Strep Throat – Causes, Signs and symptoms

Strep Throat

Summary

Strep throat is an infection of the throat caused by group A streptococci bacteria. These bacteria can cause inflammation and infection in a variety of areas throughout the body, including the respiratory system, skin and vital organs. In addition, damage to the heart valves (in rheumatic fever) and kidneys (glomerulonephritis) sometimes occurs.

A strep throat infection can be transmitted by kissing, coughing or sneezing. Symptoms usually appear within five days of exposure to the bacteria and include a sore throat, fever, swollen neck glands and inflamed tonsils. Symptoms tend to begin suddenly and are usually more severe than those experienced with viral infections. Coughing and a runny nose are not signs of strep throat.

Most cases of strep throat occur in children between the ages of 5 and 15. People who spend time in crowded environments (e.g., work, daycare facilities, school) or who live in northern areas of the United States face an increased risk of developing strep throat.

People who suspect they have strep throat are urged to consult a physician. A physical examination and medical history may be performed, although the only way to identify the presence of strep throat is with a throat culture and/or rapid strep test. The rapid stress test is similar to a throat culture, but with much faster results.

Antibiotics are used to treat strep throat. This kills the bacteria that causes infection, limits the spread of infection to others and prevents serious medical conditions that may occur if an untreated infection spreads throughout the body. People remain contagious for at least a day after beginning treatment. It may be impossible to completely avoid people carrying the bacteria that cause strep throat. Some people may carry the bacteria but never develop an infection themselves and will not display any symptoms. Among the best ways to prevent infection is to practice good hygiene (e.g., hand-washing with soap and water). Replacing a toothbrush after infection is a good way to prevent the recurrence of infection.

About strep throat

Strep throat is a contagious bacterial infection that causes inflammation within the throat. It affects the pharynx (back of the throat) and tonsils (two oval-shaped tissue masses located inside the mouth, at either side of the throat). Sometimes, the adenoid (tissue mass located behind the nose in the upper throat) may also become swollen and infected. Left untreated, strep throat can damage the heart valves (in rheumatic fever) and kidneys (glomerulonephritis).

The bacteria that cause strep throat are from a class of bacteria called group A streptococci (strep), also known as Streptococcus pyogenes or group A beta-hemolytic streptococcus. Most often, a person develops strep throat after exposure to a person already infected with the bacteria. Other times, the bacteria can live harmlessly in the nose or throat for some time without causing infection, and can then be triggered by stress or immune system dysfunction, resulting in infection. 

Strep throat occurs most often in children between 5 years and 15 years old, although it may affect people of all ages. Approximately 15 percent of sore throats in children are due to strep throat, according to the American Academy of Family Physicians.

There are many different strains of strep bacteria, which can cause a number of different types of illnesses. Thus, even though people develop antibodies to the particular form of strep with which they were infected, they remain vulnerable to other strains. For this reason, people are often diagnosed with strep throat multiple times.

In addition to strep throat, strep bacteria can cause inflammation and infection in other areas of the body, such as:

  • Ear, nose and throat problems. These include tonsillitis, sinusitis and otitis media. In some cases, these infections may accompany strep throat. The strep bacteria can also cause bacterial pneumonia.
  • Skin infections. The strep bacteria can infect the skin, causing impetigo, cellulitis and erysipelas (inflammation in upper layers of the skin). The U.S. Centers for Disease Control and Prevention (CDC) estimates that over 10 million cases of strep-caused skin and throat infections occur every year. In some people, cellulitis infection may develop in the rectum (streptococcal perianal cellulitis) or vagina (streptococcal vaginitis).
  • Scarlet fever. Infectious disease that may occur following a strep throat infection. It can cause a bright red rash, sore throat and fever.
  • Severe, invasive infections. These include bacteremia (infection that enters the bloodstream), streptococcal toxic shock syndrome (causes blood pressure to drop and vital organs to fail) and necrotizing fasciitis (flesh-eating disease). These infections can be fatal. An estimated 9,000 invasive infections occur annually in the United States, according to the CDC.

