Streptococcus pyogenes (beta-hemolytic group A streptococcus) represents the most common bacterial cause of tonsillopharyngitis that necessitates antibiotic therapy. Regardless of its widespread prevalence, the ideal approach to disease management still remains a matter of debate.
In a majority of cases, streptococcal pharyngitis represents a self-limited illness, even if no antimicrobial therapy is administered. The primary goal of treatment is the prevention of acute rheumatic fever, but benefits also include alleviation of symptoms, shortening the duration of the disease, limiting household spread, and averting suppurative complications.
Penicillin as a drug of choice
The value of penicillin in the management of strep throat was already established in the late 1940s and early 1950s, and it remained the treatment of choice to this day. The main reasons are uniform susceptibility of Streptococcus pyogenes strains to this beta-lactam antibiotic and its effectiveness in both primary and secondary prevention of acute rheumatic fever.
The Infectious Diseases Society of America (IDSA), the American Heart Association (AHA), the American Academy of Family Physicians (AAFP) and the World Health Organization (WHO) endorse either a single intramuscular injection (benzathine penicillin G) or a 10-day course of oral treatment (phenoxymethyl penicillin or penicillin V) as a first-line approach.
If the therapy is initiated within the first 48 hours of illness, a prompt resolution of fever ensues and the spread of Streptococcus pyogenes is contained (therefore children can return to school). Failure to respond clinically should cast doubt on the accuracy of the diagnosis.
An adjunctive therapy with anti-inflammatory drugs such as ibuprofen and diclofenac, or analgesic agents such as paracetamol can help in reducing severe symptoms and control high fever. Nevertheless, it should be emphasized that acetylsalicylic acid (Aspirin) should not be used in children in order to avoid rare, but potentially fatal Reye’s syndrome.
Alternative treatment options
Sometimes penicillin is substituted with oral amoxicillin suspension due to its better taste, which is also available in the form of chewable tablets. Standard regimen is a 10-day course, three times per day (although there is some evidence that once per day regimen is of comparable effectiveness).
In patients with penicillin allergy (and without immediate-type hypersensitivity to beta-lactam antibiotics), first-generation oral cephalosporins are acceptable alternatives. Still, there is an increased usage of more expensive, broad-spectrum cephalosporins of second and third generation without clinical justification.
The penicillin-allergic individuals may be treated with erythromycin, azithromycin or clarithromycin. However, approximately one third of patients do not complete treatment with erythromycin due to drug-induced adverse reactions. Furthermore, extensive use of these antimicrobial drugs can result in community-wide increase of erythromycin-resistant beta-hemolytic group A streptococcus.
Certain studies suggest that azithromycin administered at a dose of 60 mg per kilogram of body weight in children or given for 3 days at a dose of 500 mg per day in adults may be more effective than other treatment schemes in eradicating and curing streptococcal tonsillopharyngitis. There is also a factor of improved compliance to the treatment.
In conclusion, albeit several antimicrobial drugs appear to be effective in eradicating Streptococcus pyogenes present in the throat, the current recommendation is still a 10-day course of penicillin, or erythromycin for patients that are allergic to penicillin.