What are the first signs of glandular fever?

Glandular fever, also called infectious mononucleosis, often begins like a routine viral illness. Tiredness may feel out of proportion to your other symptoms, while a sore throat can become troublesome and swallowing may hurt. Fever and swollen glands in the neck may develop together. A glandular fever presentation can include swollen glands, but these symptoms also occur with other infections, so symptoms alone cannot confirm the cause. Some people have a gradual start and others notice several symptoms over a short period.

The tiredness can continue after the throat and fever begin to settle. A clinician may assess your throat, lymph nodes and general condition, then decide whether a blood test is useful.

Rest, drink fluids regularly and choose soft foods if swallowing is uncomfortable. Avoid strenuous activity while you feel unwell, particularly if a clinician has concerns about an enlarged spleen. Arrange a GP consultation if symptoms are significant, worsening, or not beginning to improve. Keep a note of when the fever, sore throat, fatigue and swollen glands started, as the pattern helps with assessment.

Seek urgent medical help for difficulty breathing, inability to swallow fluids, severe dehydration, sudden severe abdominal pain, confusion or marked weakness. Contact a clinician promptly if a fever persists, the throat pain is severe, or you are struggling to function because of fatigue. Glandular fever can resemble other illnesses, so worsening symptoms deserve a fresh assessment.

You could ask whether your symptoms fit glandular fever, whether a blood test is appropriate, which activities to pause, and what changes should prompt urgent review. Ask when it is reasonable to return to work, study or exercise based on how you are recovering.