Strep Throat

Sore throats cause illness in almost everyone during the winter and spring seasons. There are many causes including viral, allergic, reflux, and bacterial (strep and not strep). Streptococcus pyogenes (aka Group A Strep or “strep throat”) is the culprit 25% of the time.

With all the potential causes, how can you tell who has strep and who doesn’t? It’s not as easy as you think. There was a study that examined the accuracy of the clinician at predicting strep based on exam alone and the results were abysmal. Family practice, pediatricians, ENTs, infectious disease, etc – none of us were anywhere close to perfect. To improve our accuracy, we look at the clinical picture to determine consistent symptoms. In a perfect world, the patient has a scarlatiniform rash (slightly raised pink rash on their body), pus in their throat, bruising on their palate (roof of mouth), and large painful lymph nodes which improves accuracy to a whopping 50%. Unfortunately, patients rarely present like the textbooks tell us and there is huge variability of symptoms in different age groups. The criteria we are instructed to look for are swollen lymph nodes, pus in throat, fever, and lack of cough (except if under 3 years of age). If all of those findings are present, there is a 20% chance of strep. Terrible, right?

Fortunately, in office testing can be accomplished in about 8 minutes with an average 92% accuracy rate. If that test is positive, Bam! Here’s your antibiotic. For those that are negative, a throat culture should be sent off. This culture can find other strains of strep that are not Group A and has an accuracy rate of 97%. A culture consists of plating a throat swab in a nutritive agar to encourage growth. This is reassessed at 24 and 48 hours and if growth is noted, the bacteria is examined under a microscope to confirm. Empiric treatment for strep without a positive test is only recommended for those who have developed rheumatic fever or kidney problems in the past. A delay in treatment for everyone else does not increase the risk for complications. To be clear, waiting for the culture to be positive and then treating carries a lower risk of complications than treating unnecessarily with an antibiotic.

The most common reason we treat strep is to alleviate pain and fever and overwhelmingly, most people do great. However, strep infections should not be trifled with as they can lead to serious local infections including abscesses of upper airway, infection of the blood, and necrotizing infections (tissue death). They can also cause inflammatory responses in other organs such as glomerulonephritis (inflammation of kidney at microscopic level leading to failure), rheumatic fever (heart valve damage), and autoimmune neuropsychological syndrome in children called PANDAS.

The best news about strep infections is that there is very little resistance to antibiotics. Whatever is chosen works. How great is that? Amoxicillin is by far the most common treatment regimen which is generally well tolerated. The dosing was adjusted more recently for once-a-day dosing which is an added bonus. For penicillin-allergic people, cephalosporins (like Keflex), and azithromycin (think zpack) are options. Cephalosporins can cross react (cause similar reaction) with penicillin, so documentation of the specific penicillin reaction is key. The kicker for azithromycin is that a higher dose is required than the standard Zpack. Unfortunately, I have had to call in a second prescription more than once following dosing errors from local urgent care and emergency room settings. Clindamycin is also an effective drug, but I rarely use it because it is gross. The stomach side effects are significant, the dosing frequency is inconvenient and the liquid tastes vile.

Other important treatments are the acetaminophen (Tylenol) and ibuprofen (Motrin) for pain relief and fever control. Steroids have not been effective and are not recommended. Most adults and children turn around quickly in about 48 hours. Return to school can occur 24 hours after the first dose of antibiotics is completed as long as energetic enough and no fever.

Prevention is limited to handwashing and no shared drinks or utensils. I recommend replacing toothbrushes 24 hours after treatment started. This includes all toothbrushes that may come in contact with the infected person’s toothbrush as well.

Special topic of Recurrent Strep Infections: Most commonly due to incomplete adherence to medication (missed doses) or repeat infection from close contact who was not treated (household, daycare, school). I am often asked about tonsillectomy for treatment and this is our last treatment option. In order to qualify for surgery, there must be 7 documented cases in year, 5 documented cases per year for two years or 3 documented cases per year for three years. And then, even when surgery completed, the patient may still get strep.

Special topic of Strep carriers: There is a subset of the population that will test positive for strep and have no clinical disease. For whatever reason, their bodies will allow the bacteria to grow in upper respiratory system, but they don’t get infected. However, they can infect others. I see this occasionally when different members of the same household keep getting infected despite finishing their antibiotics appropriately. When I test the whole family, I will find it. Or sometimes I treat the entire family at the same time and the strep will disappear.

– On the bright side, you don’t have to wear a cone.