What is Bacterial Pharyngitis (Strep Throat (Pharyngitis))?
Pharyngitis, often referred to as a sore throat, is the result of the back part of the throat becoming inflamed or irritated. While many instances stem from non-infectious or non-bacteria related causes, bacterial infections do make up a significant number of throat infections. These infections display different symptoms, can lead to different complications, and need specific treatments.
Being able to accurately identify a bacterial throat infection and knowing when to check for less common causes is a crucial skill for any healthcare provider. This knowledge can help prevent unnecessary treatments and health complications that can result from overlooked or improperly treated infections.
What Causes Bacterial Pharyngitis (Strep Throat (Pharyngitis))?
Acute pharyngitis, or a sore throat, is a common condition that affects both kids and adults. It is often caused by non-infectious factors, like seasonal allergies or acid reflux, or by viruses. However, if bacteria are behind it, the main culprit is usually the group A beta-hemolytic streptococcus, more commonly known as strep throat. This type of bacteria is spread through the air or by swallowing it, and it can lead to various immediate or delayed health problems.
Other types of bacteria, such as groups C and G streptococcus, can also cause pharyngitis. However, because it is often hard to tell whether these bacteria are just present in the throat or are actually causing an infection, it’s difficult to figure out how often they are to blame. Some sexually transmitted infections, like Neisseria gonorrhea and Chlamydia trachomatis, may cause pharyngitis if certain risk factors are present, although they usually do not cause symptoms. In very rare cases, pharyngitis can be caused by other types of bacteria, like Yersinia pestis and Corynebacterium diphtheriae, particularly if there’s a chance the person was recently exposed to them in specific regions.
Risk Factors and Frequency for Bacterial Pharyngitis (Strep Throat (Pharyngitis))
Sore throat is a very common reason why people visit doctors’ offices, emergency rooms, and urgent care centers. Sore throats particularly affect children, who make up about half of all cases. Adults can also have sore throats, but bacterial sore throats are less common in adults over 40.
- Most bacterial sore throats are caused by Group A strep infections, particularly in children.
- Children are more likely to experience acute and delayed complications from these infections.
Other bacteria can cause sore throats too, but these are less common and usually associated with certain risk factors. For example,
- Gonorrhea and chlamydia can cause sore throats, but often there are no symptoms; about 10% of people with certain risk factors might have a throat infection caused by a sexually transmitted infection.
- Diphtheria, another potential cause, is usually only found in people who haven’t been vaccinated, or in parts of the world where the disease is still common.
Signs and Symptoms of Bacterial Pharyngitis (Strep Throat (Pharyngitis))
Bacterial pharyngitis, a type of sore throat, is typically rapid in development and might come with other symptoms, like a red rash or stomach pain. In order to diagnose and treat this condition, healthcare providers need to understand the patient’s full symptom history, timeline, any previous episodes, and potential risk factors. Symptoms associated with upper respiratory issues, like stuffy nose, cough or eye irritation are usually linked to viral infections or seasonal allergies. Recurrent or continuous symptoms without fever are often allergy-related. Factors like high-risk sexual activity or close contacts with strep throat can signify a greater likelihood of the condition.
During a physical check-up, the provider will check for fever and other signs of illness. They’ll examine the ears, eyes, and nose for causes of any existing symptoms or explanations for fever. They’ll also look at throat and neck to see if there’s any swelling or discharge of the tonsils and throat, and to check for swollen lymph nodes. These signs usually indicate a bacterial cause. More spread out swelling of the eyes, nose, and throat might suggest non-bacterial causes. In children particularly, the presence of a rough, red rash could indicate scarlet fever, and other skin eruptions could suggest different infections.
- Rapid development of severe sore throat
- Red rash or stomach pain (sometimes)
- Upper respiratory symptoms, such as stuffy nose, cough, or eye irritation (suggestive of viral infections or allergies)
- Recurrent or persistent symptoms without fever (suggestive of allergies)
- High-risk sexual activity or contact with strep throat (increases likelihood of bacterial pharyngitis)
- Fever and other signs of illness
- Swelling or discharge of the tonsils and throat
- Swollen lymph nodes
- Widespread swelling of the eyes, nose, and throat (suggestive of non-bacterial causes)
- Presence of rough, red rash in children (could indicate scarlet fever)
Testing for Bacterial Pharyngitis (Strep Throat (Pharyngitis))
Diagnosing bacterial throat infections, or pharyngitis, should not just be based on a doctor’s physical exam. It should involve a mix of thorough checking by the doctor, combined with appropriate lab tests. To avoid guess work during the doctor’s check-up, several tools have been created. In addition, a range of quick and lab tests are available that confirm if the symptoms are due to bacterial infection.
