Strep throat is a common, highly contagious bacterial infection caused by Group A Streptococcus bacteria. It is responsible for only a portion of all sore throats, as viruses are the more frequent cause. While symptoms offer strong clues, self-assessment cannot replace medical testing for a definitive diagnosis.
The Primary Indicators of Strep Throat
The symptoms of strep throat typically appear suddenly and with intensity, often without the gradual onset of a common cold. A hallmark sign is a sore throat that can be severe, making swallowing painful and difficult. This pain is usually accompanied by a quick rise in body temperature, with fever often reaching 101°F (38.3°C) or higher.
Upon visual inspection, the tonsils and the back of the throat often appear red and swollen. A telling sign is the presence of white patches, streaks of pus, or inflamed red spots on the tonsils. Tiny red spots, called petechiae, may also be visible on the soft or hard palate, which is the roof of the mouth.
The body’s immune response to the bacteria causes the lymph nodes in the neck to swell and become tender to the touch. Children may also experience additional symptoms like nausea, vomiting, or abdominal pain, which are less common in adults. The suddenness and specific visual signs are key differentiators from other causes of a sore throat.
Symptoms That Suggest a Viral Cause
Most sore throats are caused by viruses, which do not require antibiotic treatment. If a sore throat is accompanied by symptoms of an upper respiratory infection, it is likely to be viral, such as a common cold or the flu. The presence of a cough, a runny nose, or nasal congestion strongly suggests a viral infection rather than strep throat.
Other signs that point toward a viral origin include hoarseness or changes in the voice. The presence of conjunctivitis (pink eye) alongside a sore throat is a strong indicator of a viral infection. These additional symptoms are rarely present in a case of strep throat.
Viral sore throats will not respond to antibiotics and typically improve on their own within a week. Recognizing these viral indicators helps prevent unnecessary antibiotic use, which is ineffective against viruses and can contribute to antibiotic resistance.
The Medical Diagnosis Process
Because symptoms alone cannot reliably distinguish between a bacterial and viral infection, a definitive diagnosis requires a medical professional. The process begins with a physical examination and a discussion of symptoms, followed by a throat swab to test for the Group A Streptococcus bacteria. This quick procedure involves gently rubbing a sterile swab over the back of the throat and tonsils.
The sample collected is then used for a diagnostic test, most commonly a Rapid Strep Test (RST). The RST can detect the bacterial antigens within minutes, allowing for immediate treatment if the result is positive. However, the RST has a lower sensitivity, meaning it can sometimes produce a false negative, particularly in children.
If the RST is negative but the clinical suspicion remains high, especially in children, the medical provider may send the swab for a throat culture. This process involves allowing the sample to grow in a laboratory setting for 24 to 48 hours. The throat culture is considered the gold standard for accuracy and ensures that an infection is not missed.
Necessary Treatment and Follow-Up Care
If a strep throat diagnosis is confirmed, treatment with a full course of antibiotics is mandatory. Antibiotics like penicillin or amoxicillin are typically prescribed to reduce the duration and severity of the symptoms. Starting the medication within 48 hours of illness onset can significantly improve recovery time.
The primary reason for treatment is to prevent rare but serious non-suppurative complications that can arise from an untreated strep infection. These complications include rheumatic fever, which can lead to permanent damage to the heart valves, and post-streptococcal glomerulonephritis, a form of kidney inflammation. Completing the entire course of antibiotics is non-negotiable.
A person is generally considered no longer contagious and can return to work or school after 24 hours of starting the antibiotic and once the fever has resolved. Stopping the medication early, even if symptoms have disappeared, risks a recurrence of the infection and increases the danger of developing one of the severe complications.