Infectious Mononucleosis

An infection causing swollen lymph nodes and a sore throat that is common in adolescence and early adulthood

  • Most common between the ages of 12 and 20
  • Gender, genetics, and lifestyle are not significant factors

Infectious mononucleosis is known as the “kissing disease” of adolescence and early adulthood because it is mainly transmitted in saliva. Another name is glandular fever because the symptoms include swollen lymph nodes (glands) and a high temperature. The illness is usually characterized by tonsillitis (see Pharyngitis and tonsillitis), which may be severe.

What is the cause?

Infectious mononucleosis is caused by the Epstein–Barr virus (EBV), which attacks lymphocytes, the white blood cells that are responsible for fighting infection. EBV infection is very common; about 9 in 10 people have been infected by the age of 50. More than half of all infected people do not develop symptoms and, consequently, are unaware that they have been infected.

What are the symptoms?

If symptoms of infectious mononucleosis develop, they usually do so 4–8 weeks after infection and appear over several days. Symptoms may include:

  • High fever and sweating.

  • Extremely sore throat, causing difficulty in swallowing.

  • Swollen tonsils, often covered with a thick, greyish-white coating.

  • Enlarged, tender lymph nodes in the neck, armpits, and groin.

  • Tender abdomen as the result of an enlarged spleen.

These symptoms are often accompanied by poor appetite, weight loss, headache, and tiredness; sometimes, there may be a rash on the trunk and face. In some people, the sore throat and fever clear up quickly, and the other symptoms last less than a month. Other people may be ill for longer and feel lethargic for months after the infection.

What might be done?

Your doctor will probably diagnose the infection from your enlarged lymph nodes, sore throat, and fever. A blood test may be carried out to look for antibodies against EBV. A throat swab may also be taken to exclude bacterial infection, which may need to be treated with antibiotics.

There is no specific treatment for infectious mononucleosis, but simple measures may help to relieve symptoms. Drinking plenty of cool fluids and taking over-the-counter painkillers, such as paracetamol, may help to control the fever and pain. Alcohol should be avoided until you have recovered fully, because the liver may be affected. Contact sports should also be avoided until at least 6–8 weeks after recovery, because the spleen may be enlarged as a result of the illness

Swollen tonsils

In infectious mononucleosis, the tonsils become swollen, causing a very sore throat. They may also become covered with a thick, greyish-white coating.

What is the prognosis?

Almost everyone who has infectious mononucleosis makes a full recovery eventually. However, in some people, recovery may be slow, and tiredness may last for weeks or even months after the symptoms first appear. One attack of the disease, with or without symptoms, provides lifelong protection.

From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.

The subjects, conditions and treatments covered in this encyclopaedia are for information only and may not be covered by your insurance product should you make a claim.

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