Clinical Guides
Glandular Fever (Infectious Mononucleosis)
A clinically focused clinical guide to recognising, confirming and safely managing Epstein-Barr virus infectious mononucleosis, including important mimics, airway and splenic risk, hepatitis, activity advice and the Indian care context.
MedNext Academy | 14 min read
Glandular Fever (Infectious Mononucleosis)
A clinically focused clinical guide to recognising, confirming and safely managing Epstein-Barr virus infectious mononucleosis, including important mimics, airway and splenic risk, hepatitis, activity advice and the Indian care context.
Summary
Glandular fever, or infectious mononucleosis, is a clinical syndrome most often caused by primary Epstein-Barr virus (EBV) infection. Fever, pharyngitis, fatigue and lymphadenopathy are typical, but no single feature establishes the diagnosis. Posterior cervical nodes, palatal petechiae, tonsillar enlargement or exudate, atypical lymphocytosis and mild transaminase elevation make EBV more likely. Children may have mild or unrecognised infection; adolescents and young adults are more likely to develop the classic syndrome. EBV persists lifelong after infection, and salivary shedding can continue intermittently, so a rigid isolation period is neither practical nor evidence based.
Most immunocompetent patients improve with hydration, analgesia, rest and a gradual return to usual activity. Antibiotics do not treat EBV. Ampicillin or amoxicillin commonly triggers a prominent rash during acute mononucleosis and should be avoided when the syndrome is suspected unless a separate, compelling bacterial indication has been established. Routine antivirals and routine systemic corticosteroids do not shorten uncomplicated illness sufficiently to justify their harms. Steroids are reserved for selected severe complications, such as impending upper-airway obstruction or serious immune-mediated cytopenia, with specialist oversight.
Safety depends on recognising threatened airway, dehydration, severe hepatitis, neurological disease and splenic rupture. Splenomegaly can be clinically occult. Contact sport, collision risk and heavy lifting are avoided during the early vulnerable period, followed by individual clinical clearance rather than reassurance based only on feeling better. Atypical, persistent or high-risk presentations require reconsideration of HIV, cytomegalovirus, streptococcal pharyngitis, diphtheria where relevant, haematological malignancy and other causes of a mononucleosis-like illness.
How Common Is It?
EBV infection is extremely common worldwide. CDC laboratory guidance notes that more than 90% of adults show antibodies from past infection, but past seropositivity is not the same as current glandular fever. Infection acquired in early childhood is frequently asymptomatic or nonspecific; primary infection delayed until adolescence or young adulthood is more likely to produce infectious mononucleosis. CDC patient guidance estimates that at least one in four teenagers or young adults who acquire EBV develop the syndrome. These figures describe broad populations and should not be converted into a patient-specific probability.
The apparent frequency varies with age, living conditions, household crowding, testing practice and the threshold for seeking care. In India, many people acquire EBV during childhood, so the classic adolescent syndrome may be less visible than in populations where primary infection occurs later. That epidemiological pattern does not make EBV rare, exclude severe adolescent disease or justify diagnosing every exudative sore throat as bacterial. Reliable contemporary, nationally representative Indian incidence data for symptomatic infectious mononucleosis are limited; clinic series and seroprevalence studies cannot provide a single current national rate.
The practical denominator is therefore the patient with a compatible syndrome, not a headline prevalence. Consider EBV when prolonged fever, marked fatigue, generalised or posterior cervical lymphadenopathy, pharyngitis, splenic enlargement or atypical lymphocytes cluster together. Conversely, common exposure and high background antibody prevalence mean that isolated EBV IgG does not prove the current illness. A diagnostic test must be interpreted against timing, symptoms and the full antibody pattern. Incidence statements also do not predict complication risk: splenic rupture and airway obstruction are uncommon, yet consequential enough to justify explicit counselling and safety-netting.
Risk Factors
The principal determinant of the classic syndrome is the age at primary EBV infection. Adolescents and young adults are more likely than young children to develop fever, exudative pharyngitis, lymphadenopathy and prolonged fatigue. Close salivary contact increases opportunity for transmission: kissing and sharing drinks, utensils, toothbrushes or other saliva-contaminated items are plausible routes. EBV can be shed before symptoms and intermittently after recovery, so the source is often unknowable. Stigma about kissing should be avoided; glandular fever is not proof of any particular behaviour. There is no licensed preventive vaccine in routine use.
