By Cat Troiano
It’s that time of year. Schools, office buildings and other crowded public spaces are teeming with pathogens, from the common cold and influenza viruses to bacterial pneumonia and strep throat. Testing select patients who present with a sore throat provides the definitive diagnosis of strep throat so that effective treatment can be prescribed.
Sore Throat Is Not Always Strep Throat
The symptom of a sore throat can arise from irritants in the environment, inhalant allergies, acid reflux, postnasal drip, a fungal infection, a cold or a bacterial infection. A typical sore throat that often accompanies the onset of a cold is not the same as streptococcal pharyngitis, which is better known as strep throat. Strep throat is an infection caused by group A streptococci bacterium. A patient who has a cold-related sore throat typically experiences other upper respiratory symptoms as well, such as coughing, nasal congestion, chest congestion and a runny nose. These symptoms do not accompany strep throat. Symptoms that do commonly go hand in hand with strep throat include the following:
- High fever, typically 101 degrees Fahrenheit or greater
- Redness of the throat and on the hard and/or soft palate
- Dark red spots in the mouth, on the palate or on the throat
- White or yellow patches on the tonsils
- Swollen tonsils
- Swollen lymph nodes in the neck
- Pain or difficulty when swallowing
- Loss of appetite
- Muscle aches
- Sandpaper-like skin rash that is pink in color
Children and teens aged 5 to 15 are the most typically affected, with nearly 30 percent of patients of this age group presenting with sore throats being diagnosed cases of strep throat, compared to only an average of 10 percent of adults with sore throats. Kids are taught to share, and they aren’t shy about sharing germs! However, adults who are frequently exposed to children, such as day care workers and schoolteachers, as well as parents of children who have the infection, are also at risk. Strep throat is contagious, and the incubation period is two to five days post exposure. Strep infection is rare in children less than three years of age.
Any patient who presents with a sore throat that began quickly and persists for a week, or with a sore throat combined with a fever along with any of the additional symptoms that may be indicative of strep throat, should be tested so that proper treatment can be initiated.
Swab for Strep
There are two ways to test for group A streptococci. One test, the rapid streptococci screening test, yields results quickly. This immunoassay test identifies the presence of group A streptococci antigen in a sample of mucous that has been taken from a pharyngeal swab, and it generates a positive or negative result in approximately 5 to 10 minutes. A positive result can facilitate confident on-site diagnosis and prompt initiation of effective treatment.
The second way to test for strep is the traditional microbial culture method. Like the rapid strep test, the culture test requires a sample that has been swabbed from the back of the throat. Although culturing a sample has a high level of accuracy due to high sensitivity and specificity, the test can take 48 hours to generate results. Since a culture can generate more accurate results than the rapid strep testing, this method is recommended to confirm negative rapid strep test results from symptomatic patients as well as to rule out other infections. In addition to group A streptococci, the throat culture test also detects the presence of pathogens that cause such conditions as bacterial pneumonia, meningitis and pertussis.
It is important to note that patient use of antiseptic mouthwash products as well as recent antibiotic therapy can alter the results of rapid strep tests and throat culture tests.
Some patients may be carriers of group A streptococci, which simply means that such individuals may harbor the bacteria without having an active infection. Carriers will have positive results on their tests, even if their sore throats are caused by other pathogens. Patients who are otherwise asymptomatic and test positive for strep throat typically do not require treatment, as carriers are much less likely to develop complications that can arise from failure to treat strep infections, and their probability of spreading the bacteria to others is lower.
Treatment and Prevention
While sore throats that present with viral infections, which do not respond to antibiotic drugs, typically resolve without treatment, it is essential to treat strep throat promptly. Failure to treat a strep infection places the patient at risk for serious complications. One such complication is rheumatic fever, a life-threatening inflammatory condition that affects the joints and can also ultimately result in congestive heart failure. Another potential complication is poststreptococcal glomerulonephritis, which is an inflammation of the glomeruli – the filtration structures of the kidneys – that can lead to kidney disease and renal failure. Other complications include ear infections, sinus infections, abscesses on the tonsils, scarlet fever and mastoiditis, which is an inflammation of the mastoid process, which is the lower portion of the temporal bone of the skull.
Once the rapid strep test issues a positive result, antibiotic therapy is prescribed for a period of 5 to 14 days, depending on which antibiotic drug is used. Patients should stay home from school or work until at least 24 hours after the antibiotic treatment has begun and the fever is gone. It is imperative that patients complete the entire prescribed course of antibiotic treatment, even once symptoms improve, in order to ensure that the infection is completely resolved. Antibiotic treatment will prevent the aforementioned complications that can arise from an untreated strep infection, decrease the symptoms, shorten the duration of illness and reduce the spread of infection to others.
Group A streptococci is spread through contact with droplets from infected patients who sneeze or cough. When someone touches a contaminated surface and proceeds to touch his or her eyes, nose or mouth, he or she can contract the infection. Patients should cover their mouth with a tissue if they sneeze, and everyone should refrain from sharing drinking glasses, cups and bottles as well as dining utensils. Everyone should also be extra diligent with washing their hands frequently throughout the school year, which also tends to coincide with the flu season.
Since some of the symptoms of strep throat and those of the influenza virus are similar, a rapid influenza test may be ordered along with the rapid strep test for a more thorough and definitive diagnosis. Testing is a crucial part of ensuring a proper diagnosis so that ineffective treatments can be avoided and the development of patient antibiotic resistances can thus be prevented.