During the winter of 2014-2015, there were a number of children diagnosed with acute sialoadenitis or parotitis from the emergency department with presenting complaints of URI symptoms and sore throat. Initial work-up was aimed to rule out mumps, since in recent years several states have reported clusters of this particular viral infection. It was noticed that some patients had positive test results for influenza A establishing a possible association between influeza A and acute sialoadenitis/parotitis. Literature search yielded very few prior reports describing association between influenza A and acute parotitis in the pediatric population, with the most recent published cases reporting acute parotitis secondary to influenza H3/N2 subtype.
Institutional chart review revealed 12 cases of acute parotitis or sialoadenitis between October 2014 and January 2015. Due to the presence of URI symptoms and sore throat, 4 cases had additional diagnostic influenza testing. All samples were nasopharyngeal swabs collected for PCR testing performed by our hospital laboratory.
These 4 cases of influenza A included 2 males and 2 females, ages 10-20 years. The presenting symptoms consisted of: fever of 1-3 days duration in 3 patients, URI symptoms of less than 7 days, sore throat, and acute onset of bilateral swelling of the parotid or submandibular areas. On examination there were no signs of cellulitis, decreased neck mobility or upper airway inflammation. Mumps serologies were indicative of prior vaccination and other known viral causes of parotitis were ruled out (e.g.: EBV, CMV). Two of the confirmed 4 patients required hospitalization while pursuing workup, both of whom had CT images showing bilateral sialoadenitis as well as retropharyngeal fluid collections, prompting early empiric antibiotic therapy. All 4 patients had nasopharyngeal PCR test positive for influenza A, two of which had subtyping positive for A/H3. All 4 patients recovered without complications.
Acute parotitis or sialoadenitis during the winter months can be due to influenza A infection, even without the presence of systemic symptoms typical of influenza. In fully vaccinated children in whom mumps is ruled out, influenza virus infection should be included in the list of differential diagnoses of acute sialoadenitis.