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Streptococcus pyogenes infection, what is it? – Strep throat

Strep throat is a relatively common throat infection due to streptococcus pyogenes. The disease can have serious complications.

Everybody suffers from pharyngitis (sore throat) once in a while and some more often than others. Most of the time, sore throats are a consequence of benign viral infections that resolve spontaneously within five to seven days.

On the other hand, streptococcal pharyngitis (strep throat) is not the result of a viral infection but rather a bacterial infection with the streptococcus bacteria. Strep throat accounts for approximately 20 percent to 30 percent of all cases of pharyngitis.

In the United States, acute pharyngitis (bacterial or viral ) accounts for approximately 12 million ambulatory emergency department visits each year, making it one of the most common consult motives.

Strep infection is more frequent in children and adolescents between the ages of 5 to 15; however, the disease is not unheard of in adults. On average, an episode of bacterial pharyngitis in a child represents two days missed from school and two days missed from work for their parents.

As viral pharyngitis, strep infection resolves spontaneously in 4 to 5 days. However, antibiotic treatment can shorten the process by one or two days. Antibiotics also help prevent complications of the disease that will be further discussed in this article.

Is pharyngitis strep throat?

Pharyngitis is not the same as strep throat. All cases of strep throat are pharyngitis, but not all pharyngitis is strep throat. Pharyngitis simply refers to inflammation of the throat for any reason. Most pharyngitis cases have a viral origin, and only a minority of pharyngitis cases are strep throat.

Is strep throat contagious? 

Yes, strep throat is an infectious disease that is easily transmitted from person to person. Transmission usually occurs via respiratory droplets of nasal or oral secretions.

People with no symptoms (asymptomatic throat infection) due to streptococcus pyogenes is very likely to pass on the infection to those around them. You can get infected with strep throat if someone that has it coughs over you if you touch contaminated surfaces and rub your hands against your face or by sharing food and drinks with an infected person.

After getting infected, it may take two to five days before developing the first symptoms. However, you might be infectious for a few days, even before the development of symptoms.

What are the symptoms of strep throat?

Most symptoms of strep throat are also common to viral pharyngitis. Some of these symptoms include the following:

  1. A sore throat that can cause discomfort while eating or drinking
  2. Swollen tonsils
  3. Hoarseness 
  4. Headache
  5. Nausea
  6. Vomiting
  7. Abdominal pain
  8. Fever (more than 102 F or 38.3 C).
  9. Swollen lymph nodes in your neck 

The hallmark feature that helps to distinguish bacterial pharyngitis due to streptococcus pyogenes from viral pharyngitis or viral sore throat is the presence of white spots with or without streaks of pus in one tonsil or both and the back of your throat.

Some cases of strep throat also have little red spots on the roof of the mouth. Some patients might also develop a rash, known as scarlet fever. It is usually mild and does not represent a threat.

File:Scarlet fever 2.jpg
Scarlet Fever

Do you cough with strep?

Yes, it is possible to cough with strep throat, although it is more common for viral sore throat. Then, strep bacteria in your throat can come out in the respiratory droplets produced when you cough and are, therefore, infectious to other people.

How long does strep throat last?

Strep throat lasts for five days approximately without treatment; with treatment, recovery can occur within 2 to 3 days. Without antibiotic treatment, patients remain contagious weeks after symptoms disappear.

What are the complications of strep throat? 

Strep throat by itself is a relatively mild disease. However, untreated strep throat can lead to serious complications in some patients. These complications can be prevented by providing antibiotic treatment shortly after symptoms begin. 

There are two main kinds of strep throat complications

  1. Suppurative complications: The term refers to local complications in which the infection spreads from one site to another. Strep throat can evolve into otitis media, bacterial sinusitis, mouth abscesses, lymphadenitis, and mastoiditis. Mastoiditis is a serious infection that requires hospitalization and IV antibiotic treatment due to its potential of spreading to the brain.
  2. Non-suppurative complications: These complications are not the product of the infection itself but rather due to your immune system’s activation. Non-suppurative complications usually appear 2 to 4 weeks after strep throat symptoms disappear. The three major non-suppurative complications are rheumatic fever, rheumatic carditis, and post-streptococcal glomerulonephritis.