One evaluation method is the Centor criteria, which was created to assess the likelihood of a bacterial throat infection. These criteria check for things like throat sores, a fever over 100.4 F (38 C), swollen neck lymph nodes, and the absence of a cough. If a patient scores low on these criteria (0-1), it’s unlikely that they have a bacterial infection and testing may not be necessary. Patients scoring high on these criteria (3-4) are more likely to have the infection and should have further testing. The McIsaac criteria adjusts the Centor criteria to consider different age groups, and the FeverPAIN criteria includes factors like the severity of inflammation, and the lack of cough or cold-like symptoms.
A rapid antigen detection test (RADT) can be used to quickly check for bacterial infections. It’s a specific test with about a 95% accuracy, meaning if it’s positive, no other testing is required. But its sensitivity varies between 70 – 90%, so if a patient shows strong signs of bacterial infection, a negative RADT result should be verified with a traditional throat culture.
A bacterial throat culture is the best method for diagnosing a bacterial throat infection, but the problem is that the results may take a day or two. Nucleic acid amplification tests (NAAT) are very sensitive, and are endorsed by the CDC for checking conditions like sore throat, even though they’re not approved by the FDA. Certain blood tests may also be used to evaluate possibilities of a systemic illness.
Imaging may only be necessary in situations where the patient shows signs of severe conditions like an abscess, in which case, they should be moved to an emergency or inpatient department.
It’s important to note that even if a patient meets all criteria for the evaluation tools, they have only a 50-65% chance of actually having a bacterial throat infection. Therefore, it’s recommended not to solely rely on clinical evaluations to decide on a treatment plan. Confirming infections before treatment can help avoid unnecessary use of antibiotics.
Treatment Options for Bacterial Pharyngitis (Strep Throat (Pharyngitis))
If you have bacterial pharyngitis, which is a throat infection, it is necessary to treat it with the right antibiotics after confirming the infection. Along with the antibiotics, over-the-counter medications like nonsteroidal anti-inflammatory drugs or acetaminophen may be used to help with fever and pain.
For a specific type of throat infection called GABHS, doctors usually recommend penicillins like Penicillin V and Amoxicillin. These are the first choice because they’re effective, low-cost, and the bacteria have not shown any significant resistance to them. If you’re mildly allergic to penicillin or it isn’t available, Cephalosporin antibiotics are a good alternative. However, it’s recommended to use the narrowest possible spectrum of this drug to avoid building resistance to it. For those with more serious allergies to penicillin, Azithromycin can be used. Still, it’s important to note that some bacteria have developed resistance to this antibiotic. If resistance to Azithromycin is known, Clindamycin can be used, but do keep in mind that some people have a hard time tolerating this drug due to its taste and potential side effects like stomach problems and the risk of other bacterial infections.
In the case of gonorrhea or chlamydia in the throat, the treatment is the same as that used for genital infections. This typically involves a combination of two antibiotics, 250 mg ceftriaxone given through injection and 1000 mg of azithromycin taken orally.
If you’re diagnosed with diphtheria, you should immediately report it to the CDC. The best treatment includes antibiotics like erythromycin or penicillin and an antitoxin, which you can get from the CDC. It’s essential to isolate the patient until two consecutive tests taken 24 hours apart show no presence of the bacteria.
For infections caused by Yersinia pestis bacteria, the most effective treatment is with antibiotics like aminoglycosides or tetracyclines. Patients should also be kept in isolation until tests indicate they are no longer contagious and have received antibiotics for at least 48 hours.
If the throat infection leads to complications, such as an abscess around the tonsils, this should be managed in a hospital where all the necessary resources are available for surgical intervention or other specialized treatments, especially if the patient’s breathing becomes compromised.
What else can Bacterial Pharyngitis (Strep Throat (Pharyngitis)) be?
