Know the symptoms. A sore throat (especially while swallowing), white spots, and enlarged lymph nodes are the hallmarks of strep, but some kids may also -- or even only -- have a fever, headaches, body aches, abdominal pain, nausea, or vomiting. Scarlet fever (a strain of strep) shows up as a red, sandpapery rash on the neck and upper torso. If your child also has a cough, congestion, and hoarseness, it's probably a virus -- not strep throat.
Get your child tested. If you suspect strep, it's time for a throat culture. The newer rapid swab test delivers a result in minutes. If your doc uses the slow test, wait for the results before starting medication unless the symptoms are textbook; antibiotics won't cure a virus -- the culprit in the vast majority of sore throats -- and overuse can lead to resistance.
Use the right treatment. Most effective: penicillin drugs (including Amoxicillin and Ampicillin), since some strep strains are resistant to the newer erythromycin drugs. Your child will no longer be contagious a day after her first dose, and she'll feel better in 24 to 48 hours.