Can a sore throat from infectious mononucleosis last for weeks?

Sore Throat in Infectious Mononucleosis Can Last for Weeks

Yes, a sore throat from infectious mononucleosis typically lasts for weeks, unlike most other causes of pharyngitis which resolve within days. 1, 2

Characteristics of Mononucleosis-Related Sore Throat

• Infectious mononucleosis (IM) sore throat is one of the most common and characteristic symptoms, occurring in 70-92% of patients with the disease 1
• While typical viral or streptococcal pharyngitis symptoms resolve within 3-4 days (with or without antibiotics), the sore throat from IM can persist for several weeks 3, 2
• The pharyngitis in IM is often severe and may be accompanied by significant tonsillar enlargement, making it difficult to distinguish from bacterial pharyngitis based on clinical appearance alone 1, 4

Clinical Presentation and Differentiation

• IM pharyngitis is part of the classic triad of symptoms: fever, tonsillar pharyngitis, and lymphadenopathy 2
• Features that help differentiate IM from other causes of sore throat include:
  • More generalized lymphadenopathy (not just anterior cervical) 1
  • Significant fatigue that may persist for months 1, 2
  • Absence of cough and rhinorrhea (which are more common in viral pharyngitis) 1
  • Presence of periorbital/palpebral edema in about one-third of patients 2
  • Splenomegaly in approximately 50% of cases 2
  • Hepatomegaly in about 10% of cases 2
  • Maculopapular rash in 10-45% of patients 2

Time Course and Duration

• Unlike streptococcal pharyngitis, which typically resolves within one week (with most patients experiencing symptom improvement after 3-4 days), the sore throat from IM has a much longer duration 3, 5
• The prolonged course of IM symptoms, including sore throat, is characteristic of the disease and can last for several weeks 5, 2
• Fatigue associated with IM may be profound and typically resolves within three months 2

Diagnostic Considerations

• Complete blood count typically shows lymphocytosis (lymphocytes >50% of white blood cells) 2
• Atypical lymphocytes constitute more than 10% of the total lymphocyte count 2
• The monospot test (heterophile antibody test) is the most widely used diagnostic test with a sensitivity of 87% and specificity of 91% 6
• False-negative monospot results can occur in children under five years and in adults during the first week of illness 6
• Elevated liver enzymes increase clinical suspicion for IM when the heterophile antibody test is negative 6

Management Approach

• Treatment is mainly supportive as IM is generally self-limited 2, 6
• For symptom relief:
  • Analgesics like ibuprofen or paracetamol are recommended for relief of sore throat symptoms 7
  • Warm saline mouthwashes and topical anesthetics can help manage oral pain 1
• Reduction of activity and bed rest as tolerated are recommended 2
• Patients should avoid contact sports or strenuous exercise for 8 weeks or while splenomegaly is present to prevent splenic rupture 2, 6
• Routine use of antivirals and corticosteroids is not recommended 6

Potential Complications

• Spontaneous splenic rupture occurs in 0.1 to 0.5% of patients with IM and is potentially life-threatening 2
• Upper airway obstruction due to significant tonsillar enlargement can occur in severe cases 8, 4
• Hepatitis and other complications may develop during the course of illness 5
• IM is a risk factor for chronic fatigue syndrome 2

Important Pitfalls to Avoid

• Misdiagnosing IM as streptococcal pharyngitis, leading to unnecessary antibiotic treatment 1
• Using steroids for uncomplicated IM without clear indications (steroids should be reserved for impending airway obstruction or hematological complications) 8
• Allowing patients to return to contact sports too early, risking splenic rupture 2, 6
• Failing to recognize that a prolonged sore throat (>1 week) should raise suspicion for IM rather than typical viral or bacterial pharyngitis 3, 1