RESUMEN
OBJECTIVE: To investigate the clinical manifestations of infectious mononucleosis in children of different ages. METHODS: Clinical data from pediatric patients with infectious mononucleosis admitted from May 2015 to April 2019 were retrospectively analyzed. Patients were stratified into three groups (age 1-3 years, 4-6 years, and 7-14 years) for analysis of clinical and laboratory results. RESULTS: Data from 61 patients (male:female ratio 1.18:1) aged 5.15 ± 2.93 years (mean ± standard deviation; range: 1-14 years) were analyzed. Infectious mononucleosis occurred throughout the year and the main clinical manifestations were fever (98.3%), tonsillitis (100%), tonsillar white exudate (83.6%), cervical lymphadenopathy (98.3%), hepatomegaly (37.7%), splenomegaly (42.6%), eyelid edema (41.0%), and nasal obstruction (49.2%). Disease onset was most common during early childhood (37.7%) and at preschool age (37.7%). Younger children had more obvious symptoms of nasal obstruction and older children had more significant elevations of alanine aminotransferase and higher percentages of atypical lymphocytes. CONCLUSION: The clinical manifestations of infectious mononucleosis in children differed by age. These associations required attention for clinical decision making.