Infectious mononucleosis (mono), sometimes called glandular fever, is a viral infection most often caused by the Epstein-Barr virus (EBV). It commonly affects teens and young adults, especially college students, but anyone can get it.
Mono can cause symptoms such as extreme fatigue, sore throat, fever and swollen lymph nodes. Symptoms may last several weeks and sometimes several months.
Mono is usually not life-threatening, but it can make you feel very sick and disrupt daily life. In some cases, complications can occur, including swelling of the liver or spleen. An enlarged spleen may increase the risk of rupture, which is a medical emergency. People with weakened immune systems may have a higher risk of complications.
Most cases of mononucleosis are caused by the Epstein-Barr virus (EBV)What is epstein barr virus, a common virus in the herpes virus family.
EBV spreads mainly through saliva and close contact, which is why mono is often called the “kissing disease.” The virus multiplies in the nose and throat and spreads easily between people.
Many people are exposed to EBV during childhood and have mild or no symptoms. But if someone first becomes infected during the teen or young adult years, they are more likely to develop infectious mononucleosis.
After infection, EBV stays in the body in a dormant state for life. The virus can occasionally reactivate without causing symptoms. This means someone may sometimes spread the virus even if they feel healthy.
Mono symptoms typically appear four to six weeks after infection and may last several weeks.
Common symptoms include:
Less common symptoms may include:
Fatigue and sore throat are often worst during the first two to four weeks. Some people recover within a few weeks, while others may feel tired for several months.
Mono spreads mainly through saliva and close contact. It is most common among teens and young adults in schools, colleges and social settings.
You can get mono through:
If you have mono, you can help prevent spreading the virus by:
Most people recover from mono without serious problems, but complications can occur.
Possible complications include:
Mono can cause the spleen to enlarge. Although rare, this increases the risk of a ruptured spleen, which is a medical emergency.
Mono may cause temporary liver inflammation, which can lead to symptoms such as abdominal pain or jaundice.
Mono can sometimes lower red blood cell levels.
Low platelet counts may affect blood clotting.
Inflammation of the heart muscle.
Rare complications include meningitis, encephalitis or Guillain-Barré syndrome.
Swelling may occasionally block breathing.
People with weakened immune systems due to HIV/AIDS, organ transplant, cancer treatment or immunosuppressive medications may have a higher risk of complications.
Several illnesses can cause symptoms that look similar to mononucleosis.
Both strep throat and mono can cause severe sore throat, fever and swollen lymph nodes. Strep throat is caused by bacteria (group A Streptococcus), not EBV.
The flu can cause fever, fatigue and body aches similar to mono. Flu symptoms usually start suddenly and often include more respiratory symptoms.
Early COVID-19 symptoms can include fatigue, fever and sore throat, which may resemble mono.
CMV can cause a mono-like illness with fatigue and fever but is caused by a different virus.
A health care provider can help determine the cause of your symptoms.
If symptoms last more than about 10 days, a health care provider may evaluate you for mono.
Diagnosis may include:
Your provider may check for fever, swollen lymph nodes, enlarged tonsils or an enlarged spleen.
Blood tests can detect antibodies to the Epstein-Barr virus. Providers may also order tests such as:
These tests help confirm the diagnosis and rule out other illnesses with similar symptoms.
Contact a health care provider if you have symptoms that worsen or do not improve, especially if you experience:
Call 911 or go to the emergency room if you experience:
These symptoms may indicate serious complications.
There is no specific cure or vaccine for mono. Treatment focuses on relieving symptoms while your immune system fights the infection.
Treatment may include:
Avoid aspirin, especially in children and teens, because it is linked to Reye syndrome during viral illnesses.
In some cases, providers may prescribe corticosteroids to reduce severe swelling in the throat or tonsils.
Antiviral medications do not treat mono. Antibiotics also do not treat mono but may be prescribed if you develop another bacterial infection. Certain antibiotics such as ampicillin or amoxicillin can cause a rash in people with mono and are usually avoided.
Because mono can enlarge the spleen, avoid contact sports, heavy lifting and strenuous exercise for three to four weeks or until your provider confirms your spleen has returned to normal size. Injury to an enlarged spleen can cause rupture, which requires emergency treatment.
Many people begin to feel better within a few weeks, though fatigue can last for several months.
Recovery times vary depending on your overall health and how severe the infection is. Getting enough rest, staying hydrated, eating nutritious foods and avoiding alcohol can help support recovery.
Most people recover from mono with rest and self-care. However, medical evaluation is important if symptoms worsen or complications develop.
If you think you may have mono or symptoms that are not improving, a Banner Health provider can help. Our team can diagnose mononucleosis, monitor for complications and guide you through recovery so you can safely return to your normal activities.
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