Risk factors and causes of strep throat

Strep throat is caused by group A beta-hemolytic streptococci bacteria (also known as streptococcus pyogenes). A person develops strep throat after coming into contact with the bacteria in the saliva or nasal discharge of an infected person. This can occur during kissing, sneezing or coughing. It is unlikely that a person will contract strep from touching contaminated surfaces and then touching one’s own mouth, nose or eyes.

When strep throat recurs after treatment within a household, a carrier (person who carries the bacteria but displays no symptoms of infection) may be the cause. Occasionally, the strep bacteria may not have been entirely eliminated from a person’s body, even after antibiotic treatment. However, carriers are much less contagious than people with symptoms.

Factors that may increase a person’s risk of strep throat include:

  • Age. Children between the ages of 5 and 15 years are at highest risk for strep throat. Strep throat rarely occurs in infants and toddlers.
  • Crowded environments. Anyone spending time in crowded environments, such as work, school, playgrounds and daycare facilities is at an increased risk of catching infectious diseases, such as strep throat.
  • Spring, fall months. Strep throat occurs most often during the spring and fall months.
  • Poor hygiene. Anyone who fails to practice good hygiene (e.g., hand-washing with soap and water) is at an increased risk of developing bacterial infections, such as strep throat.
  • Northern regions. Strep infections are more common in the northern areas of the United States, rather than in the southern areas.

Signs and symptoms of strep throat

Signs and symptoms of strep throat usually appear within five days of being exposed to the bacteria that cause the condition. The first sign of strep throat is often a sore throat. Although sore throat can also indicate a viral infection, a sore throat associated with strep tends to last longer than in the case of a cold or the flu. In addition, symptoms of strep throat are generally more severe and begin more suddenly than viral infections of the throat.

Common symptoms of strep throat in people age 4 years and older include:

  • Sudden, high fever (higher than 102 degrees Fahrenheit or 38.9 degrees Celsius)
  • Swollen lymph nodes (glands) in the neck
  • Red, swollen tonsils (tissue located inside the mouth, at either side of the throat)
  • White spots or coating of the tonsils (may also be yellow or gray in color)
  • Abdominal pain
  • Headache
  • Difficulty swallowing
  • Loss of appetite
  • Nausea andvomiting
  • Rash
  • Weakness

Symptoms may vary when strep throat occurs in young children. Signs of strep throat in infants include:

  • Low-grade fever (under 102 degrees Fahrenheit or 38.9 degrees Celsius)
  • Thick and bloody nasal discharge

Signs of strep throat in toddlers include:

  • Low-grade fever (under 102 degrees Fahrenheit or 38.9 degrees Celsius)
  • Thick and bloody nasal discharge
  • Increased irritability
  • Sleeplessness
  • Loss of appetite
  • Swollen neck glands

The presence of any of the following may indicate a viral infection rather than strep throat:

  • Runny nose
  • Coughing
  • Hoarseness
  • Red eyes

Some people do not display the symptoms of the infection but nonetheless are carriers of the bacteria. In other cases, symptoms of strep may be especially severe and indicate more serious illness. Prolonged or high fever, breathing problems or significant difficulty swallowing are signs of strep that indicate a medical emergency that requires immediate attention.

Untreated strep throat can spread to other areas of the body and lead to serious medical conditions. However, these complications are rare in the United States since prompt and effective treatment is delivered in most cases of strep throat. These complications include:

  • Rheumatic fever. A severe inflammatory disease that causes joint pain and may cause permanent heart problems. Rheumatic fever occurs approximately 18 days after an episode of strep throat, according to the National Institutes of Health (NIH). It most often affects children.
  • Glomerulonephritis. Inflammation of the kidneys that may lead to kidney failure. This condition may occur after an untreated case of strep throat, although it occurs more often after a strep infection of the skin.
  • Sydenham chorea. Sometimes follows rheumatic fever. This disorder involves uncontrolled, jerking movements of the muscles in the torso, arms and legs.

