Overview
Mononucleosis is caused by Epstein-Barr virus and classically hits teens and young adults with severe fatigue, sore throat, and swollen lymph nodes. Fatigue can persist 4–8 weeks.
Symptoms to watch for
- Severe sore throat, often with white patches
- Extreme fatigue
- Fever
- Swollen lymph nodes in neck and armpits
- Enlarged spleen (tender left upper abdomen)
- Rash (especially if given amoxicillin by mistake)
What else could this be?
- Strep throat
- CMV or acute HIV infection
- Acute leukemia (rare)
How it's diagnosed
Monospot test or EBV antibody panel — often ordered with a strep swab to rule out both.
Treatment
Supportive: rest, fluids, ibuprofen. Avoid contact sports for at least 4 weeks due to spleen rupture risk. No specific antiviral.
When to book a visit
Book if a sore throat and severe fatigue have lasted more than a week.
Book online todayFrequently asked
How long does mono last?
Acute symptoms 2–4 weeks; fatigue often lingers 1–3 months.