In many cases, acute bacterial throat infections are either not caused by bacteria or are not infectious. However, when doctors consider the chance of a bacterial throat infection, they should also think about other possible causes such as:
- Allergic reactions due to things like pollen, pollution, inside and outside, or drugs
- Throat irritation from stomach acid reflux or smoking
- Trauma to the throat caused by excessive shouting, snoring, or recent use of a breathing tube
- Mouth ulcers
- Viral throat infections from common cold or flu viruses like adenovirus, rhinovirus, or coronavirus
- Viral throat infection from more severe viruses like those causing mononucleosis, pandemic coronavirus or HIV
- Fungal infections such as yeast infection in the esophagus
- Possible bacterial complications like an infection of the lymph vessels or abscesses around the tonsils or behind the throat.
What to expect with Bacterial Pharyngitis (Strep Throat (Pharyngitis))
Acute bacterial pharyngitis, or a bacterial throat infection, usually gets better on its own. If the infection is confirmed and treated with the right antibiotic, patients usually recover well. However, in rare cases, some complications may occur.
There are instances when patients might get the infection again within a month after antibiotic treatment. This happen if they didn’t take their medication properly or if they were exposed to the bacteria again. In such cases, they can be given a different antibiotic, often one with a wider range of bacterial coverage. Doctors will emphasize the need for sticking to the medication regimen and avoiding risk factors. Antimicrobial medicines like amoxicillin-clavulanic acid, clindamycin, and intramuscular penicillin G are regularly used. If the infection happened after the use of a certain type of antibiotic (first-generation cephalosporin), the medical practitioners might increase the medication to a more stronger type (third-generation cephalosporin).
Throat infections that are sexually transmitted are usually easy to treat and often don’t cause symptoms.
Two rare throat infections, diphtheria and Yersinia pestis, typically respond well to treatment, provided medical resources are available. However, they might be serious in areas with limited resources. In regions where diphtheria is prevalent, the disease can have a death rate between 3-20%, often due to a heart complication or limited access to healthcare. Likewise, Yersinia pestis has a death rate of less than 15% when treated, and it can soar to 60 to 100% if left untreated.
Possible Complications When Diagnosed with Bacterial Pharyngitis (Strep Throat (Pharyngitis))
Bacterial pharyngitis, or a throat infection, can lead to various complications, depending on the specific bacteria causing it. Generally, the bacterial infection can spread and cause other health problems. This includes:
- Abscess, or a pocket of pus in tissue
- Cellulitis, a skin infection
- Lymphadenitis, or swollen lymph nodes
- Meningitis, an infection of the fluid around the brain and spinal cord
- Bacteremia, or bacteria present in the bloodstream
Additionally, local swelling from the infection may trigger inflammation and blockages, leading to sinusitis and ear infections.
While strep throat is usually not severe and can improve on its own, it is important to treat it promptly with antibiotics. This is because strep throat can sometimes lead to severe complications. For example, the bacteria can release toxins that cause scarlet fever or a severe infection known as toxic shock syndrome. An immune response to a strep throat infection can also lead to acute rheumatic fever, a disease that can affect the heart, joints, brain, and skin. However, post-streptococcal glomerulonephritis, a type of kidney disease that can occur after a strep throat infection, cannot be prevented through antibiotic treatment.
Throat infections caused by sexually transmitted infections, such as gonorrhea and chlamydia, often do not cause symptoms. However, these infections are contagious and can cause symptoms and complications in sexual partners. For instance, these complications include pelvic inflammatory disease in women, inflammation of the testicles in men, and inflammation of the prostate in men.
The main issue with diphtheria is due to the toxins it produces. These toxins can cause tissue death and inflammation, leading to problems such as breathing difficulties due to swelling in the upper airway, heart problems due to inflammation of the heart muscle, and paralysis through nerve damage.
Pharyngitis, or throat inflammation, caused by the Yersinia pestis bacteria, does not typically present as an initial symptom. However, the bacteria can progress to cause severe lymphadenitis, or swelling of the lymph nodes, and then potentially spread throughout the body.
Preventing Bacterial Pharyngitis (Strep Throat (Pharyngitis))
You can prevent bacterial pharyngitis, which is a type of throat infection, by following good hygiene practices. These include washing your hands regularly, not sharing food or drinks, and covering your mouth when you sneeze. It’s also crucial to fully complete any prescribed course of antibiotics. By taking your antibiotics as instructed, you can help the treatment work better, stop the infection from coming back, and prevent the bacteria from becoming resistant to the medicine.
