Strep throat is a bacterial infection of the throat and tonsils caused by Group A Streptococcus (GABHS). For a confirmed case of strep throat, antibiotics are almost always necessary. While antibiotics shorten the duration of symptoms, the treatment is fundamentally preventative. The main goal of antibiotic therapy is to eradicate the bacteria completely to prevent rare but serious long-term complications.
Confirming the Diagnosis
The decision to use antibiotics relies entirely on a confirmed diagnosis, as most sore throats are caused by viruses that do not respond to this medication. Clinical judgment alone cannot distinguish between viral pharyngitis and a bacterial strep infection. Therefore, testing is mandatory before a prescription is written to ensure the correct use of antibiotics and avoid unnecessary risks.
The most common diagnostic tool is the Rapid Strep Test (RST), which provides results in minutes by detecting the streptococcal antigen. The RST is highly specific, meaning a positive result indicates a true infection, allowing immediate antibiotic treatment. However, the RST has lower sensitivity and can sometimes produce a false-negative result, meaning the bacteria are present but undetected.
Because of the potential for false-negatives, a negative RST result in a child often requires confirmation with a throat culture or Polymerase Chain Reaction (PCR) test. The throat culture is considered the gold standard because it allows bacteria to grow in a lab, providing a more accurate result, though it takes 24 to 48 hours. In adults, a negative RST does not routinely require a follow-up culture, as the risk of serious complications is significantly lower.
Preventing Severe Complications
The most compelling reason for antibiotic treatment is the prevention of non-suppurative sequelae, which are delayed complications not related to pus formation. These serious conditions are autoimmune reactions triggered by the body’s response to the streptococcal bacteria. Antibiotics eliminate the GABHS bacteria entirely, interrupting the chain of events that leads to these severe reactions.
The most concerning complication is Acute Rheumatic Fever (ARF), a condition that can affect the heart, joints, brain, and skin. The immune system mistakenly attacks its own tissues, particularly the heart valves, which can lead to permanent damage known as Rheumatic Heart Disease (RHD). Timely antibiotic treatment, ideally within nine days of the infection’s onset, can prevent ARF entirely.
Another potential complication is Post-Streptococcal Glomerulonephritis (PSGN), which causes inflammation of the small filtering units in the kidneys. While the link between antibiotic treatment and the prevention of PSGN is less clear than for ARF, treatment is still given to eradicate the bacteria and prevent the spread of nephritogenic strains. Treatment with antibiotics has significantly reduced the incidence of these conditions, especially ARF, in developed countries.
Adherence to the Treatment Protocol
Once a diagnosis is confirmed, the effectiveness of the treatment hinges on adherence to the full prescribed course of medication. The standard treatment is typically a 10-day course of penicillin or amoxicillin, which are the drugs of choice due to their effectiveness and safety profile against GABHS. It is necessary to complete the entire 10-day regimen, even if symptoms such as sore throat and fever resolve quickly, often within 24 to 48 hours of starting the medication.
Stopping the medication prematurely risks leaving behind bacteria that could regrow, potentially leading to a recurrence of the infection. More importantly, it risks failing to fully prevent ARF. Completing the full course ensures the complete eradication of the bacteria from the throat, which is necessary to prevent the immune response that triggers severe complications.
For individuals with a known penicillin allergy, alternative antibiotics are available, such as a narrow-spectrum cephalosporin or clindamycin. The duration of the course may vary, but the instruction to complete the full regimen remains the same. Adhering to the treatment protocol ensures the infection is cured, minimizes the risk of spreading the bacteria to others, and secures the preventive benefits against severe, long-term health issues.