From the Guidelines
Post-streptococcal conditions can be effectively prevented with prompt antibiotic treatment, and penicillin is the recommended first-line treatment for patients with confirmed strep throat, as it is cost-effective and has long-standing proven efficacy, as stated in the 2009 American Heart Association guidelines 1. The most serious post-streptococcal conditions include acute rheumatic fever and post-streptococcal glomerulonephritis.
- For patients with confirmed strep throat, prompt antibiotic treatment with penicillin (typically penicillin V 500 mg twice daily for 10 days in adults or amoxicillin 50 mg/kg once daily for 10 days in children) is recommended to prevent these complications.
- For penicillin-allergic patients, alternatives include clindamycin or macrolides like azithromycin, as suggested by the 2012 Infectious Diseases Society of America guidelines 1.
- Complete the full antibiotic course even if symptoms improve quickly. After a streptococcal infection, monitor for signs of complications such as:
- Joint pain
- Skin rash
- Unusual movements
- Decreased urination with dark or foamy urine These complications typically develop 1-3 weeks after the initial infection. Patients with rheumatic fever may require long-term antibiotic prophylaxis to prevent recurrence, while post-streptococcal glomerulonephritis usually resolves on its own but requires monitoring, as noted in the 2009 American Heart Association guidelines 1. The immune response to streptococcal bacteria can cross-react with human tissues, particularly heart valves, joints, and kidney tissues, causing inflammation and damage in these organs. It is essential to follow the guidelines for the diagnosis and management of group A streptococcal pharyngitis, as outlined in the 2012 Infectious Diseases Society of America guidelines 1 and the 2002 Infectious Diseases Society of America practice guidelines 1, to prevent acute rheumatic fever, suppurative complications, and minimize potential adverse effects of inappropriate antimicrobial therapy.
From the FDA Drug Label
In three double-blind controlled studies, conducted in the United States, azithromycin (12 mg/kg once a day for 5 days) was compared to penicillin V (250 mg three times a day for 10 days) in the treatment of pharyngitis due to documented Group A β-hemolytic streptococci (GABHS or S. pyogenes) Azithromycin was clinically and microbiologically statistically superior to penicillin at Day 14 and Day 30 with the following clinical success (i.e., cure and improvement) and bacteriologic efficacy rates (for the combined evaluable patient with documented GABHS): Three U. S. Streptococcal Pharyngitis Studies Azithromycin vs. Penicillin V EFFICACY RESULTS Day 14Day 30 Bacteriologic Eradication: Azithromycin323/340 (95%)255/330 (77%) Penicillin V242/332 (73%)206/325 (63%) Clinical Success (Cure plus improvement): Azithromycin336/343 (98%)310/330 (94%) Penicillin V284/338 (84%)241/325 (74%)
Post-streptococcal treatment with azithromycin is effective, with a bacteriologic eradication rate of 95% at Day 14 and 77% at Day 30, and a clinical success rate of 98% at Day 14 and 94% at Day 30 2.
From the Research
Post-Streptococcal Complications
- Post-streptococcal complications can occur after a streptococcal infection, including acute rheumatic fever, post-streptococcal reactive arthritis, pediatric autoimmune neuropsychiatric disorders, and post-streptococcal glomerulonephritis 3.
- These complications can be prevented through primary prophylaxis, which involves limiting the circulation of the etiologic agent, and secondary prophylaxis, which aims to prevent streptococcal re-infections in subjects who have already developed complications 4.
Clinical Presentation
- Post-streptococcal reactive arthritis (PSRA) is characterized by inflammatory arthritis of ≥1 joint associated with a recent group A streptococcal infection, and can cause acute asymmetrical non-migratory polyarthritis, tenosynovitis, and small joint arthritis 5.
- PSRA can be associated with extraarticular manifestations, including erythema nodosum, uveitis, and glomerulonephritis, and tends to occur within 10 days of a group A streptococcal infection 5.
- Post-streptococcal glomerulonephritis (PSGN) can present with asymptomatic microscopic hematuria to gross hematuria, edema, hypertension, proteinuria, and elevated serum creatinine levels 3.
Diagnosis and Treatment
- The diagnosis of post-streptococcal complications requires evidence of recent streptococcal infection, and can be confirmed through antistreptolysin O titers and other antibody markers 6.
- Treatment of PSRA usually involves nonsteroidal anti-inflammatory drugs (NSAIDs) or corticosteroids, and most cases resolve spontaneously within a few weeks, but some cases can be recurrent or prolonged 5.
- Rheumatic fever is a rare condition that requires two major or one major and two minor Jones criteria for diagnosis, and treatment involves NSAIDs, corticosteroids, and echocardiography to identify patients with subclinical carditis 3.