Risk of a complicated course is not identical to risk of acquiring infection. Marked tonsillar hypertrophy raises concern for upper-airway compromise. Splenomegaly, collision sport, heavy lifting, abdominal trauma and an early return to strenuous training increase concern for splenic injury. Significant vomiting or painful swallowing increases dehydration risk. Pre-existing liver disease, alcohol exposure or hepatotoxic medicines complicate interpretation and management of hepatitis. Pregnancy does not by itself make EBV a classic congenital-infection emergency, but diagnostic alternatives and medicine safety still require obstetric context.
Immunocompromise changes the frame. Transplant recipients, people receiving substantial immunosuppression and those with advanced HIV can have atypical EBV disease or EBV-associated lymphoproliferation; a simple community pathway may be unsafe. A mononucleosis-like illness can also be acute HIV, CMV, toxoplasmosis, viral hepatitis or another infection. Sexual exposure, injection exposure, transfusion history, pregnancy, travel, vaccination status and local outbreaks guide testing without moral judgement. Persistent nodes, weight loss, drenching sweats, unexplained cytopenias, organ enlargement or an abnormal blood film require consideration of leukaemia or lymphoma rather than repeated presumptive treatment for infection.
Diagnosis
History
Establish symptom onset and sequence. Ask about fever, sore throat, odynophagia, inability to swallow saliva, voice change, snoring or breathing difficulty; fatigue; headache; rash; jaundice, dark urine or pale stool; and left upper-quadrant, shoulder-tip or generalised abdominal pain. Document school, work, exercise, collision sport and heavy lifting. Ask about recent antibiotics, especially aminopenicillins, and distinguish a delayed maculopapular eruption from immediate urticaria, angioedema or anaphylaxis. Record sexual and blood-borne-virus risk sensitively, drug exposure, immunosuppression and relevant contacts.
Examination
Assess airway, voice, respiratory effort, hydration, temperature, pulse and haemodynamic state first. Examine the oropharynx for tonsillar enlargement, exudate, asymmetry, uvular displacement, palatal petechiae and drooling. Palpate cervical, axillary and inguinal nodes, noting posterior cervical predominance, tenderness, fixation and size. Examine for rash, petechiae, pallor and jaundice. Gently assess liver and spleen, recognising that physical examination has limited sensitivity and repeated vigorous palpation is inappropriate. Look for meningism, focal neurology or other organ involvement when symptoms indicate.
Investigations
A full blood count with differential and blood film may show lymphocytosis and atypical lymphocytes; platelet or neutrophil reduction can occur. Liver enzymes are often mildly abnormal. Testing is selective in a typical mild illness but useful when confirmation changes counselling, the presentation is atypical or complications are suspected. Heterophile antibody tests can be falsely negative early and perform poorly in young children; CDC does not recommend Monospot for general confirmation. EBV viral capsid antigen IgM with absent EBV nuclear antigen supports primary infection; VCA IgG plus EBNA usually indicates past infection. Order targeted HIV antigen/antibody or RNA testing, CMV testing, throat testing for group A streptococcus, hepatitis studies or imaging according to the differential. Ultrasound is not a routine clearance test and spleen size alone cannot eliminate rupture risk.
Differential Diagnosis
Group A streptococcal pharyngitis can produce fever, tonsillar exudate and tender anterior cervical nodes, but cough absence or exudate alone cannot separate it reliably from EBV. Use an age-appropriate validated sore-throat assessment and microbiological testing where it will change antibiotics. Coinfection is possible but should not be assumed from colonisation. Peritonsillar abscess is suggested by unilateral severe pain, trismus, a muffled voice, uvular deviation or asymmetric swelling; retropharyngeal infection, epiglottitis and diphtheria are airway threats with context-specific signs and require urgent action.
CMV commonly causes a heterophile-negative mononucleosis-like illness with fever, fatigue and hepatitis but often less prominent pharyngitis. Acute HIV can resemble mononucleosis with fever, rash, pharyngitis, diarrhoea, mucocutaneous ulceration or generalised nodes; a negative antibody-only test very early after exposure does not reliably exclude it. Testing must follow the exposure window and current national algorithm, with confidential counselling. Toxoplasmosis, rubella, adenovirus, influenza, COVID-19 and viral hepatitis enter the differential according to exposure and organ pattern.
Haematological disease must remain visible. Leukaemia or lymphoma may cause fever, nodes, cytopenias, hepatosplenomegaly and atypical circulating cells. Hard, fixed, supraclavicular or progressively enlarging nodes; bone pain; bruising; persistent constitutional symptoms; or an abnormal film merit urgent evaluation. Drug reactions can cause fever, rash, lymphadenopathy, eosinophilia and liver injury. Autoimmune disease is less common but relevant when multisystem features persist. A positive past-infection EBV antibody pattern must not close this differential, because it is expected in most adults and may be incidental.
