As the leading cause of physician office visits and loss of time from school as well as the cause of significant morbidity among young children, respiratory infections impose a major burden on the health care system. The most common causative pathogens are Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis. In young children acute otitis media and sinusitis may present with relatively nonspecific symptoms such as irritability. Older children may complain of more specific problems; for example those with otitis media may complain of otalgia. Upper respiratory tract infections are typically diagnosed by signs and symptoms and treated empirically with an antimicrobial agent that offers coverage of the usual causative respiratory pathogens.