Strep throat is most common in children between the ages of 5 and 15, although it can happen in younger children and adults. Children younger than 3 can get strep infections, but these usually don't affect the throat. Strep throat is most common in the late fall, winter, and early spring. The infection is spread by person-to-person contact with nasal secretions or saliva, often among family or household members. People with strep throat get sick 2–5 days after they are exposed. The illness usually begins suddenly, with a fever that peaks on the second day. Many also have sore throat, headache, stomachache, nausea, or chills. In some people, strep throat is very mild, with only a few of these symptoms. In others, strep throat is severe. There are many strains of strep. Some strains produce toxins that can lead to a scarlet fever rash. This rash is thought to be an allergic reaction to the toxins. Untreated, strep throat can sometimes lead to rheumatic fever. Kidney complications are among the other possibilities.
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