Strep throat

In this article:

• What Is strep throat?
• How You Get Strep Throat
• Symptoms
• When to see a doctor
• Causes
• Risk factors
• Complications
• Spread of infection
• Prevention
• Diagnosis
• Infectious mononucleosis
• Recommendations
• What is new in Strep Throat diagnosis?
• References

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What Is strep throat?

Strep throat is a common name of a pharyngitis caused by the bacteria Streptococcus. Honestly, I do not know even one person who did not have it at least once in a lifetime. That is how frequent it is. 

Here is some statistics. Group A Streptococcus (GAS) is the most common bacterial etiology for acute pharyngitis and accounts for 5 to 15% of all adult cases and 20 to 30% of all pediatric visits to the clinic. It is rare to be hospitalized with Strep throat.

Sore throat (pharyngitis) does not necessarily mean Strep throat. Acute pharyngitis is one of the most common complaints that a physician encounters in the ambulatory care setting, accounting for approximately 12 million visits annually or 1 to 2% of all ambulatory care visits annually. 

Typically, Strep throat peaks during childhood and adolescents and accounts for 50% of all visits every year. Although there are a large number of visits each year for pharyngitis, the majority of these cases are viral and recover without specific treatment.

Some people have Strep bacteria living in their tonsils without causing infection. This is called “asymptomatic carrier”. That can give false diagnosis when the child has a viral illness, but the throat swab is positive for strep. 

Strep is treated with the antibiotics. But it is extremely important that physicians not over-diagnose GAS pharyngitis to prevent inappropriate administration of antimicrobials to large numbers of patients with non-streptococcal pharyngitis. Such therapy unnecessarily exposes patients to the expense and hazards of antimicrobial therapy.

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How You Get Strep Throat

Strep is a bacterium that is most frequently transmitted by sick with strep throat children through saliva. So, you can get it through shared utensils, cups and toys (for small children).

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Symptoms

Symptoms alone are not so different between different types of pharyngitis. Doctors have special scoring system to see when strep is the most likely diagnosis. Here are the most common symptoms of Strep throat:

1. Acute onset – usually a child or adult becomes ill and gets all symptoms within few hours
2. Fever, most of the time very high (>102 f)
3. Tonsillar exudates – tonsils increase in size, become red and have spots of whitish-yellowish film
4. Absence of cough, runny nose, or other viral symptoms
5. Tender anterior adenopathy – lymph nodes under the chin become large and hurt
6. Palatal petechiae, strawberry tongue, red swollen uvula, or scarlatiniform rash may also be present.

When to see a doctor

Most of the time parents decide to see a doctor when the child becomes rapidly sick. That is a good idea, because a primary care practitioner can decide if antibiotics are needed. Strep produces lots of toxins, so even an adult will feel lousy with that sickness.

There is no question you need to see a doctor if right before your child got sick you got a notice from school that someone else has a Strep Throat at school. You should also notify a childcare or school if your child was confirmed to have Strep.

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Causes

There is only one cause – a Group A beta-hemolytic streptococcal (GABHS) infection

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Risk factors

In patients with sore throat, the likelihood of Strep pharyngitis is highest in children 5 to 15 years of age (37%) and lower in younger children (24%) and adults (5% to 15%). 

Strep throat is more common in late winter and early spring. Colonization (having a positive Strep culture or antigen without symptoms) is also higher in winter months, and while up to 20% of school age children are colonized with GAS in their throat during this time, colonization has not been shown to contribute to the spread of disease.

Complications

Children with a missed diagnosis of GAS tonsillitis are at increased risk of developing suppurative (creating pus) complications such as otitis media, sinusitis, and peritonsillar abscess (PTA).

Spread of infection

Children sick with the strep may infect all school or daycare. Families with many children may have all of them sick from each other and transmit it further into different schools and childcare facilities. That is why strep is constantly spread in the communities.Inflammatory reactions. Acute rheumatic fever (ARF) occurs primarily in untreated school-aged children aged 5∼14 years with previous history of untreated tonsillitis.

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Prevention

The best prevention is following good hygiene practices, especially at schools and daycare centers:

• Frequent hand washing
• Prevention of dishes and utensils sharing
• Washing of the common surfaces and toys
• Good ventilation and non-crowded indoor spaces

As COVID-19 taught us preventive practices that help stopping the spread of this virus, same measures are actually helpful in Strep and other contagious infections.

