says to.
• Breastfeeding: Most medicines are fine, but ask. The NIH LactMed database lists what's known about each one.

Outlook

Nearly everyone recovers fully. Most feel better in 2 to 4 weeks, though tiredness can last for weeks or even months.

Getting ready for your visit

Mention any sports you play.

What to bring

• When symptoms started
• A list of medicines, including any antibiotics
• Your sports or work activities

Questions to ask

• When can I go back to sports?
• When can I go back to school or work?
• How do I keep from spreading it?
• What signs mean I should come back?

Research studies

Research studies test new ways to find and treat health problems. Some are looking for volunteers. Talk with your doctor before joining one.

Search ClinicalTrials.gov for studies on Mononucleosis (mono)