Treating Strep Throat
When the distinction can't be made readily with an exam, physicians turn to an easy, five-minute strep detection test. These are antigen detection tests. The technology involves combining a part of the outer membrane of the strep bacteria with an antibody in the test solution. The chemical reaction results in a color change that shows up on the test strip as a positive result. When done correctly, this test is 75 to 85 percent accurate. Because a small percent of true infections can be missed, many doctors will treat a positive test, and send a back-up throat culture on the ones that are negative for more certainty. Culture results take 24 to 48 hours.
So why not treat all sore throats with an antibiotic, just to be sure? Studies have shown that of all the children who walk into a pediatrician's office with a sore throat, the majority will have a viral cause, and viruses don't respond to antibiotics. And there are dangers to exposing thousands of children to unnecessary antibiotics. A serious allergic reaction is one. Another is the potential for breeding stronger, resistant bacteria, an important and frightening issue in medicine today.
If left untreated, the symptoms of strep pharyngitis would self-resolve in two to five days. So, an equally fair question is why treat it at all? The answer to that was well worked out in studies done decades ago. There are four important reasons to treat:
- If treatment is begun early enough (within 24 hours), symptoms will resolve more quickly.
- Treatment reduces the contagiousness of the illness, thus the spread to others. Untreated, about one-third of those exposed to an ill person will develop strep. After 24 hours of an effective antibiotic, the risk of contagion is significantly reduced (which is why children are allowed back to school after one full day of treatment).
- Treatment reduces the chance that the illness will spread to other parts of the body.
- Finally, and arguably most importantly, there are serious and late complications to strep infections that can be prevented with a complete course of therapy. These complications result from an activated immune system triggered by the strep infection that then goes on to mistakenly attack innocent organs. Rheumatic heart disease is one example, as is a type of inflammation of the kidneys called glomerulonephritis, which can so damage the kidneys that they fail. Even starting antibiotics late in the course of a strep infection (including impetigo) helps prevent complications.
Fortunately, the treatment of strep pharyngitis is neither complicated nor expensive. A 10-day course of penicillin has been used for decades. Amoxicillin, known as the "pink medicine" to many families, is also a popular choice, as it tastes better. For those allergic to penicillins, there are other classes of antibiotics that are also effective. Strep infections won't be eliminated any time soon, but with accurate diagnosis and timely treatment we can aim to prevent the often devastating late complications seen with this illness.