Severe infectious mononucleosis in immunocompetent adults.

Objectives: To determine the risk factors for severe infectious mononucleosis (IM) occurrence in immunocompetent adults.

Methods: We performed a multicenter, retrospective case series including immunocompetent adults presenting with confirmed IM between 2001 and 2011. Severe presentations were compared with uncomplicated presentations using Stata 9 software. The significance level was set at 5%.

Results: In univariate analysis, age over 30 years (n=13 or 41.9% vs. n=5 or 12.8%; P=0.006), prior use of non-steroidal anti-inflammatory drugs (NSAIDs) (n=7 or 87.5% vs. n=1 or 12.5%; P=0.009), and smoking (n=13 or 68.4% vs. n=6 or 31.6%; P=0.013) were associated with severe IM onset. In multivariate analysis, only age over 30 years (OR=3.55; P=0.05) and prior use of NSAIDs (OR=15; P=0.05) remained associated with severe IM onset, without reaching significance level (P=0.05).

Conclusion: Our study confirmed that age over 30 years is a risk factor for severe IM onset. Prior use of NSAIDs also seems to be correlated with severe presentations. This new data needs to be confirmed in a prospective study.