Glandular fever — infectious mononucleosis
Glandular fever (medically infectious mononucleosis, often called mono) is a viral illness most commonly caused by Epstein-Barr virus (EBV). It is especially common in teenagers and young adults — though many people catch EBV earlier in life with mild symptoms or none at all.
The illness is famous for severe tiredness that outlasts the sore throat — recovery is often measured in weeks to months, not days.
Symptoms
Typical presentation:
- severe sore throat — can mimic bacterial tonsillitis
- swollen lymph nodes — especially neck; may be armpits and groin too
- high temperature and flu-like aches
- profound fatigue — often the most disabling symptom
- swollen, puffy eyelids sometimes
- headache, loss of appetite
Less common:
- rash — especially if given amoxicillin or ampicillin before diagnosis
- jaundice — mild liver involvement (yellow skin/eyes)
- enlarged spleen — felt as fullness left upper abdomen
- enlarged liver
Not everyone gets all symptoms — some have mild sore throat and fatigue only.
How it spreads
EBV spreads through saliva:
- kissing
- sharing drinks, cups, or cutlery
- coughs and sneezes (less than flu)
The virus has a long incubation period — 4 to 6 weeks from exposure to symptoms.
You are most infectious when acutely unwell, but the virus can be shed for months — reason to avoid sharing utensils while ill.
Diagnosis
GP may diagnose clinically in a young person with classic features. Blood tests confirm:
- Monospot test — rapid but can be false negative early
- EBV serology — IgM and IgG antibodies
Full blood count often shows atypical lymphocytes — characteristic white cell pattern.
Throat swab may be done to exclude strep throat — glandular fever is viral, so antibiotics do not cure it (except the rash issue below).
Treatment — supportive care
No antiviral cure for EBV in otherwise healthy people. Treatment is:
- rest — listen to fatigue; do not push through
- fluids — prevent dehydration, especially if swallowing is painful
- paracetamol or ibuprofen — fever, pain, throat inflammation
- throat lozenges, warm drinks, ice lollies — comfort
- avoid alcohol — liver is often inflamed
Steroids — occasionally used for severe airway swelling — specialist decision only.
Do not take amoxicillin or ampicillin if glandular fever is suspected or confirmed — causes widespread rash in most EBV cases.
Complications — rare but important
| Complication | Notes |
|---|---|
| Splenic rupture | Life-threatening — avoid contact sport; seek emergency care for sudden severe left-sided abdominal pain |
| Airway obstruction | Massive tonsil swelling — rare; may need steroids or hospital |
| Severe hepatitis | Uncommon |
| Chronic fatigue | Post-viral fatigue syndrome in some — overlaps with long recovery |
| Secondary bacterial infection | Tonsillar bacterial superinfection — rare |
Sport and exercise — critical advice
Enlarged spleen is common and not always obvious on examination.
Avoid for at least 4 weeks from onset:
- rugby, football, martial arts, boxing
- heavy weightlifting
- any activity with abdominal trauma risk
Return to sport only when GP confirms spleen has returned to normal size if previously enlarged.
Glandular fever vs other illnesses
| Condition | How it differs |
|---|---|
| Strep tonsillitis | Often no marked fatigue; responds to antibiotics; no EBV rash with amoxicillin |
| COVID-19 / flu | Different pattern; test if suspected |
| Cytomegalovirus (CMV) | Similar mono-like illness — blood tests distinguish |
| HIV acute seroconversion | Mono-like illness — HIV test if risk factors |
| Lymphoma | Persistent painless nodes, night sweats, weight loss — GP excludes if doubt |
See our swollen glands guide if nodes persist beyond expected recovery.
Recovery timeline
Week 1 to 2: Peak symptoms — throat, fever, glands.
Week 2 to 4: Throat and fever usually improve; fatigue often worsens or plateaus.
Month 2 to 6: Gradual energy return — non-linear; good days and bad days.
Return to normal: Most fully recover within 2 to 3 months; a minority have fatigue longer — worth GP review if not improving by 4 months.
Practical tips
- University/work — explain illness; phased return beats crashing and relapsing
- Do not kiss or share utensils while acutely infectious
- Avoid alcohol until liver tests normal if jaundice occurred
- Sleep — fatigue is physiological, not laziness
Glandular fever is miserable but almost always self-limiting in healthy young people. Patience with fatigue, avoiding contact sport, and not taking inappropriate antibiotics are the keys to safe recovery.
Common questions about glandular fever
- How long does glandular fever last?
- Acute symptoms — sore throat, fever, swollen glands — usually improve over 2 to 4 weeks. Fatigue and tiredness often persist for weeks to months — sometimes up to 6 months — even after other symptoms resolve. Gradual return to normal activity is advised; rushing back often worsens fatigue.
- Is glandular fever the same as mono?
- Yes — infectious mononucleosis (mono) is the medical name; glandular fever is the common UK term. Both refer to the same illness, usually caused by Epstein-Barr virus.
- How do you catch glandular fever?
- Mainly through saliva — kissing (hence "kissing disease"), sharing cups or utensils, or coughs and sneezes. EBV is very common — many people are infected in childhood with mild or no symptoms. Teenagers and young adults more often get full glandular fever symptoms.
- Can you get glandular fever twice?
- Very rarely — EBV usually causes lifelong immunity after first infection. Fatigue relapses months later are common but are not reinfection — post-viral fatigue is part of recovery. Other viruses can cause similar illness.
- Why should you avoid sport with glandular fever?
- EBV enlarges the spleen — contact to the abdomen during sport can cause splenic rupture, a life-threatening bleed. Avoid contact sports, heavy lifting, and strenuous exercise for at least 4 weeks, longer if the spleen is still enlarged on examination.
- What is the glandular fever rash?
- A widespread red rash can occur if amoxicillin or ampicillin is given for presumed bacterial tonsillitis before EBV is diagnosed — not an allergic reaction in the usual sense but a characteristic interaction. Tell any doctor you have or may have glandular fever before taking antibiotics.
- Can glandular fever cause liver problems?
- Mild liver inflammation is common — slightly raised liver enzymes, sometimes mild jaundice. Usually resolves with recovery. Avoid alcohol while unwell. Severe hepatitis is rare.
- When can I return to school or work?
- When fever has gone and you feel able — often after 1 to 2 weeks for desk work or study. Physical jobs and sport need longer. Fatigue may limit full capacity for weeks — phased return helps.