Glandular fever

Glandular fever is a type of viral infection that mostly affects young adults.

It is also known as infectious mononucleosis, or "mono".

Common symptoms include:

  • a high temperature (fever)
  • a severely sore throat
  • swollen glands in the neck
  • fatigue (extreme tiredness)

While the symptoms of glandular fever can be very unpleasant, most of them should pass within two or three weeks. Fatigue, however, can occassionally last several months.

Read more about the symptoms of glandular fever.

When to seek medical advice

You should contact your GP if you suspect that you or your child has glandular fever.

While there is little your GP can do in terms of treatment, they can provide advice and support to help you control your symptoms and reduce the risk of passing the infection on to others.

You should go to your local accident and emergency (A&E) department or dial 999 for an ambulance if you have glandular fever and you:

  • develop a rasping breath (stridor) or have any breathing difficulties
  • find swallowing fluids difficult
  • develop intense abdominal pain

These symptoms can be a sign of a complication of glandular fever that may need to be treated in hospital.

What causes glandular fever?

Glandular fever is caused by the Epstein-Barr virus (EBV). The virus is found in the saliva of infected people and can be spread through:

  • kissing (it is often referred to as the "kissing disease")
  • exposure to coughs and sneezes
  • sharing eating and drinking utensils, such as cups, glasses and unwashed forks and spoons

EBV may be found in the saliva of someone who has had glandular fever for several months after their symptoms pass, and some people may continue to have the virus in their saliva on and off for years.

If you have EBV, it's a good idea to take steps to avoid infecting others while you are ill, such as not kissing other people, but there's no need to avoid all contact with others as the chances of passing on the infection are generally low.

Who is affected?

Glandular fever can affect people of all ages, but most cases affect teenagers and young adults.

Most EBV infections are thought to occur during childhood and cause only mild symptoms, or no symptoms at all.

However, if a person develops an EBV infection during early adulthood, they can develop glandular fever.

Once you have had glandular fever, it is unlikely you will develop it again. This is because people develop lifelong immunity after the initial infection.

How glandular fever is diagnosed

To diagnose glandular fever, your GP will first ask about your symptoms before carrying out a physical examination. They will look for characteristic signs of glandular fever, such as swollen glands, tonsils, liver and spleen.

Your GP may also recommend a blood test to help confirm the diagnosis and rule out infections that can cause similar symptoms, such as cytomegalovirus (CMV), rubella, mumps and toxoplasmosis.

How glandular fever is treated

There is no cure for glandular fever, but there are a number of simple treatments and measures that can help reduce the symptoms while you wait for your body to control the infection.

These include:

  • drinking plenty of fluids
  • taking over-the-counter painkillers, such as paracetamol or ibuprofen
  • getting plenty of rest and gradually increasing your activity as your energy levels improve

Occassionally, antibiotics or corticosteroids may be used if you develop complications of glandular fever.

Some people with particularly severe symptoms may need to be looked after in hospital for a few days.

Possible complications

Complications associated with glandular fever are uncommon, but when they occur they can be serious. They can include:

  • further infections of other areas of the body, including the brain, liver and lungs
  • severe anaemia (a lack of oxygen-carrying red blood cells)
  • breathing difficulties as a result of the tonsils becoming massively swollen
  • ruptured (burst) spleen, which may need to be treated with surgery


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Symptoms of glandular fever take around one to two months to develop after infection with the Epstein-Barr virus.

Main symptoms

The most common symptoms of glandular fever are:

  • a high temperature (fever)
  • sore throat – usually more painful than any previous throat infection you may have had
  • swollen glands (nodes) in your neck and possibly in other parts of your body, such as under your armpits
  • fatigue (extreme tiredness)

Other symptoms

In addition to throat pain, you may also have:

  • a general sense of feeling unwell
  • aching muscles
  • chills
  • sweats
  • loss of appetite
  • pain around or behind your eyes
  • swollen tonsils and adenoids (small lumps of tissue at the back of the nose), which may affect your breathing
  • the inside of your throat may be very red and ooze fluid
  • small red or purple spots on the roof of your mouth
  • a rash
  • swelling or "puffiness" around the eyes
  • a tender or swollen tummy
  • jaundice (yellowing of the skin and whites of the eyes)

Some of these symptoms may develop a few days before the main symptoms mentioned above.

