Glandular Fever (Infectious Mononucleosis) in Singapore

Written & reviewed by the BestDoctors.sg editorial team · Last updated 1 Sep 2026 · General information, not medical advice

Glandular fever is the classic “exhausting sore throat that won’t quit” of the teens and twenties. Most people recover fine – the key is the two safety catches around antibiotics and the spleen.

What it is

Glandular fever is a viral infection, and in most cases the virus responsible is the Epstein-Barr virus (EBV) – one of the most common viruses in the world, and a member of the herpesvirus family. The name “infectious mononucleosis” comes from the changes seen in white blood cells during the illness. It is nicknamed the “kissing disease” because it passes so readily through saliva. A great many adults have been infected with EBV at some point, often without ever realising it, because young children who catch it may have only a mild, cold-like illness. When infection happens for the first time in the teenage years or twenties, however, it tends to produce the full-blown, exhausting picture that people recognise as glandular fever. Once you have had it, the virus stays dormant in the body for life but does not usually cause further trouble, and you are generally protected from getting glandular fever again.

How it spreads

EBV lives in saliva, so glandular fever spreads through close saliva contact: kissing; sharing cups, water bottles, straws, cutlery or toothbrushes; and coughs and sneezes at close range. It is contagious but far less easily caught than a cold or flu – brief, casual contact is unlikely to pass it on. The incubation period is long, roughly four to six weeks between catching the virus and feeling unwell, so the source is often not obvious and cannot usually be traced to one encounter. People can carry and shed the virus in saliva for weeks after they feel better, and intermittently for the rest of their lives, which is one reason the virus is so widespread. Simple habits – not sharing drinks or utensils, and covering coughs and sneezes – reduce the chance of passing it to others while you are unwell.

Who is at risk

Anyone who has not previously been infected with EBV can catch it, but the illness is overwhelmingly associated with teenagers and young adults, and it is common among students and others living or socialising in close quarters. Younger children are frequently infected too, but their illness is usually so mild it is mistaken for an ordinary viral cold. Older adults are much less likely to develop glandular fever, simply because most have already met the virus earlier in life and are immune. There is no vaccine, so avoiding saliva contact with someone who is unwell is the main way to reduce risk.

Symptoms

The classic triad is a high fever; a severe sore throat with markedly swollen tonsils, sometimes with a white coating; and swollen glands (lymph nodes), especially in the neck but sometimes in the armpits and groin as well. On top of this triad, marked and often prolonged tiredness is very characteristic, along with headache, aching muscles and a reduced appetite. Some people develop a swollen spleen or mild inflammation of the liver, which can occasionally cause mild jaundice (a yellow tinge to the skin or eyes). A rash can occur, and a widespread rash is especially likely if certain antibiotics have been given (see below). Symptoms usually build up over a few days; the fever and sore throat tend to ease within a couple of weeks, but the tiredness can linger for several weeks or even months as the body recovers, which many people find the most frustrating part of the illness.

The amoxicillin rash – why diagnosis matters

Because a severe sore throat is often assumed to be a bacterial (strep) throat, patients are sometimes given the antibiotics amoxicillin or ampicillin – which in glandular fever commonly trigger a widespread, itchy rash. This reaction is not a true, lasting penicillin allergy, but it is a very good reason to get the diagnosis right before treating a sore throat with antibiotics. If glandular fever is a possibility, a doctor will usually confirm it first and avoid these antibiotics. It is another reminder that a persistent, severe sore throat with fever and swollen glands in a young person deserves proper assessment rather than a guess.

Spleen safety – a red flag you must know

This is the most important safety point in glandular fever. Because the illness can cause the spleen to enlarge, there is a small but serious risk that it can rupture – occasionally with little or no injury, but especially after a blow, a fall or straining. To protect the spleen, doctors advise avoiding contact and collision sports, vigorous exercise and heavy lifting for several weeks, until a doctor confirms it is safe to return. Do not judge this yourself, as the spleen can stay enlarged after you otherwise feel better.

Call 995 or go to A&E immediately for sudden, severe pain in the upper-left tummy or the tip of the left shoulder, which can signal a ruptured spleen and is a medical emergency. Feeling faint, very pale or breathless alongside such pain makes urgent care even more important.

