The incubation period for this infection is about 4-8weeks (1).
Infants and young children may be asymptomatic or present with mild symptoms that are often difficult to recognize (2).
The classic triad of symptoms in glandular fever consists of (3,4):
- fever
- sore throat
- lymphadenopathy
- posterior cervical adenopathy (1)
- axillary adenopathy
- inguinal adenopathy
Other clinical features seen in a patient with IM include:
- prodromal symptoms like chills, sweats, anorexia, fatigue, malaise, myalgias, headaches and abdominal fullness
- splenomegaly (soft) – seen in 50-60% of cases, peaks in the second week and resolves over the next 7–10 days (3)
- there may be a petechial haemorrhagic covering of the soft palate and whitish exudate covering the tonsils; the latter two features are suggestive of diphtheria
- a fine macular rash develops in nearly all adults (less common in children) 5 to 10 days after starting treatment with ampicillin, amoxicillin, or other beta-lactam antibiotics. This is not a true penicillin allergy and resolves in a few days after discontinuing the antibiotic (4)
- periorbital oedema (2)
- hepatomegaly – seen in 10-15% (3)
- jaundice (3)
Older adults are less likely to have sore throat and adenopathy but more likely to have hepatomegaly and jaundice (5)
References:
- Vouloumanou EK, Rafailidis PI, Falagas ME. Current diagnosis and management of infectious mononucleosis. Curr Opin Hematol. 2012 Jan;19(1):14-20
- Charles PGP. Infectious mononucleosis. Australian Family Physician 2003;32(10)
- Auwaerter PG. Recent advances in the understanding of infectious mononucleosis: are prospects improved for treatment or control? Expert Rev Anti Infect Ther. 2006 Dec;4(6):1039-49.
- Mergoum AM. Amoxicillin rash in infectious mononucleosis. N Engl J Med. 2021 Sep 9;385(11):1033.
- Drebber U, Kasper HU, Krupacz J, et al. The role of Epstein-Barr virus in acute and chronic hepatitis. J Hepatol. 2006 May;44(5):879-85.