If a person develops a skin rash shortly (often 24 to 48 hours) after the strep throat symptoms begin, it may indicate scarlet fever. A rash accompanied by swelling of the joints or shortness of breath after a strep infection may indicate rheumatic fever. People who notice these symptoms should seek immediate medical attention.

Diagnosis methods for strep throat

People who have a sore throat without a runny nose that lasts for more than 48 hours are urged to consult a physician. The physician will perform a physical examination that will likely include a visual inspection of the throat. A tongue depressor may be used to enable clear viewing of the back of the throat. A medical history may be compiled, which can include questions about the frequency of the patient’s throat infections. The patient may also be referred to an ear, nose and throat specialist.

Strep throat cannot be diagnosed strictly by symptoms and physical examination. The only way to identify the presence of strep throat is through the following diagnostic tests:

  • Rapid strep test (also called the rapid antigen test). A physician will swab the surface of the tonsils, located at the back of the patient’s throat for a tissue sample. This can be analyzed and results are typically available within about 15 minutes. It can detect the strep bacteria in 75 percent to 85 percent of strep throat cases, according to the American Academy of Family Physicians (AAFP).

  • Throat culture. A physician swabs the patient’s tonsils(similar to the method used for the rapid strep test) and the tissue sample is then sent to a laboratory for analysis. Results are generally not available for at least a day or two.

Generally, both tests are performed, particularly if the rapid strep test is negative. The rapid strep test allows treatment to begin immediately (if strep throat is detected) and the throat culture is used to confirm this result. Occasionally, the throat culture (a more sensitive test) may detect a strep throat infection that was missed during the rapid strep test. It should be noted that recent antibiotic therapy or gargling with some types of mouthwash prior to these tests may affect results.

A new diagnostic test has been developed that uses DNA technology, called the rapid DNA test. It provides results within a few hours, and may be more sensitive than the rapid antigen test. Patients are urged to consult with the physician about the availability of this test.

Family members who are not currently displaying symptoms of strep throat will sometimes receive a rapid strep test and throat culture to help determine if they are carriers.

It is important to note that strep tests and cultures sometimes miss a number of other types of conditions that also cause severe sore throats. These include severe tonsillitis or tonsillar abscess, diphtheria, and infections of the throat resulting from oral sex. The presence of bacteria growing in the blood (septicemia) can also cause symptoms similar to strep. As a result, further testing may be necessary to rule out these conditions in patients who have sore throats but who test negatively for strep. In addition, a physician may perform a rapid influenza test to check for the presence of influenza, which has symptoms that often are similar to strep.

Treatment options for strep throat

Antibiotics are usually required to treat strep throat. While these are often not given until tests confirm the diagnosis of strep through, rapid stress tests allow the diagnosis to be made within minutes. Even without antibiotics, strep infection will clear on its own. However, antibiotics are necessary to kill the bacteria, limit the spread of infection and prevent medical complications. People who do not take antibiotics are contagious for a longer period of time and are at greater risk of developing serious complications related to the strep.

Antibiotics may be provided in pill, liquid or injectable form. Patients with strep throat should begin to feel better within a day or two of beginning antibiotic treatment. It is important to take the complete course of antibiotics prescribed, which usually lasts for 10 days to 14 days. Failure to take the entire course of treatment may increase the risk of serious medical complications (e.g., rheumatic fever, glomerulonephritis) or lead to development of antibiotic-resistant bacteria.

People with strep throat may continue to be contagious for at least 24 hours after beginning antibiotic treatment. They should not return to work or school until they have taken antibiotics for at least one day, the fever is gone and they feel better. Antibiotic treatment limits the spread of infection but does not prevent strep throat from recurring in a particular patient. Patients who are not treated with antibiotics may be contagious for weeks after an infection.

If a patient who has tested positive for strep throat does not respond to antibiotic treatment, it may be because that patient is a carrier (carries the bacteria in the body but never develops an infection). In addition, the existing condition may not be strep throat at all, but a viral infection. A way to confirm this is to test the patient for strep throat when signs of infection are no longer present. A healthy, asymptomatic patient who tests positive for strep throat is considered a carrier. It is not usually necessary to treat carriers, who are much less contagious than people who have symptoms of strep throat.