The course of the infection

In most cases of glandular fever, the symptoms will resolve within two to three weeks of the initial infection. Your sore throat will be at its worst for three to five days after symptoms start before gradually improving, and your fever will usually last 10 to 14 days.

Fatigue is the most persistent symptom and can last for several weeks. However, some people may feel persistently fatigued for several months.

When to seek medical advice

You should contact your GP if you suspect that you or your child has developed glandular fever.

While there is little that your GP can do in terms of treatment other than provide advice and support, blood tests may be needed to rule out less common but more serious causes of your symptoms, such as hepatitis (a viral infection that can cause liver disease).

You should go to your local accident and emergency (A&E) department or dial 999 for an ambulance if you have glandular fever and you:

  • develop a rasping breath (stridor) or have any breathing difficulties
  • find swallowing fluids difficult
  • develop intense abdominal pain

If you have these symptoms, you may need to be looked after in hospital for a few days.

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Glandular fever is caused by the Epstein-Barr virus (EBV). EBV is most often spread through the saliva of someone who carries the infection.

For example, it can be spread through:

  • kissing - glandular fever is sometimes referred to as the "kissing disease"
  • sharing food and drinks
  • sharing toothbrushes
  • exposure to coughs and sneezes

Small children may be infected by chewing toys that have been contaminated with the virus.

When you come into contact with infected saliva the virus can infect the cells on the lining of your throat.

The infection is then passed to white blood cells before spreading through the lymphatic system. This is a series of glands (nodes) found throughout your body that allows many of the cells that your immune system needs to travel around the body.

After the infection has passed, people develop lifelong immunity to the virus and most won't develop symptoms again.

Many people are first exposed to EBV during childhood, when the infection causes few symptoms and often goes unrecognised before it eventually passes.

Young adults may be most at risk of glandular fever because they might not have been exposed to the virus when they were younger, and the infection tends to produce more severe symptoms when you're older.

EBV carriers

Not everyone who can pass on EBV will have symptoms themselves. These are known as asymptomatic carriers.

Some people can have the virus in their saliva for a few months after recovering from glandular fever, and may continue to have the virus in their saliva on and off for years.

This is because the virus remains inactive in the body for the rest of your life after you have been exposed to it. For most people, the inactive virus won't cause any symptoms.

However, there is a chance of the virus periodically becoming reactivated, which may mean it re-enters the saliva. This reactivation may be without any symptoms, or it may cause symptoms to recur for a short time.

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There is currently no cure for glandular fever, but the symptoms should pass within a few weeks. However, there are things you can do to help control your symptoms.


It is important to drink plenty of fluids (preferably water or unsweetened fruit juice) to avoid becoming dehydrated.

Avoid alcohol, as this could damage your liver, which will already be weakened from the infection.


Painkillers available over the counter such as paracetamol, or non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, can help relieve symptoms of pain and fever.

Children under 16 years old should not take aspirin. There is a small risk it could trigger a rare but serious health condition called Reye's syndrome.

Regularly gargling with a solution of warm, salty water may also help relieve your sore throat.


It is important you take plenty of rest while you recover from glandular fever. However, complete bed rest is no longer recommended, as it can make the symptoms of fatigue last longer.

You should gradually increase your activities as your energy levels return, but it is important to avoid activities you cannot manage comfortably.

For the first month after your symptoms begin, avoid contact sports or activities that put you at risk of falling. This is because if you have a swollen spleen, it is more vulnerable to damage and a sudden knock could cause it to rupture.

Preventing the spread of infection

There is no need to be isolated from others if you have glandular fever as most people will already be immune to the Epstein-Barr virus (EBV).

You can return to work, college or school as soon as you feel well enough. There is little risk of spreading the infection to others as long as you follow commonsense precautions, such as not kissing other people or sharing utensils.

It is also important to thoroughly clean anything that may have been contaminated by saliva until you have recovered.

