BACKGROUND: Peripheral facial paralysis is a clinical presentation which, in most cases, is benign. It is relatively frequent, although less so in pediatric patients, where clinical diagnosis is more difficult. This clinical condition can be congenital, neurological, infectious, neoplastic, traumatic, or metabolic in origin.

CASE REPORT: This report describes the case of a male infant of 23 months of age with peripheral facial paralysis due to Epstein-Barr virus (EBV) upper respiratory infection. A hemogram showed the presence of leukocytosis and lymphocytosis, and a peripheral blood smear indicated the presence of stimulated lymphocytes. Serological tests were compatible with recent EBV infection: IgM anti-VCA (capsid antigen) was positive, while IgG anti-VCA and anti-EBNA (nuclear antigen) were negative. EBV genome was detected in pharyngeal swab and in serum, where viral load was 5.08 log copies/1000 cells and 3.72 log copies/mL, respectively.

CONCLUSIONS: Whilst the most common cause of facial paralysis is idiopathic paralysis, such problems of the facial nerve may have many origins, including an infectious nature such as infection with viral agents. Rapid determination of the etiology of the problem allows the most appropriate management of the condition and quick follow-up to be implemented, which is essential for the evaluation of treatment response and the avoidance of permanent consequences.

Keywords: Epstein-Barr Virus Infections, Facial Paralysis, Infant, Respiratory Tract Infections, Viral Load