Infectious mononucleosis (mono) and strep throat are distinct infections that frequently cause similar symptoms, leading to diagnostic uncertainty. Both can manifest with a sore throat, fever, and fatigue, making differentiation challenging based on symptoms alone. This article clarifies how these two infections relate, especially concerning testing and diagnosis.
Understanding Mono and Strep
Mono is a viral infection caused by the Epstein-Barr virus (EBV). It spreads through bodily fluids, most commonly saliva, earning it the nickname “kissing disease.” Symptoms appear four to six weeks after exposure and include extreme fatigue, fever, swollen lymph glands in the neck and armpits, and a sore throat, which may have white patches. While symptoms lessen within a few weeks, fatigue, swollen lymph nodes, and an enlarged spleen can persist for months.
Strep throat, in contrast, is a bacterial infection caused by Streptococcus pyogenes, also known as Group A Streptococcus. This bacterium is highly contagious and spreads through respiratory droplets or direct contact. Symptoms include a sore throat that develops quickly, painful swallowing, red and swollen tonsils (sometimes with white patches or pus), swollen lymph nodes in the neck, and fever. Headache, body aches, and nausea or vomiting may also occur.
Co-occurrence and Testing Implications
It is possible for an individual to have strep throat and mono simultaneously, a situation referred to as co-infection. Mono, a viral infection that can affect the immune system, may increase susceptibility to secondary bacterial infections like strep throat.
Diagnosing these conditions involves specific tests. A rapid strep test, performed by swabbing the back of the throat, quickly detects Streptococcus pyogenes bacteria. Results are available within minutes. For mono, a monospot test or an Epstein-Barr virus (EBV) antibody test detects the viral infection. A positive strep test indicates the presence of strep bacteria, regardless of whether mono is also present. This means a positive strep test requires appropriate treatment even if mono is suspected or confirmed.
Treatment and Management
When both strep throat and mono are present, treatment strategies address each infection while considering their interplay. Strep throat, a bacterial infection, requires antibiotic treatment to prevent complications like rheumatic fever or kidney inflammation. Commonly prescribed antibiotics include penicillin or amoxicillin.
A significant caution exists regarding antibiotic selection in co-infected patients. Amoxicillin or ampicillin should be avoided if mono is diagnosed or suspected, as these antibiotics can cause a widespread, non-allergic rash in individuals with Epstein-Barr virus infection. Physicians typically opt for alternative antibiotics, such as a macrolide like azithromycin, to treat the strep infection while avoiding this adverse reaction. Mono, a viral infection, does not have a cure, and its management focuses on supportive care, including rest, adequate fluid intake, and over-the-counter medications for fever and pain relief. Adhering to medical advice for both infections is important for recovery and to prevent complications.