Can infectious mononucleosis (mono) cause mouth sores?

Infectious Mononucleosis and Mouth Sores

Yes, infectious mononucleosis (mono) can cause mouth sores as part of its clinical presentation. Epstein-Barr virus (EBV), the primary cause of infectious mononucleosis, commonly affects the oral cavity during infection.

Clinical Manifestations of Oral Involvement in Mono

• Infectious mononucleosis typically presents with sore throat, which is one of the most common symptoms leading patients to seek medical attention 1, 2
• Oral manifestations include erythema and diffuse injection (redness) of the oral and pharyngeal mucosae 3
• Changes in the lips and oral cavity are characteristic features, including erythema, cracking lips, and a "strawberry tongue" 3
• The oral mucosa can develop ulcerations during EBV infection, contributing to the sore throat and pain when swallowing 2, 4

Distinguishing Features from Other Conditions

• Unlike bacterial pharyngitis (such as Group A Streptococcal infection), EBV-related oral lesions do not typically present with exudates 3
• The oral manifestations of mono are often accompanied by other classic symptoms including:
  • Fever (usually persisting for several days) 5, 2
  • Posterior cervical lymphadenopathy (swollen lymph nodes in the neck) 2
  • Fatigue 4
  • Potential hepatosplenomegaly (enlarged liver and spleen) 5

Diagnostic Considerations

• When evaluating mouth sores, infectious mononucleosis should be included in the differential diagnosis, particularly in adolescents and young adults aged 15-24 years 2
• Laboratory findings that support the diagnosis include:
  • Greater than 40% lymphocytes and greater than 10% atypical lymphocytes on complete blood count 2
  • Positive heterophile antibody test (sensitivity 87%, specificity 91%) 2
  • Elevated liver enzymes may increase clinical suspicion when heterophile test is negative 2

Management of Oral Manifestations

• Treatment of oral lesions in infectious mononucleosis is primarily supportive 2
• For painful oral lesions, consider:
  • Topical analgesics such as benzydamine hydrochloride rinses 3
  • Warm saline mouthwashes to cleanse the oral cavity 3
  • Topical anesthetics (e.g., viscous lidocaine 2%) for severe oral discomfort 3
  • Antiseptic oral rinses to reduce bacterial colonization of affected mucosa 3

Complications and Special Considerations

• While usually self-limiting, infectious mononucleosis can occasionally lead to severe complications including upper airway obstruction 1
• Complications may develop in up to 5% of patients with infectious mononucleosis 6
• Immunosuppressed populations are at higher risk for severe disease and significant morbidity 2
• The symptoms typically resolve within a few weeks, though protracted courses can occur 5

Prevention of Transmission

• EBV is primarily transmitted through saliva ("kissing disease") 5, 2
• Avoiding sharing of utensils, drinks, and close personal contact can help prevent transmission during active infection 2

In summary, mouth sores are a recognized manifestation of infectious mononucleosis caused by EBV infection. These oral lesions, along with other classic symptoms, help distinguish mono from other causes of pharyngitis and oral mucosal disease.