You can stop Googling this one: No one knows for sure why certain children get recurrent strep throat. If your child comes down with more than five infections in a year, you should talk to your doctor about it.
At the same time, it’s worth asking yourself: “Is this actually strep throat?” Only 20 to 30 percent of childhood sore throats are caused by Streptococcus bacteria. The rest result from viral infections like colds and mononucleosis, allergic rhinitis, and gastroesophageal-reflux disease.
However, strep is the only one of these conditions that requires antibiotics, since untreated strep throat could potentially lead to rheumatic fever, a condition that can damage a child’s heart valves. (Some experts say that in extremely rare cases, strep may also cause a serious illness known as PANDAS.)
No one can look at your child’s throat and tell you that she has strep; the only way to know is to obtain a throat swab. Providers first do a rapid strep test, which takes about six minutes and finds 90 percent of strep infections. A negative test should be followed up by a throat culture, which usually takes 48 hours.
Even strep tests can be misleading, though. About one in eight children are “carriers” of strep throat, meaning that the bacteria are hanging out in their tonsils but not making them sick. These kids will almost always test positive. In order to avoid overtreating strep, providers should be selective about whom they test. Children under age 3 and over age 15 rarely need strep tests, since they almost never develop rheumatic fever. The same goes for kids with obviously viral symptoms like mouth ulcers or a cough without a fever.
Source: https://www.parents.com/