Do Patients with Strep Throat Need to Be Treated with Antibiotics?

Background: Streptococcal pharyngitis is a common presentation to primary care and Emergency Department physicians. Every year, 10 million patients in the United States are treated with antibiotics for pharyngitis. However, less than 10% of these patients actually have strep pharyngitis (Barnett 2013). Prescribing of antibiotics for these patients centers on three arguments:

1. Antibiotics reduce symptomology
2. Antibiotics reduce the rate of suppurative complications
3. Antibiotics reduce the rate of non-suppurative complications (primarily Rheumatic Heart Disease).

So, do patients with strep throat need to be treated with antibiotics?

While treatment of strep throat seems relatively benign, there are significant harms that need to be considered:

1. 1 in 10 patients will develop antibiotic associated diarrhea (some of these will be C. diff)
2. Severe allergic reactions occur in 0.24% of patients

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.

Thus, it’s important to determine if the benefits of antibiotic treatment outweigh the risks.

Argument #1: Antibiotics reduce symptomology

The most important thing to recognize is that in the vast majority of patients, strep throat is a self limited disease that will get better in about 7 days with no treatment (this includes supportive care). The addition of antibiotics provides a modest benefit in terms of symptomology resolution (12-16 hours) (Del Mar 2006). This benefit, however, is in comparison to placebo, which is not standard care. Supportive therapies including acetaminophen and NSAIDs may affect symptom improvement but there are no good studies on this. Finally, we must not forget about the potential additional side effects associated with antibiotics (i.e. diarrhea).

One therapy that has shown remarkable benefits in terms of symptoms is the use of corticosteroids. Hayward et al showed that corticosteroids increased the rate of symptom resolution at 24 hours with an NNT = 4 (Hayward 2012).

Bottom Line: If we are interested in making the patient’s symptoms resolve faster, corticosteroids are our best bet. I typically give 10 mg of decadron IM.

Argument #2: Antibiotics reduce the rate of suppurative complications.

There are a number of potential complications associated with strep throat including acute otitis media (AOM), sinusitis and peritonsilar abscess (PTA).

	Yeh 2005	Del Mar 2006
AOM	NNT = 25	NNT > 200
Sinusitis	NNT = infinity	Not Reported
PTA	NNT = 28	NNT = 55 – 225

A more recent study demonstrated an overall suppurative complication rate of 1.3% and no difference in patients who received antibiotics versus those that did not (Little 2013).

Bottom Line: It appears that we would have to treat 100’s of patients to prevent one PTA; an easily treatable entity.

Argument #3: Antibiotics reduce the rate of non-suppurative complications.

The two major non-suppurative complications are: Post-strep Glomerulonephritis (PSGN) and rheumatic fever (RF). No study has ever shown that PSGN can be prevented and so, we are left with RF.

Evidence for preventing RF and subsequent rheumatic heart disease (RHD) comes from a series of studies performed in the 1950’s at the Warren Air Force Base. In this military population, investigators found that 2% of patients with strep throat developed RF. With antibiotics, this rate fell to 1% giving an absolute risk reduction of 1% and an NNT of 50-60 to prevent RF (Denny 1950, Wannamaker 1951, Chamovitz 1954, Siegel 1961). The work done by these researchers forms the basis for treatment over the last five decades.

However, we must ask the question of whether these studies apply to our patients today. The rate of RHD in the westernized world is exquisitely low. In fact, the CDC stopped tracking the incidence in 1995 when it fell below 1 per million. Numerous RCTs in

developed countries have shown no cases of RF or RHD in patients treated with placebo (Middleton 1988, De Meyere 1992, Dagnelie 1996, Little 1997, Zwart 2003).

Based on the current incidence of RF in the US, we would need to treat about 2 million patients with strep throat in order to prevent a single case of RF. In addition, only 1 out of every 3 patients who develops RF will subsequently develop RHD. Treating millions of patients with pharyngitis in the pursuit prevention of single digit cases of RHD in the western world makes no sense.

Many physicians argue that the reason for the decline in RF and RHD is because we treat every patient with pharyngitis for strep. However,epidemiologic data speaks against this. The incidence of streptococcal diseases fell long before the advent of antibiotics but fell concurrently with improvements in public health. It is a far more likely scenario that improvements in sanitation have led to shifts in the serotype of Group A beta-hemolytic streptococcus that causes strep throat in developed countries.

Clinical Bottom Line:

We are far more likely to harm patients with strep pharyngitis by giving antibiotics than to help them in developed countries. This does not apply to developing countries with poor public health (See this post from Casey Parker about treatment in developing areas).

Finally, let’s see what one of the core texts in EM has to say on the topic:

“acute pharyngitis should not typically be treated with antibiotics. The great majority of cases are viral in origin, and suppurative complications following streptococcal infection are both easily treated and too rare to justify routine use of antibiotics. In particular, antibiotics were beneficial in reducing rheumatic fever only during a single military epidemic in the mid-twentieth century, and the decline of rheumatic fever is unrelated to trends in antibiotic use.” (Rosen’s 2014)

Related Posts

• Newman D. Treatment of Acute Pharyngitis. SMART EM.
• Washington University EM: Antibiotics for Strep Pharyngitis – The Pediatric Perspective
• Edmund Kwok at CanadiEM: The (Real) Battle Against Strep Throat

Bibliography

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