Overview of Strep Throat
Strep throat (also called Streptococcal pharyngitis) is inflammation of the throat resulting from a bacterial infection. Strep throat is common in school-aged children. Onset usually is sudden and the condition often is diagnosed based on clinical symptoms and a positive throat culture for Streptococcus bacteria.
There are two types of Streptococcus bacteria: group A and group B. Group A Streptococci (GAS) is more common. This type causes strep throat, as well as skin infections (e.g., impetigo, cellulitis), scarlet fever, and toxic shock syndrome. Group B Streptococci can cause bacterial pneumonia, meningitis (infection of the membranes that surround the brain and spinal cord), and blood infections.
Incidence and Prevalence of Strep Throat
In most cases, sore throat (pharyngitis) occurs as a result of a viral infection. About 15 percent of sore throats are caused by Streptococcus bacteria.
Strep throat is most common between the ages of 5 and 15. The condition also can occur in younger children and adults. In children younger than 3 years of age, strep infection often causes ear infection (otitis media) and usually does not result in a sore throat.
In the United States, children typically average one Streptococcus infection every 4 years. Strep is most prevalent in late fall, winter, and early spring, when children are in schools and daycare centers.