Management
Uncomplicated disease is managed supportively. Explain the expected course without promising a fixed recovery date: fever and throat symptoms often improve over two to four weeks, whereas fatigue and exercise tolerance may recover more slowly. Encourage adequate oral fluid, small frequent drinks when swallowing hurts, appropriate nutrition and sleep. Paracetamol or an NSAID can be considered after checking age, pregnancy, renal and hepatic function, gastrointestinal risk, asthma sensitivity and interacting medicines. Avoid aspirin in children and adolescents. Salt-water gargles or simple throat measures may help comfort but do not alter viral persistence.
Antibiotics are not indicated for EBV itself. Treat proven or strongly supported bacterial infection according to local antimicrobial guidance; avoid ampicillin and amoxicillin when infectious mononucleosis is likely because a widespread rash can occur. Routine aciclovir or related antivirals suppress shedding transiently without convincing clinical recovery benefit and are not recommended for uncomplicated illness. Cochrane evidence is insufficient to support systemic corticosteroids for routine symptom control. A specialist may use corticosteroids for impending airway obstruction, severe immune haemolysis, profound thrombocytopenia or another defined complication, with monitoring and without allowing temporary symptom improvement to delay airway planning.
Give written safety-netting. The patient should avoid collision/contact sport, strenuous exertion and heavy lifting for at least the early three-to-four-week period described by WHO, and longer when symptoms, examination, sport or clinical judgement warrant. Return is graded: daily activity first, then light non-contact exercise only when afebrile and clinically well, and collision exposure only after individual clearance. Routine ultrasound cannot certify zero risk. Reduce alcohol while symptomatic and until liver inflammation has resolved. Arrange reassessment when symptoms worsen, oral intake is poor, jaundice appears, fatigue remains disabling, blood abnormalities are substantial or the diagnosis remains uncertain.
Prescribing Information
No medicine eradicates uncomplicated EBV infectious mononucleosis. When recommending paracetamol, calculate the total exposure from all combination cold, flu and analgesic products, follow the current Indian product label, and use extra caution with low body weight, malnutrition, alcohol excess or hepatic injury. NSAIDs may be unsuitable in dehydration, kidney disease, peptic ulceration, anticoagulation, platelet reduction, some asthma phenotypes and later pregnancy. The guide intentionally omits patient-specific doses; age, weight, organ function and the exact formulation matter.
Do not label the aminopenicillin-associated eruption automatically as lifelong IgE-mediated penicillin allergy. Record timing, morphology, mucosal involvement, systemic features and the exact drug. Immediate hives, bronchospasm, hypotension or angioedema remains an allergy emergency; blistering, mucosal erosion, skin pain or systemic deterioration raises concern for a severe cutaneous reaction. After recovery, a specialist drug-allergy assessment may clarify whether beta-lactams can be used in future. If group A streptococcus is confirmed, choose a non-aminopenicillin regimen compatible with current local guidance and the allergy history rather than improvising.
Systemic corticosteroids are not a routine sore-throat prescription in glandular fever. Evidence of short-lived symptom benefit is uncertain, adverse-event reporting is weak, and immunosuppression can complicate infection assessment. When a specialist identifies a serious indication, document the indication, airway plan, glucose and infection risks, duration and review. Antivirals are likewise not routine. Avoid unreviewed herbal mixtures or supplements marketed as liver cures; composition and hepatotoxicity may be uncertain. Review other hepatotoxic agents and alcohol individually rather than stopping essential medicines indiscriminately. Pregnancy, breastfeeding, childhood, immunocompromise and significant hepatic or renal dysfunction require medicine-specific advice from current references.
When to Refer
Emergency referral is required for stridor, severe respiratory effort, rapidly progressive tonsillar swelling, inability to swallow saliva, drooling, cyanosis, exhaustion or a muffled voice with concern for airway obstruction. Do not send an unstable patient by private transport or delay transfer for outpatient testing. Severe left upper-quadrant or generalised abdominal pain, shoulder-tip pain, collapse, tachycardia, pallor or hypotension may indicate splenic rupture and requires immediate resuscitation and surgical assessment. Encephalopathy, meningism, seizure, focal deficit, severe weakness or cardiorespiratory involvement also warrants urgent hospital care.
Same-day assessment is appropriate for inability to maintain hydration, significant jaundice, repeated vomiting, severe pain, rapidly spreading rash with systemic illness, major bleeding, symptomatic anaemia or concerning cytopenia. Consider medical, infectious-disease, haematology, ENT, critical-care or surgical input according to the complication. Immunocompromised patients, transplant recipients and people with suspected acute HIV need a lower threshold for specialist advice because the disease spectrum and testing strategy differ.
