What is Streptococcal Pharyngitis?
Acute pharyngitis, or sudden inflammation of the throat, is a common reason people visit the doctor. Around 12 million visits each year, or 1 to 2% of all visits to out-of-hospital care centers, are due to this condition. It’s particularly common among children and adolescents, who make up 50% of these visits. Despite the high number of visits, most cases of pharyngitis are caused by viruses and get better on their own. However, a type of bacteria called Group A Streptococcus (GAS) is the most common bacterial cause of acute pharyngitis. GAS is responsible for 5 to 15% of adult cases and 20 to 30% of cases in children.
What Causes Streptococcal Pharyngitis?
Streptococcus pyogenes, also referred to as Group A Streptococcus (GAS), is a type of bacterium. This bacterium can live and grow either by itself or within our bodies. It is a ‘gram-positive coccus,’ which means it’s a round-shaped bacterium that stains dark purple in a common lab test because of the structure of its cell wall. In addition, it grows in chain-like formations.
Risk Factors and Frequency for Streptococcal Pharyngitis
Group A Streptococcus, often abbreviated as GAS, is the most frequently occurring bacterial cause of sore throats in children and teenagers. Its peak occurrence is during the winter and early spring. Children of school age or those who are in close contact with school-aged children are the most likely to contract GAS pharyngitis. A recent study showed that 37% of patients under 18 years old who visited an outpatient clinic for a sore throat were diagnosed with GAS pharyngitis. For children younger than 5, this figure was 24%. For adults, GAS pharyngitis usually appears before the age of 40 and then steadily declines.
Signs and Symptoms of Streptococcal Pharyngitis
Research has indicated that a doctor cannot reliably diagnose GAS pharyngitis using just a patient’s medical history and a physical examination. However, certain signs can suggest the condition. These include a sudden sore throat, a high fever, no cough, and being around someone who had GAS pharyngitis within the past two weeks. During a physical exam, a doctor may note swollen lymph nodes in the neck, signs of inflammation in the throat, fluid buildup on the tonsils, small red spots on the roof of the mouth (palatine petechiae), and swelling of the small, finger-shaped piece of tissue hanging from the soft palate (uvular edema).
- Sudden sore throat
- High fever
- No cough
- Exposure to someone with GAS pharyngitis
- Swollen neck lymph nodes
- Inflammation in the throat
- Fluid on the tonsils
- Small red spots on the roof of the mouth
- Swelling of the uvula
Testing for Streptococcal Pharyngitis
The Centor criteria is a tool that doctors use to decide who should be tested and treated when Strep throat (GAS pharyngitis) is suspected. However, the Infectious Disease Society of America (IDSA) states that it’s tough to diagnose strep throat based solely on a patient’s medical history and physical symptoms, because these indicators are similar to a variety of other illnesses, both infectious and non-infectious.
This similarity of symptoms, coupled with the difficulty in differentiating strep throat from other causes, means that the IDSA recommends bacterial testing in all cases, except when a clear viral infection is expected. Children younger than 3 don’t usually need this testing because both strep throat and acute rheumatic fever are uncommon in this age group. However, if children under 3 are at risk—like, for example, if they have siblings with strep throat—doctors might consider testing them.
When testing is needed, the IDSA advises using a rapid antigen detection test (RADT), as a first step to help diagnose strep throat. If this test is positive, a throat culture generally isn’t necessary, because the RADT is usually quite accurate. For children, if the RADT is negative, a throat culture should follow, but this isn’t usually necessary for adults due to the low rates of strep throat and acute rheumatic fever in this age group.
Testing for anti-streptococcal antibodies, which are produced by the body in response to a previous strep infection, doesn’t help in diagnosing a current case of strep throat because it only shows past infections. After treatment, retesting to ensure the infection has cleared isn’t typically necessary, but can be considered in special cases.
Treatment Options for Streptococcal Pharyngitis
The main goals of treating strep throat (GAS pharyngitis) are to lessen the length and severity of a patient’s symptoms, prevent immediate and delayed complications, and stop the spread of infection to others.
Penicillin or amoxicillin is the recommended treatment for those with strep throat, as these antibiotics are relatively inexpensive and have fewer side effects. For patients who are allergic to penicillin, other antibiotics like clindamycin, clarithromycin, azithromycin, or a type of cephalosporin can be given.
To manage pain and fever associated with strep throat, additional therapies like acetaminophen or a type of anti-inflammatory drug, called an NSAID, are recommended by the Infectious Diseases Society of America (IDSA). However, they don’t recommend the routine use of corticosteroids, another type of anti-inflammatory drug.
After starting antibiotic treatment, patients usually start feeling better within one to three days and can return to work or school after 24 hours of treatment. Re-testing is not typically required after treatment unless a patient has history of severe complications from strep throat, like rheumatic fever. Preventative antibiotics are also not typically recommended unless a patient has a history of severe complications, or if repeated infections are occurring within a family or close contacts. Stopping the spread of the disease can be achieved through proper hand hygiene.
What else can Streptococcal Pharyngitis be?
There are numerous reasons why someone might get sick, and it’s important to know that not all of them are due to infections. In fact, some can be non-infectious. Here are some possible infectious and non-infectious causes:
The infectious causes could be due to:
- Respiratory viruses such as parainfluenza, rhinovirus, coxsackievirus, adenovirus, and others
- Arcanobaceterium haemolyticum
- Different species of mycoplasma
- Different species of chlamydia
- Corynebacterium diphtheria
- Acute HIV infection
- Neisseria gonorrhoeae bacteria
- Treponema pallidum bacteria
- The Epstein-Barr virus
- Fusobacterium necrophorum bacteria
On the other hand, some non-infectious causes could include:
- Allergies
- Gastroesophageal reflux disease, a condition where stomach acids back up into the esophagus
- Exposure to second-hand smoke
- Physical trauma
- Autoimmune disorders, such as Behçet syndrome and Kawasaki disease
- A foreign object in the body
Possible Complications When Diagnosed with Streptococcal Pharyngitis
Suppurative and non-suppurative complications can develop from group A streptococcal (GAS) pharyngitis. Suppurative complications are those where pus is formed. These can include conditions like throat and tonsil inflammation or abscess, ear infection, sinus infection, a serious skin infection known as necrotizing fasciitis, blood infection, meningitis, brain abscess, and infection of the jugular vein.
On the other hand, non-suppurative complications do not form pus but can also lead to a variety of health issues. These include acute rheumatic fever, reaction arthritis after a streptococcal infection, scarlet fever, a severe illness known as streptococcal toxic shock syndrome, kidney inflammation, and a disorder in children associated with group A strep infection that affects the brain, known as PANDAS.
Complications of GAS Pharyngitis:
- Suppurative Complications:
- Throat and tonsil inflammation or abscess
- Ear infection
- Sinus infection
- Skin infection (necrotizing fasciitis)
- Blood infection
- Meningitis
- Brain abscess
- Jugular vein infection
- Non-Suppurative Complications:
- Acute rheumatic fever
- Post-streptococcal reaction arthritis
- Scarlet fever
- Severe illness (streptococcal toxic shock syndrome)
- Kidney inflammation
- Pediatric disorder affecting the brain (PANDAS)
