I returned to the exam room with the results of the five minute rapid strep test on an elementary school boy whose mom had brought him in with a complaint of a very sore throat. “His strep test is negative Mrs. Thompson.”
“Well that’s a relief!”
My own thoughts about it were a little more mixed. Most of the non-strep throat infections are viral so you are left to just letting them run their course.
Pharyngitis is the medical term for infection or inflammation of the throat, generally causing the symptom of a sore throat. The problem is, someone with a bad sore throat is usually hoping for antibiotics to help them get better. In fact up to 70% of patients going to a doctor for a sore throat (and there are about 15 million people in the U.S. who see the doctor for a sore throat every year) receive antibiotics. At the same time, only about 20 to 30 percent of children and just 5 to 15 percent of adults with a sore throat have strep. Most of the rest have viral infections where antibiotics only contribute to side effects and more resistant infections, while providing no benefit..
So how do we sort out which infections are strep and which are probably viral? First there are other symptoms that help greatly. If there is a runny nose or cough with the sore throat it is almost certainly viral and not strep. A classic strep throat has fever and sore throat without runny nose and congestion, but often with nausea or headache. Also, age matters: strep is uncommon under 3 years of age, peaks between 4-7 years of age, and becomes less common in adults, though still showing up sporadically.
It has been shown repeatedly that even experienced doctors can’t reliably tell a strep pharyngitis from a viral one just by looking – there is too much cross-over in how they appear. So a rapid strep test really is needed for accurate diagnosis. These are up to 90-95% accurate and only take a few minutes. Recently it has been recommended that the old routine of double-checking a negative rapid strep test with a throat culture be abandoned as it adds cost without any measurable additional benefit.
Here is a question that is not as obvious as it first appears: why do we even want to treat strep throats with antibiotics. It surprises most people to hear that strep throat will usually clear up in a few days (about 7 days on average) even without antibiotics. The benefits of the antibiotic (usually penicillin unless a person is allergic to it) are that they:
- Slightly shorten the course of the infection (by 12-16 hours)
- Render the person non-infectious more rapidly (usually within 24 hours of starting the antibiotic)
- May minimally reduce complications such as abscesses of the tonsils or ear infections
- May possibly help prevent serious other complications of strep pharyngitis. But this is controversial as they have never been proved to prevent the kidney disease called post-strep glomerulonephritis. Likewise many argue that rheumatic fever (a serious complication permanently damaging the heart) doesn’t seem to be caused by the vast majority of the strains of strep currently occurring in the U.S.
So the benefits of antibiotics for treating strep throat are sketchier than they were once thought to be. And on the other side of the coin, about 10% of those treated with antibiotics get diarrhea, occasionally a serious type caused by C. difficile. Also 0.24% have a life-threatening allergic reaction. This means that out of 10 million patients treated with antibiotics, as many as 24,000 of them will have fatal or near-fatal allergic reactions.
Most sore throats get better without treatment, even including strep pharyngitis. So the decision to test and treat is a bit more complicated than it was once thought and deserves some individual thought on a case-by-case basis. As a little side note, that’s why the emergence of telemedicine (where patience are diagnosed and treated by phone) holds as much concern as promise. The tendency to misdiagnose illnesses and misuse prescriptions will only grow with this looser connection between patient and physician.
So who thought something as “simple” as a sore throat would take two articles just to summarize? But we haven’t even mentioned mono or the non-strep bacterial culprits that can be other serious causes of your sore throat. More on that next time.