If strep throat is suspected as the cause of tonsillitis in your child, your doctor will do a throat swab to confirm that there is infection with strep bacteria. A rapid antigen test is usually performed in the office. If this test is negative, there is still a small chance that your child has strep and an overnight culture will then be done to see if any strep bacteria grow. It is important to remember that you can not tell the difference between strep throat and other viral causes of sore throats. Just because there is pus on your child's tonsils, it does not mean that he needs an antibiotic. Antibiotics are only used to treat sore throats that are caused by strep, so if the tests are negative, your child most likely has a virus that will need to clear up on its own.
This infection is easily treated with antibiotics, usually penicillin or amoxicillin (which are now usually prescribed just twice a day). Your child will no longer be contagious after being on an antibiotic for twenty four hours. It is important to take a complete course of antibiotics to prevent your child from getting rheumatic fever.
The bacteria that causes strep throat is very sensitive to antibiotics, so if your child gets another infection quickly after having strep throat it is more likely that he has a new infection. Because strep is thought to survive on tooth brushes, you should consider replacing your child's tooth brush after a strep infection, especially if he keeps getting infected.
About ten to twenty percent of people are carriers for strep, meaning that the bacteria lives in the back of their throat without causing infection. And although the strep isn't causing any problems, if you test someone who is a carrier, the test will be positive. The best way to avoid being overtreated with antibiotics when you are a carrier is to avoid being tested when your child doesn't have classic symptoms of strep throat. Your doctor may also decide to use a stronger antibiotic as treatment so that your child isn't a carrier anymore, although this is probably not necessary for most children.
My child was diagnosed with strep throat and is on penicillin but isn't getting better. How come?
It isn't really known why some kids with strep do not get better with antibiotics, since it is believed that the strep bacteria are very sensitive to penicillin. One possibility, and probably the most common reason, is that your child does not have strep at all. Many viruses can cause symptoms that are identical to strep, and unless he was tested for strep and confirmed to have strep throat, then he may just have a virus which would not be expected to respond to antibiotics. Even if he did test positive for strep, it is possible that he is just a carrier for strep and has a virus causing his symptoms.
Many bacteria now produce enzymes called beta-lactamase that can inactivate penicillin and amoxicillin. These bacteria become resistant to these antibiotics. Fortunately strep is not able to produce these enzymes and no resistant strep has yet been found. It is possible though that your child has other bacteria in his throat that do produce this enzyme (copathogen hypothesis) and inactivate the penicillin before it has a chance to work. In this case, a stronger antibiotic that works even if the beta-lactamase enzyme is around may be useful.
Strep itself can become resistant to other antibiotics, especially trimethoprim sulfamethoxazole (Bactrim), erythomycin (although this is often used in children that are allergic to penicillin) and azithromycin (Zithromax).
For children with recurrent strep, it may be helpful to delay treatment until a child has had symptoms for a few days. Some studies show a better response to antibiotics if treatment with penicillin is delayed until at least 48 hours after symptoms begin. This isn't practical in a lot of cases though, because delaying treatment would also delay when he could go back to school, since he would be contagious longer.
Can't we just give him a shot of antibiotics?
Although a penicillin shot given once was long the standard of treatment for strep throat, is mostly used now in children with strep and persistent vomiting, so that they are unable to keep down an oral antibiotic.
Does he need his tonsils out?
Tonsillectomies used to be done much more commonly than they are now. The current indications for tonsillectomy for recurrent strep throat is having five or more episodes of strep throat in a year, or having four episodes each year for two years in a row. Tonsils are more commonly removed to relieve symptoms of obstructive sleep apnea.