As a symptom of the common cold, sore throats are familiar to everyone. Sometimes you even wake up with a sore throat after sleeping in a dry room or a night out in a smoky bar. Occasionally, people, most commonly children, suffer from strep throat, which is a bacterial infection treated with antibiotics.
Between 1989 and 1999, 70 percent of adults who went to the doctor for a sore throat received an antibiotic prescription. While it’s believed this prescription rate is declining, experts say that people are still receiving antibiotics unnecessarily. This may be because it is hard to tell who has the infection without doing a test or because people just want to walk out of the office with a prescription so they can feel better. The inappropriate use of antibiotics not only fails to ease sore throat symptoms, it contributes to the growing problem of antibiotic resistance. However, it is still important to identify people who have strep because, if untreated, this infection can lead to serious consequences such as rheumatic fever.
Warren McIsaac, MD, associate professor of family medicine, family and community medicine at University of Toronto, led a study published in the april 7 2004 issue of The Journal of the American Medical Association that examined different guidelines for the use of throat cultures for bacterial infections. The authors reviewed data from 787 children and adults who went for a sore throat to a family medicine clinic in Calgary, Alberta. “What we concluded was that there are a number of different strategies, depending on the physician’s setting, that were appropriate in that they would allow you to reduce unnecessary antibiotic use,” he explains. Below, Dr. McIsaac discusses when throat cultures and antibiotics are needed.
What causes sore throat?
It is estimated that 80 percent of sore throats are caused by viruses, and 10 to 20 percent are caused by Streptococcus bacteria. Of course, there are some other causes you’ve got to keep in mind; especially in adolescents, such as infectious mononucleosis. Out of all the cases of sore throat that come through a physicians office, the challenge for a physician lies in trying to pick out that 10 to 20 percent of people with sore throats that are really strep—who need antibiotics.
How are sore throats caused by viruses different than those caused by bacteria?
That’s a big part of the problem. There often isn’t a difference in symptoms. The vast majority of people who have a viral infection or strep throat may have any combination of sore throat, runny nose, swollen glands, cough and fever. So it’s very difficult to differentiate whether it’s a virus or strep throat simply by examining people.
There are some people with classic symptoms of strep, such as a very severe sore throat with pus on the tonsils, swollen tonsils and swollen glands. It turns out this is a small group, maybe only 10 or 15 percent of people with strep are going to have those types of symptoms.
In people with scarlet fever, strep throat is accompanied with a very typical type of rash; it’s often described as a sandpaper-like rash, on the trunk of the body, particularly in the underarm and groin areas.
How do you test for strep throat?
Traditionally, a throat culture or rapid strep test is recommended. Both are done by swabbing the tonsils and the back of your throat. In a throat culture, the organism is grown out in the laboratory to positively identify that there is a strep organism present in a person’s throat. So that’s been the traditional gold standard method of identifying or confirming that this sore throat is caused by strep and not a virus.
A positive rapid strep test is generally also considered proof of a strep infection. The important difference is the rapid antigen test takes anywhere from 10 to 30 minutes to be processed in a doctor’s office, whereas a throat culture takes anywhere from 24 to 48 hours to be processed in a standard laboratory.
However, most experts recommend that children still have a throat culture if the rapid test is negative because the rapid test will sometimes miss cases of strep.
What are the consequences of not treating strep?
What’s not widely known is that the main reason that strep throat is treated with antibiotics is to prevent a complication called rheumatic fever. We don’t see much of this anymore because strep throat is usually treated with antibiotics. Between the turn of the century and about 1950, there was a lot of rheumatic fever. Rheumatic fever is a disease that comes on about 2 weeks after a strep throat infection. It can develop into rheumatic heart disease where there is damage to the heart valves, which may require heart surgery to replace those valves later in life.
How long should someone wait before they go to the doctor to get tested?
We did a study a few years ago where we showed about 80 percent of people don’t go to the doctor when they’ve got a viral sore throat or a respiratory infection. They make a pretty good distinction: “This is probably a cold.” And when their uncertainty level gets too high, they’re going to the doctor for advice, which is really quite appropriate. There are a couple cases when you should visit your physician. We know that strep is more common in kids between the ages 5 to 11 years. A sore throat with a fever and/or skin rash may indicate scarlet fever and needs to be seen by a doctor.
If you have a mild sore throat with a runny nose, cough, perhaps with some muscle aches, and no fever, you can generally wait a few days to see if the symptoms get better.
What is the downside of using antibiotics for viral infections?
Antibiotics work against bacteria and not viruses. And using antibiotics for viral infections increases levels of antibiotic resistance. It seems clear that, when you take the antibiotics for your viral sore throat, there are other bacteria present in your body that become resistant to antibiotics.
What is your advice to someone with a sore throat or someone who has a child with one?
If you’re uncertain about whether or not you need medical attention, that’s a good time to see a doctor and get some advice. If you go to your doctor and they recommend not taking antibiotics, it’s most likely because it’s a virus, and again, it’s important not to take the antibiotics to minimize the chance that we’re going to have greater problems with antibiotic resistance.
If an antibiotic is prescribed, you need to make sure you complete the course of the antibiotics because we know that not taking a full course of antibiotic therapy can also contribute to making bacteria more resistant.
I would suggest entering into a partnership with your personal physician, and have each person play their part in making sure that we’re using antibiotics responsibly to limit resistance and ensure we have effective antibiotics for years to come.