Strep throat is a common bacterial infection that targets the throat and tonsils. It is caused by the bacterium Streptococcus pyogenes, also known as Group A Streptococcus (GAS). While it often presents with familiar symptoms, relying on self-diagnosis is unreliable and potentially risky.
Key Physical Symptoms of Strep
Strep throat typically begins suddenly with a sore throat that makes swallowing painful. This discomfort is frequently accompanied by a fever, often 101°F (38.3°C) or higher.
Upon visual inspection, the throat and tonsils may appear intensely red and swollen. A specific sign of strep is tonsillar exudate, which manifests as white patches, streaks, or spots of pus covering the tonsils. Small, pinpoint red spots, termed petechiae, can sometimes be observed on the soft or hard palate.
Swelling and tenderness of the lymph nodes in the front of the neck, known as anterior cervical adenopathy, is another localized finding. Other symptoms, particularly in children, can include headache, nausea, and stomach pain.
Distinguishing Strep from Viral Sore Throats
Differentiating a bacterial strep infection from a common viral sore throat is a significant challenge because many symptoms overlap. However, the presence of typical cold symptoms strongly suggests a viral cause, not strep. Strep throat is typically characterized by the absence of a cough, a runny nose, or hoarseness.
Clinical tools, such as a simplified version of the Centor criteria, estimate the probability of a bacterial infection before testing. This system assigns points for factors like fever, the presence of tonsillar exudate, and the absence of a cough.
High-risk factors for strep include younger age, specifically being between five and fifteen years old, as strep is less common in toddlers and adults. When clinical findings suggest a high probability, they guide healthcare providers to proceed immediately with diagnostic testing.
The Process of Medical Confirmation
A physical examination alone cannot confirm a strep infection, making laboratory testing a necessary step for definitive diagnosis. The initial test performed is usually the Rapid Strep Test (RST), also known as a Rapid Antigen Detection Test (RADT). This test involves swabbing the back of the throat to collect a sample, with results available within minutes.
The RST is valued for its speed, allowing immediate treatment if positive. A positive result is highly specific, accurately confirming the presence of Group A Streptococcus bacteria. However, the RST has lower sensitivity, risking a false negative result.
Because of this risk, especially in children, a negative RST is often followed up with a throat culture. The throat culture is considered the gold standard for diagnosis because it allows the bacteria to grow in a lab, providing a more accurate result. While the culture requires a wait of 24 to 48 hours for final confirmation, this two-step testing process balances the need for rapid treatment with the demand for diagnostic accuracy.
Necessary Treatment and Risks of Ignoring Strep
Once a strep infection is confirmed, treatment involves a course of antibiotics, typically penicillin or amoxicillin. Antibiotics are necessary to eliminate the Streptococcus pyogenes bacteria and alleviate symptoms, which usually begin to improve within one or two days of starting the medication. It is important to complete the entire course of antibiotics prescribed by the provider, even if symptoms disappear quickly.
Stopping treatment prematurely allows some bacteria to survive, risking a relapse of the infection and potentially leading to antibiotic resistance. The reason for prompt and complete antibiotic treatment is the prevention of severe, long-term complications. These issues are caused by the body’s immune response to the untreated infection, not the bacteria directly.
The two main complications are acute rheumatic fever (ARF) and post-streptococcal glomerulonephritis (PSGN). ARF is an inflammatory condition that can affect the heart, joints, brain, and skin, often resulting in heart valve damage. PSGN is an inflammation of the kidneys that can develop one to three weeks after the initial infection. Treating strep throat with antibiotics within nine days of symptom onset specifically prevents the onset of acute rheumatic fever.