What is rheumatic fever? 

Rheumatic fever is an autoimmune inflammatory reaction that occurs 2 to 4 weeks after an episode of strep throat or other streptococcus pyogenes infections such as cellulitis or erysipelas. In rheumatic fever, your immune system mistakenly recognizes the body’s tissue proteins as streptococcus pyogenes antigens, thus leading to a destructive inflammatory response.

What are the symptoms of rheumatic fever?

Rheumatic fever attacks the joints, the heart, the central nervous system, the skin, and the soft tissue under it. Here is a list of the main symptoms.


It means joint inflammation. In rheumatic fever, arthritis is polyarticular and migratory. This means that it often attacks multiple joints but moves from one joint to another. It usually involves large joints, such as the knees, elbows, and ankles. In the majority of cases, joint inflammation resolves after 4 to 6 weeks without leaving any permanent damage.  

Erythema marginatum

It is a red, painless eruption that involves the upper part of the trunk; it is usually very mild and is only noticeable in fair-skinned individuals. The lesion can go on and off for weeks or months.

Sydenham chorea

It consists of jerky, uncontrollable movements of the face, hands, and feet. Episodes are usually sporadic, but in severe cases, they can be quite frequently. They can become a real problem for both the patient and its family. It usually starts 1 to 6 months after a strep throat episode; it can go on for months and even years.

Subcutaneous nodules

These are small, painless nodules or lumps underneath the skin, the patient rarely notices them, but an experienced physician can see them a physical medical exam.


It is the most serious complication of rheumatic fever due to streptococcal infection. Rheumatic carditis permanently damages the heart valves that separate the four heart chambers. This valve damage can lead to congestive heart failure, which is a life-threatening condition. Common symptoms include shortness of breath, swelling of the lower extremities, and chest pain. Sometimes the patient does not has any symptoms at first.

What is post-streptococcal glomerulonephritis?

In post-streptococcal glomerulonephritis, the immune complexes between antibodies and streptococcal antigens deposit in the renal glomerulus, causing inflammation and damage in that area. Kidney damage leads to a medical syndrome called nephritic syndrome. The nephritic syndrome has three main symptoms.

Blood in the urine (hematuria)

It can be either macroscopic hematuria, which is easily noticeable while urinating (the urine turns brown or reddish) or microscopic hematuria in which there isn’t enough blood in the urine to produce a color change. A urinalysis is the best method to diagnose microscopic hematuria.


The kidney is an important organ in arterial pressure regulation; damage to the glomerular apparatus will lead to a rise in blood pressure resulting in hypertension.

Water retention (edema)

When the kidney does not work properly, there is water and sodium retention that causes certain body parts to fill up with liquid, thus appearing puffy or swelled up. In nephritic syndrome, edema typically appears in the face, around the eyes. Although, it can also appear in the lower extremities. Facial edema tends to be prominent upon waking and subsides throughout the day.

Besides these three main symptoms, patients can also exhibit other symptoms such as weakness, malaise, abdominal pain, lack of appetite, nausea, and vomiting.

Post streptococcal glomerulonephritis appears 1 to 2 weeks after a throat infection and 3 to 4 weeks after a skin infection due to streptococcus pyogenes. 

How do doctors diagnose strep-throat?

Nowadays, many doctors use the Center score to distinguish bacterial pharyngitis from viral pharyngitis. The Center score is a checklist with four items.

  1. Fever
  2. Absence of cough
  3. Presence of pus in the tonsils
  4. Swollen neck nodes

The presence of each item adds one point to the score. Three or more points are diagnostic of bacterial pharyngitis and should prompt the physician to provide antibiotic treatment without hesitation. Two points should make your doctor request certain exams to determine the nature of the infections.

