Only about to of VRS episodes are complicated by bacterial infection. 48 Although ABRS is often considered a transition from a preceding viral URI, bacterial infection can develop at any time during the course of illness. The concept of a transition, however, is useful for management decisions, especially when considering the time course of VRS and which disease patterns are most likely to be associated with bacterial infection. In the first 3 to 4 days of illness VRS cannot be differ- entiated from an early-onset ABRS, and for that reason only patients with unusually severe presentations or extrasinus manifestations of infection are presumed to have a bacterial illness. Similarly, between 5 and 10.