Patients can manage symptoms by getting plenty of rest and nourishment. Adequate fluid intake (e.g., water, juice, broth) can help prevent dehydration. In addition, certain over-the-counter pain medications (e.g., acetaminophen, ibuprofen) can help reduce the fever and pain associated with strep throat. Parents should never give aspirin to children or adolescents since it may increase the risk of Reye syndrome, a potentially fatal condition.

Additional self-treatment methods for strep throat include:

  • Gargle with warm salt water
  • Drink cool or warm liquids
  • Eat soft foods (e.g., soup, popsicles)
  • Use a humidifier

Patients are urged to avoid consuming acidic products (e.g., orange juice, lemonade), since they may sting the throat. Environments that include cigarette smoke or fumes from paint or cleaning products should also be avoided, since these may irritate an already sore throat. In addition, patients are urged to ask their physician about whether or not throat lozenges may help. Parents of children with strep throat are urged to remember that lozenges can pose a choking hazard for young children. Some lozenges may aggravate the symptoms of strep throat.

Although rare, a tonsillectomy is sometimes recommended for patients with repeated episodes of strep throat (e.g., more than five episodes in one year). Some studies suggest that strep throat infections occur much less often after a tonsillectomy. Patients are urged to consult their physician to weigh the benefits and risks of this type of surgery.

Patients should call their physician if they notice any of the following after completing their treatment:

  • Cola-colored urine
  • Fever
  • Pain or swelling in the joints
  • Rash
  • Shortness of breath

Prevention methods for strep throat

Strep throat is a bacterial infection that can be easily spread. The infection can be acquired anywhere that people congregate, such as at home, work, school or daycare facilities. 

The best way to prevent strep throat is to avoid exposure to the bacteria that cause strep throat. These bacteria can be transmitted by saliva or nasal discharge from an infected person. It may be difficult to completely avoid infected people, however, since some people can be carriers – they may carry and transmit the bacteria, but display no symptoms of infection themselves.

Methods that can help prevent the spread of strep throat include:

  • Wash hands with hot soapy water frequently
  • Cover mouth and nose when coughing or sneezing
  • Immediately dispose of used tissue
  • Avoid touching eyes or mouth
  • Avoid sharing eating utensils, food or any items that may spread germs
  • Replace toothbrush after respiratory infections

Strep throat is a bacterial infection that can be easily spread. The infection can be acquired anywhere that people congregate, such as at home, work, school or daycare facilities. 

The best way to prevent strep throat is to avoid exposure to the bacteria that cause strep throat. These bacteria can be transmitted by saliva or nasal discharge from an infected person. It may be difficult to completely avoid infected people, however, since some people can be carriers – they may carry and transmit the bacteria, but display no symptoms of infection themselves.

Methods that can help prevent the spread of strep throat include:

  • Wash hands with hot soapy water frequently
  • Cover mouth and nose when coughing or sneezing
  • Immediately dispose of used tissue
  • Avoid touching eyes or mouth
  • Avoid sharing eating utensils, food or any items that may spread germs
  • Replace toothbrush after respiratory infections

Questions for your doctor about strep throat

Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions related to strep throat:

  1. I have a sore throat. How can I tell if it is strep throat?
  2. What type of treatment will I need for strep throat?
  3. For how long will I have to take antibiotics?
  4. What can I do to make myself comfortable at home while I recuperate from strep throat?
  5. Do you recommend specific over-the-counter pain relievers? What are their side effects? Are there any I should avoid?
  6. What change in symptoms should I report to you?
  7. Are other household members at risk of contracting strep throat from me?
  8. For how long will I be contagious?
  9. When do you recommend that I return to work/school, or resume normal activities?
  10. How can I reduce the likelihood that I will catch strep throat (or another infection) while at work or school?
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