What Causes Strep Throat and When to See a Doctor

Streptococcal pharyngitis, commonly known as “strep throat,” is a mild but contagious bacterial infection that affects the larynx, tonsils, and/or pharynx (throat).

Strep throat is caused by group A Streptococcus, a strain of bacteria that is also associated with mild skin infections, cellulitis, impetigo, and other serious problems. (1) This disease has a sudden onset, usually with a sore throat and can be relieved through proper antibiotics along with other self-care measures.

If left untreated, strep throat can spread easily to other people and also induce severe medical problems in the infected individual. It is, therefore, necessary to take steps to keep yourself from contracting or spreading strep throat.

Mode of Transmission

Strep bacteria can spread in the following ways:

1. Airborne droplets

When an individual with strep throat breathes, sneezes, or coughs, the bacteria-containing respiratory droplets are released in the surrounding environment. Breathing in the airborne droplets can spread the infection to a healthy individual.

2. Saliva

Sharing foods or drinks with an infected individual is another mode of strep transmission.

3. Physical contact

People with a strep infection inadvertently carry the bacteria on their hands and can contaminate anything or anyone they touch. Shaking hands with them or touching the objects they have used may transfer the bacteria to your hand.

If you touch your mouth or nose without washing your hands first, the bacteria can then enter your body and cause infection.

Symptoms of Strep Throat

Strep throat gives rise to the following symptoms:

Medical Treatment for Strep Throat

Antibiotics are the standard treatment for strep throat but must be used judiciously to prevent the induction of drug resistance in bacteria and other side effects in your body.

Antibiotics should only be provided when the tests confirm the presence of strep bacteria. Patients without significant symptoms may not benefit from the use of antibiotics.

Unnecessary use of antibiotics may have more risks and side effects than benefits. (3)

To curb the growth of strep bacteria, your doctor may prescribe antibiotics such as penicillin and amoxicillin.

The course of the antibiotics is usually 10 days long and should be completed even if the symptoms subside early to eliminate every trace of bacteria and prevent a possible relapse of the infection.

These medications may also be prescribed to treat the symptoms associated with strep throat:

• Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and naproxen, which help relieve pain as well as reduce swelling and fever
• Analgesics, such as acetaminophen, which reduce fever, pain, and soreness in the throat

Diagnosing Strep Throat

The following tests can help indicate the presence of strep bacteria in the throat:

• The rapid strep test is the quickest and most commonly used method for diagnosing strep throat. Using a long cotton swab, the doctor collects a mucus sample from the back of the throat for lab testing. This test takes around 15 minutes to provide results.
• A throat culture is a more comprehensive test that involves collecting a mucus sample from the throat and then sending it to the lab for culture. This test takes around 2 days to yield results.

These tests are not always 100% accurate. A negative result only indicates the absence of strep bacteria. When the tests are negative, the sore throat results from other reasons not detectable with these limited tests. Further testing may need to be done. 

Risk Factors for Strep Throat

Certain factors can make you more susceptible to strep throat:

• Strep throat is most widespread in children between 5 and 15 years of age. However, it can occur in people of all age groups.
• The risk of contracting strep throat increases when you come into contact with an infected person.
• The disease can easily spread in crowded places such as schools, day-care centers, and military barracks.
• Adults who are constantly surrounded by children can contract the disease easily.
• Strep throat is prevalent year-round, but it tends to spread more easily in winter and early spring.

Complications of Strep Throat

A severe infection caused by strep bacteria may spread to other body parts, including:

• Middle ear: The bacteria can spread and grow behind the eardrum, causing inflammation, also known as otitis media.
• Sinuses: The spread of bacteria to the air cavities around the eyes and nose can cause sinusitis.
• Tonsils: An infection in the tonsils can cause tonsillitis. The bacteria may spread behind the tonsils and form an abscess, known as a peritonsillar abscess (quinsy).
• Voice box: An infection in the throat may spread to the structures of the voice box and cause swelling, resulting in problems speaking and breathing.

In rare cases, the following complications may arise:

• Scarlet fever: Scarlatina, or scarlet fever, develops due to infection by strep bacteria. The symptoms include high fever, bright-red rashes on the body, and sore throat.
• Post-streptococcal glomerulonephritis: After a period of 10–14 days of infection with strep bacteria, swelling in the kidney may be observed.
• Rheumatic fever: Improper treatment of strep throat or scarlet fever can lead to the development of rheumatic fever. This poses an adverse effect on the joints, skin, brain, and heart. (4)
• Meningitis: The spread of infection to the spinal canal and the covering of the brain can cause inflammation of these structures called meningitis.

When to See a Doctor

It is advised to consult your doctor if you experience the following problems along with a sore throat:

Final Word

Proper self-care and a full course of antibiotics can treat the majority of cases of strep throat.

It is important to get ample rest so that your body can focus on fighting the infection. If the symptoms do not subside, immediate medical attention is necessary to avoid undue complications later.

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