Routine specialist referral is not necessary for a steadily recovering uncomplicated case. Refer or investigate further when fever, nodes, cytopenias, hepatitis or disabling symptoms persist beyond the expected trajectory; when lymph nodes are hard, fixed, supraclavicular or enlarging; when the diagnosis remains uncertain; or when return to high-risk professional or competitive sport needs individualized expertise. A clinician should review substantial liver-test abnormalities until improving. Access constraints must not downgrade urgency: where EBV serology or imaging is unavailable, transfer decisions are based on physiology, airway, abdominal findings and blood results rather than waiting for definitive virology.
Red Flags
Airway red flags are noisy or difficult breathing, stridor, drooling, inability to swallow secretions, rapidly increasing neck or tonsillar swelling, altered voice, cyanosis, reduced consciousness and fatigue from respiratory effort. Severe dehydration may present with minimal urine, postural symptoms, tachycardia, dry mucosa or inability to drink. Tonsillar exudate does not make an airway safe; repeated reassessment matters when swelling is evolving. Unilateral swelling, trismus or uvular displacement suggests a deep or peritonsillar collection rather than uncomplicated symmetrical pharyngitis.
Splenic rupture can occur without a remembered major collision. Sudden left upper-quadrant pain, pain referred to the left shoulder, abdominal guarding, dizziness, syncope, pallor, tachycardia or hypotension demands emergency evaluation. Do not be falsely reassured by absence of previously palpable splenomegaly. Jaundice, marked right upper-quadrant pain, confusion, bleeding or rapidly worsening liver tests suggests more than mild EBV-associated hepatitis. Petechiae, mucosal bleeding, severe pallor or breathlessness may signal clinically important thrombocytopenia or haemolysis.
Neurological red flags include severe headache with neck stiffness, seizure, confusion, focal weakness, cranial neuropathy, ataxia or ascending weakness. Persistent fever, night sweats, weight loss, progressive organ enlargement, abnormal cells on film or worsening multi-lineage cytopenia requires urgent exclusion of malignancy or another systemic disorder. A rash with mucosal erosions, blistering, facial oedema, organ dysfunction or hypotension is not the expected simple aminopenicillin eruption. Finally, a negative early heterophile test is not a safety signal: if the clinical course is worsening, revisit EBV-specific serology and the entire differential rather than repeating reassurance.
Indian Clinical Context
In India, glandular fever is encountered across primary care, college clinics, paediatrics, general medicine, emergency care and ENT. Earlier childhood EBV acquisition may reduce the proportion with a textbook adolescent syndrome, while access to EBV-specific serology varies widely. A syndromic diagnosis may be reasonable in a stable typical case, but limited testing must not become diagnostic certainty. A full blood count, differential, blood film and liver tests are often more accessible and can identify atypical lymphocytosis, cytopenia or hepatitis. Laboratory availability, cost and turnaround should be discussed transparently.
Exudative sore throat creates pressure for antibiotic prescribing. Antimicrobial stewardship requires separation of suspected EBV from group A streptococcus and dangerous bacterial throat disease, using clinical assessment and available testing. Do not prescribe an aminopenicillin merely because exudate is present. Where diphtheria immunisation is incomplete, a compatible adherent membrane or outbreak context changes infection-control and public-health action. Tuberculosis is not a cause of acute classic mononucleosis, but chronic nodes, weight loss and epidemiological risk require a separate pathway. Confidential HIV testing should be offered when the presentation or exposure warrants it; avoiding the subject is unsafe and stigmatising.
Advice must fit a patient's reality. Students, manual workers, military or police trainees, farmers and athletes may face collision or lifting exposure that cannot be described simply as return to school. Provide a written restriction and staged return plan. Remote patients need clear instructions on where emergency airway or abdominal care is available. Explain that prolonged fatigue is real, but repeated tonics, unnecessary antibiotics and unsupervised steroids are not evidence-based recovery strategies. Public and private referral options, travel distance, out-of-pocket costs and follow-up feasibility should be incorporated without lowering safety thresholds.
NMC Competency Mapping
This guide supports integrated undergraduate outcomes rather than claiming that one national code captures the whole syndrome. In medicine and paediatrics, learners should be able to obtain a focused fever and sore-throat history, assess hydration and airway, identify lymphadenopathy and hepatosplenomegaly, interpret a blood count, smear and liver profile, formulate infectious and haematological differentials, and initiate supportive treatment. Microbiology learning includes EBV transmission, latency, heterophile testing and interpretation of VCA IgM, VCA IgG and EBNA antibodies. Pharmacology outcomes include rational analgesic use, antimicrobial stewardship, adverse drug eruptions and the limited indications and harms of corticosteroids.