What tests are useful in strep throat?

Most of the time, strep throat diagnosis is clinical. This means that, in the majority of cases, physicians make the diagnosis and prescribe treatment based only on the signs and symptoms exhibited by the patient.

There are two main kinds of laboratory testing useful in strep throat: 

Rapid antigen detection tests; also called rapid strep test or rapid strep screen

It is a simple in-office test that detects the presence of streptococcus pyogenes. The doctor will ask you to open your mouth wide and press your tongue down with a wooden tongue depressor. It will then use a cotton swab to take a sample from the back of your throat (throat swab). Although this test is fairly reliable, the use of mouthwash and antibiotics can affect the results, leading to false negatives. Rapid antigen detection tests offer the advantage of providing immediate results.

Throat culture

This exam remains the gold standard for strep throat infection testing because it has a smaller error margin than rapid antigen detection tests. However, while rapid antigen detection tests offer immediate results, cultures take 48 to 72 to grow, which causes a delay in treatment. The sample taking procedure is very similar to the one in rapid antigen detection tests. Nowadays, throat cultures are only necessary when rapid antigen detection tests turn out negative in a patient with high suspicion of strep throat. 

Imaging studies such as CT scans are not useful in strep throat; however, they might help detect mastoiditis and abscesses complications.

How is strep throat treated?

Strep throat treatment has three main objectives: 

  1. Symptom relief 
  2. Decreasing the duration of symptoms
  3. Preventing complications 

Symptom relief is achieved with non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or diclofenac. Local, topical anesthetics like spray lidocaine can also help with throat pain for a few days. Strep throat usually lasts for five days; antibiotics can decrease symptom duration by one or two days. This is important because it decreases the amount of work or school days lost due to strep throat. 

The most important part probably is preventing complications; strep throat by itself is not a dangerous disease. It only causes mild to moderate discomfort for a few days. Hence, not a big deal.

Complications like mastoiditis, carditis, and glomerulonephritis are more serious and can even be life-threatening, so preventing them is of utmost importance. The only way to prevent these complications is by providing adequate and timely antibiotic treatment.

The gold standard antibiotic treatment for strep throat is intramuscular penicillin in a single dose. Other options include amoxicillin and azithromycin for patients that are allergic to penicillin.

Children and adults with strep throat should avoid work and school for at least 24 hours after beginning antibiotic treatment to avoid infecting others.

Does apple cider vinegar kill strep throat?

Although some non-scientific publications suggest that apple cider vinegar kills the bacterium responsible for bacterial pharyngitis, there is absolutely none scientific evidence behind this claim.

The only agents known to man that can kill a bacterium are antibiotics. And even if apple cider vinegar could provide some symptomatic relief, it certainly can not prevent any of the disease’s complications.

Do you think you have strep throat?

This is a Strep throat Symptoms checker. It gathers the most important signs, symptoms, and risk factors for this disease. Therefore, the tool will tell anybody who uses it if their symptoms are because of strep throat (Streptococcus pyogenes infection). Importantly, using this tool is free and would take a few minutes.

What do you think?

Written by Dr. Esteban Kosak

Doctor of Medicine - MD Recently Graduated from Medical School and inspired to aid the global population during this situation. I think that we shall no longer be waiting to see a doctor when we feel sick. Several times we feel disease searches in Google drive us to a rabbit hole and come out thinking that we may die of cancer or something very serious, given that symptoms may seem to fit a wide variety of illnesses. Since I recently graduated from medical school. I have all the medical information fresh in my mind. My thorough experience as an expert researcher allows me to very-well known the different diseases and conditions that affect human bodies. Empowered by the United Nations 17 Sustainable Development Goals (SGDs). I think that we all can provide a grain of sand to help humanity. That's why we created Symptoms.Care a place where you can come and screen your symptoms and find what different illnesses can be related to them. Armed with the right information you can instantly, discretely, secure and from the comfort of your home talk with a Doctor that can Evaluate your Symptoms and help you seek the right treatment.


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