How it is diagnosed

Diagnosis is often clear from the typical picture – the age of the patient, the fever, the sore throat with swollen tonsils, the swollen neck glands and the striking tiredness. To confirm it and rule out other causes, a doctor may arrange blood tests. These include a specific test for glandular fever (a Monospot or EBV antibody/serology test) and a full blood count, which typically shows characteristic changes in the white blood cells. Liver blood tests are sometimes checked if the liver seems involved. A doctor will also examine the tummy to feel whether the spleen is enlarged. In Singapore, a GP or polyclinic can assess the illness and organise these tests, referring to a specialist if the picture is unusual or complications are suspected.

Complications

Most people recover without any problem, but it is worth knowing the possible complications. The most important is an enlarged spleen that can, rarely, rupture – the reason for avoiding contact sports and heavy lifting, as above. Other complications can include mild inflammation of the liver (sometimes with jaundice), a tonsil and throat so swollen that swallowing or breathing becomes difficult, and prolonged fatigue that outlasts the other symptoms. A separate bacterial throat infection can occasionally develop on top of the viral one. And, as noted, giving amoxicillin or ampicillin can cause a widespread rash, which is why a doctor should confirm the diagnosis before treating a “sore throat.” More serious complications are uncommon, but they are the reason to seek help promptly if you are struggling to swallow, breathe or keep fluids down.

Treatment

There is no specific cure for glandular fever, and none is usually needed – the body clears the virus on its own. Care is supportive, aimed at easing symptoms while you recover: plenty of rest, plenty of fluids to stay well hydrated (especially with a fever and a sore throat), and paracetamol for fever and pain. Soothing measures for the throat, such as cool or warm drinks and rest for the voice, can help too. Antibiotics do not work, because glandular fever is caused by a virus, not bacteria; they are avoided unless there is a separate bacterial infection – and even then, amoxicillin and ampicillin are avoided because of the rash. In severe cases – for example, when the throat is so swollen it threatens breathing or swallowing – hospital care and additional treatment may be needed, so any such difficulty should be assessed by a doctor straight away.

Recovery and living with it

Recovery is usually complete, but it can be gradual. The fever and sore throat often settle within a week or two, while the tiredness may last several weeks or longer. The best approach is to rest when you need to and return to normal activity gradually rather than all at once, listening to your body and building up as your energy returns. Keep drinking well, eat as you are able, and give yourself permission to take things slowly – pushing too hard too soon tends to prolong the fatigue. Crucially, keep avoiding contact sports and heavy lifting until a doctor confirms the spleen has returned to normal, even if you otherwise feel back to yourself. Most young people are back to their usual routine within a few weeks; if severe tiredness drags on well beyond that, it is worth seeing a doctor to review.

When to see a doctor

See a GP or polyclinic doctor if you have a severe or persistent sore throat with fever and swollen glands, particularly as a teenager or young adult, so the diagnosis can be confirmed and the right advice given about the spleen and antibiotics. Also see a doctor if a high fever will not settle, if you notice yellowing of the skin or eyes, or if tiredness is severe or dragging on. Reliable general health information is available through HealthHub.

Seek urgent or emergency care – call 995 or go to A&E – if there is:

• Sudden, severe pain in the upper-left tummy or the tip of the left shoulder – this can signal a ruptured spleen.
• Difficulty breathing or swallowing, or a throat so swollen it is hard to breathe.
• Being unable to drink enough fluids, or signs of dehydration such as passing little urine, dizziness or drowsiness.

Related infections & conditions

• COVID-19
• Chickenpox
• Hepatitis A
• Typhoid fever
• Chikungunya
• Sepsis
• Melioidosis
• Leptospirosis
• Norovirus
• Dengue fever
• Influenza (flu)
• Infectious disease specialists in Singapore

Sources

• NHS — glandular fever: cause (EBV), saliva spread, symptoms, self-limiting course, supportive care, urgent red flags.
• Peer-reviewed literature (PMC) — amoxicillin/ampicillin rash in mononucleosis; splenic enlargement/rupture risk.
• Geeky Medics — triad, incubation, Monospot/serology/FBC, avoid contact sports, penicillin rash.
• Singapore ENT clinical material — local presentation and management.