Community-medicine and professionalism outcomes include confidential risk assessment, appropriate HIV testing, infection-prevention advice, rational use of diagnostics and timely referral across levels of care. Emergency competencies include recognising threatened airway, shock and acute abdomen. Communication is central: counsel about salivary spread without stigma, recovery uncertainty, activity restrictions, warning symptoms and the difference between EBV infection, past antibody positivity and active mononucleosis.
Teaching should use observable tasks. A learner can present a problem representation, compare EBV with streptococcal pharyngitis, CMV and acute HIV, select investigations based on illness timing, interpret common serological patterns, construct an airway and splenic safety-net, and prescribe or withhold medicines safely. Exact competency identifiers and wording must be checked against the institution's current NMC CBME curriculum edition before recording completion; code numbering can change between curriculum documents. The mapped domains are clinical reasoning, microbiological diagnosis, pharmacotherapeutics, emergency recognition, communication, ethics and health-system navigation, not memorisation of a single test.
Key Exam Pearls for NEET PG
The classic triad is fever, pharyngitis and lymphadenopathy, with posterior cervical nodes particularly suggestive. Palatal petechiae, splenomegaly, atypical lymphocytes and mild hepatitis reinforce the pattern but are neither individually necessary nor sufficient. EBV is a double-stranded DNA herpesvirus that establishes latency in B lymphocytes. Atypical lymphocytes seen in blood are predominantly reactive CD8-positive T cells responding to infected B cells, a frequent examination distinction. Heterophile antibodies can be negative early and are less reliable in young children.
For serology, VCA IgM appears early and usually disappears within weeks; VCA IgG appears during acute infection and persists for life. EBNA antibody is generally absent in primary acute infection and appears later. Therefore VCA IgM positive with EBNA negative supports primary infection, while VCA IgG plus EBNA commonly signifies remote infection. A high EBV IgG titre alone does not date the illness. If an apparent mononucleosis syndrome is heterophile negative, think of CMV, acute HIV and toxoplasmosis as well as early EBV.
Ampicillin or amoxicillin during EBV illness can provoke a diffuse maculopapular rash; it does not automatically prove permanent penicillin allergy. Routine antibiotics, antivirals and corticosteroids are not treatments for uncomplicated disease. Steroids are reserved for serious complications such as impending airway obstruction or selected immune cytopenias. Splenic rupture presents with abdominal or referred shoulder pain and shock; palpation can miss splenomegaly. Avoid contact sport and heavy lifting during the early vulnerable period, then use individualized clearance. Exudate does not distinguish EBV from streptococcus, and a negative early test never overrides a deteriorating airway.
Frequently Asked Questions
Does a positive EBV IgG result prove that my current sore throat is glandular fever?
No. More than 90% of adults have evidence of previous EBV infection, and VCA IgG usually persists for life. Acute primary infection is supported by the clinical syndrome and an appropriate pattern, commonly VCA IgM present with EBNA absent. The timing of sampling matters, and a past-infection pattern should prompt the clinician to assess other causes of the current illness.
When can someone return to the gym, heavy work or contact sport after glandular fever?
There is no single clearance date that makes rupture risk zero. WHO advises avoiding contact sport and heavy lifting for at least three to four weeks, but return should also consider symptom onset, clinical recovery, abdominal symptoms, examination, the sport or job and specialist advice where risk is high. Start with normal daily activity, then light non-contact exercise, and seek urgent care for abdominal or shoulder-tip pain.
Does an amoxicillin rash during glandular fever mean lifelong penicillin allergy?
Not necessarily. A delayed widespread maculopapular rash is well recognised when aminopenicillins are given during acute EBV infection and is not identical to immediate IgE-mediated allergy. The exact timing, appearance and systemic features should be recorded. Hives, wheeze, hypotension, mucosal injury or blistering require urgent assessment. Formal drug-allergy evaluation after recovery may clarify future beta-lactam use.
Are steroids or antiviral medicines useful for routine glandular fever symptoms?
Routine use is not supported. Cochrane reviews found insufficient reliable benefit for corticosteroid symptom control and no convincing recovery benefit from antivirals in uncomplicated illness. Supportive care is standard. A specialist may use a corticosteroid for a defined severe complication such as impending airway obstruction or serious immune-mediated cytopenia; that decision requires monitoring and does not replace airway or emergency management.
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