Antibiotics and steroids

Antibiotics are not effective in treating glandular fever because they have no effect on viral infection. However, antibiotics may be prescribed if you also develop a bacterial infection of the throat or lungs (pneumonia).

A short course of steroids may also be prescribed if

  • your tonsils are particularly swollen or causing breathing difficulties.
  • you have severe anaemia – a lack of oxygen-carrying red blood cells
  • you have problems affecting your heart, such as pericarditis (inflammation of the sace that surrounds the heart)
  • you have problems affecting your brain or nerves, such as encephalitis

Hospital treatment

Most people are able to recover from glandular fever at home, but hospital treatment may be necessary for a few days if you or your child:

  • develop a rasping breath (stridor) or have any breathing difficulties
  • find swallowing fluids difficult
  • develop intense abdominal pain

Treatment in hospital may involve receiving fluids or antibiotics directly into a vein (intravenously), corticosteroid injections and pain relief.

In a small number of cases, emergency surgery to remove the spleen (splenectomy) may be needed if it ruptures

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Most people with glandular fever will recover in two or three weeks and won't experience any further problems.

However, complications can develop in a few cases. Some of the main complications associated with the condition are described below.

Prolonged fatigue

More than one in 10 of people with glandular fever will experience prolonged fatigue, which lasts for six months or more after the initial infection. It is not known why fatigue lasts longer in some people.

Some experts think that it may be a form of chronic fatigue syndrome (CFS). This is a poorly understood condition that causes fatigue and a range of other symptoms, such as headaches and joint pain.

Adopting a gradual exercise plan to rebuild your strength and energy levels may help to prevent and reduce prolonged fatigue.

Reduction in Blood cells

In a few cases, glandular fever can lead to a reduction in some blood cells. It can reduce levels of:

  • red blood cells (anaemia), which can make you feel tired and out of breath
  • white blood cells (neutropenia), which can make you more prone to developing a secondary infection
  • platelets, which can make you bruise and bleed more easily

In most cases, the reduction in the amount of blood cells is minimal and only causes mild symptoms. These problems should get better by themselves within a few weeks or months.

Ruptured spleen

Around half of people who develop glandular fever will have a swollen spleen. A swollen spleen does not present any immediate health problems, but is at risk of rupturing (bursting). The main sign of a ruptured spleen is sudden sharp abdominal (tummy) pain.

Go to your local accident and emergency (A&E) department or dial 999 for an ambulance if you have glandular fever and you develop abdominal pain.

In some cases, emergency surgery may be required to remove an enlarged or ruptured spleen (splenectomy).

A ruptured spleen usually occurs as a result of damage caused by vigorous physical activities, such as contact sports. It is therefore very important to avoid these activities for at least a month after the symptoms of glandular fever begin.

Be particularly careful during the second and third week of your illness, as this is when the spleen is most vulnerable.

Neurological complications

In less than 1 in every 100 cases, the Epstein-Barr virus (EBV) can affect a person's nervous system and trigger a range of neurological complications, including:

  • Guillain-Barré syndrome – the nerves become inflamed, causing symptoms such as numbness and temporary paralysis
  • Bell's palsy – causes temporary weakness or paralysis of the muscles on one side of the face
  • viral meningitis – an infection of the protective membranes that surround the brain and spinal cord (although unpleasant, viral meningitis is much less serious than bacterial meningitis, which is life-threatening)
  • encephalitis – an infection of the brain

These complications will often need specific treatment, but more than four out of every five people with them will make a full recovery.

Secondary infection

In a small number of glandular fever cases, the initial infection weakens your immune system and allows bacteria to infect parts of the body. This is called a secondary bacterial infection

Possible secondary infections arising from glandular fever include serious conditions such as pneumonia (infection of the lung) and pericarditis (infection of the sac that surrounds the heart).

Secondary infections usually only occur in people who have a weakened immune system, such as people with HIV or AIDS or those undergoing high-dose chemotherapy.

If you have a weakened immune system and you develop glandular fever, as a precaution you may be referred to hospital for specialist treatment. This will enable your health to be carefully monitored and any secondary infection to be treated.


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The information on this page has been adapted by NHS Wales from original content supplied by NHS Choices.
Last Updated: 03/10/2016 08:44:46