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Diagnosis

It is almost impossible to self-diagnose Strep Throat, although you could highly suspect it in certain cases. There are so many other viruses that could cause very similar symptoms, that it is always best to confirm it with the primary care practitioner.

As a rule of thumb, if you already know about the contact with someone who was diagnosed with a Strep, there is a high likelihood you or your child have the same! But if you know that it is a Hand-Foot-Mouth disease that was found in a childcare – the best bet it is the same in your case.

Infectious mononucleosis

(“kissing disease”) should be considered in teenagers with swollen lymph nodes in the back of the neck and in other places of the body, fatigue, large spleen, sometimes yellowish eyes, and abnormal blood white cell count (atypical lymphocytosis). 

Hand-foot-and-mouth disease should be considered in patients of all ages with oral ulcers (and not just on the tonsils), severe throat pain, and rash on the hands and feet.

Physicians diagnose strep (GABHS) pharyngitis using an approach that combines a validated clinical decision rule (e.g., modified Centor score, FeverPAIN score) with selective use of rapid antigen detection testing.

Is strep throat culture needed?

Not really, if the contacts with Strep throat are known and the symptoms are straight-forward. Throat culture is needed in the situations when a doctor is not sure it is really strep, or if the treatment did not work.

Recommendations

• Swabbing the throat and testing for GAS pharyngitis by rapid antigen detection test (RADT) and/or culture should be performed because the clinical features alone do not reliably discriminate between GAS and viral pharyngitis except when overt viral features like rhinorrhea, cough, oral ulcers, and/or hoarseness are present. In children and adolescents, negative RADT tests should be backed up by a throat culture (strong, high). Positive RADTs do not necessitate a back-up culture because they are highly specific (strong, high).
• Routine use of back-up throat cultures for those with a negative RADT is not necessary for adults in usual circumstances, because of the low incidence of GAS pharyngitis in adults and because the risk of subsequent acute rheumatic fever is generally exceptionally low in adults with acute pharyngitis (strong, moderate). Physicians who wish to ensure they are achieving maximal sensitivity in diagnosis may continue to use conventional throat culture or to back up negative RADTs with a culture.
• Anti-streptococcal antibody titers are not recommended in the routine diagnosis of acute pharyngitis as they reflect past but not current events; strong, high).
• Testing for GAS pharyngitis usually is not recommended for children or adults with acute pharyngitis with clinical and epidemiological features that strongly suggest a viral etiology (eg, cough, rhinorrhea, hoarseness, and oral ulcers; strong, high).
• Diagnostic studies for GAS pharyngitis are not indicated for children <3 years old because acute rheumatic fever is rare in children <3 years old and the incidence of streptococcal pharyngitis and the classic presentation of streptococcal pharyngitis are uncommon in this age group. Selected children <3 years old who have other risk factors, such as an older sibling with GAS infection, may be considered for testing (strong, moderate).
• Follow-up posttreatment throat cultures or RADT are not recommended routinely but may be considered in special circumstances (strong, high).
• Diagnostic testing or empiric treatment of asymptomatic household contacts of patients with acute streptococcal pharyngitis is not routinely recommended (strong, moderate).

What is new in Strep Throat diagnosis?

Here is new research that was recently published by the group of scientists from Texas Tech University: 

“Processing Method for Detecting Strep Throat (Streptococcal Pharyngitis) Using Smartphone” by Behnam Askarian , Seung-Chul Yoo , Jo Woon Chong . 2019 Jul 27;19(15):3307. doi: 10.3390/s19153307.

Abstract: In this paper, we propose a novel strep throat detection method using a smartphone with an add-on gadget. Our smartphone-based strep throat detection method is based on the use of camera and flashlight embedded in a smartphone. 

The proposed algorithm acquires throat image using a smartphone with a gadget, processes the acquired images using color transformation and color correction algorithms, and finally classifies streptococcal pharyngitis (or strep) throat from healthy throat using machine learning techniques. 

Our developed gadget was designed to minimize the reflection of light entering the camera sensor. The scope of this paper is confined to binary classification between strep and healthy throats. Experimental results show that our proposed detection method detects strep throats with 93.75% accuracy, 88% specificity, and 87.5% sensitivity on average.

Wow, that is great – may be in a nearest future there will be no need to drag a sick child to the doctor – just get a picture and ask for a virtual visit!

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References

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