Strep throat is a sore throat caused by bacteria known as Streptococcus pyogenes, or group A streptococcus. The bacteria spread when a person coughs, sneezes, or talks. Symptoms can include pain, swelling, small spots in the mouth, and more.

“Sore throat” is the general term for any condition where the throat feels scratchy, tender, and possibly painful. Strep throat, however, is a sore throat caused by a specific type of bacteria.

This article will cover the causes, symptoms, diagnosis, and treatment of strep throat.

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Doctors may also refer to strep throat as streptococcal pharyngitis or streptococcal sore throat. The only cause of strep throat is group A Streptococcus (group A strep).

These bacteria are highly transmissible and can spread through respiratory droplets that a person makes when they sneeze, cough, or talk.

People may also contract strep throat by touching surfaces that someone with strep throat previously touched, such as doorknobs, kitchen utensils, or bathroom objects, and then touching their mouth or nose.

Most of the time, strep throat is not serious, and a person will notice that their symptoms resolve within 1–3 days of starting a course of antibiotics.

Strep throat is more common in children and adolescents. This is because younger people have not experienced exposure to as many germs and have not acquired immunity to many of them. Additionally, strep throat thrives in crowded settings, such as day care centers and schools.

While a person can get strep throat at any time of year, infections peak in winter and early spring. This is sometimes called “strep throat season.” There are some reasons for this.

For example, people tend to move indoors when it gets cold. Spending more time in enclosed spaces makes it much easier to pass on and catch infections like strep throat. Additionally, the dry air that is more common in colder months can dry out the nose and throat, reducing natural defenses to infections.

According to the Centers for Disease Control and Prevention (CDC), 2–5 days can pass between the time a person is exposed to group A strep and when they feel the symptoms of strep throat. This is called the incubation period.

The symptoms of strep throat are similar to a sore throat and include:

However, people with strep throat may sometimes have no signs or symptoms. These people might not feel ill, but they can still potentially pass the infection onto others.

In most cases, a sore throat is just one of the symptoms of another infection such as the common cold and will resolve itself in a few days.

However, a person should contact a doctor if:

  • symptoms do not get better or begin to get worse after a few days of at-home care
  • sore throats are frequent and do not respond to pain relief medication
  • there is persistent fever, as this often indicates an infection that a doctor should diagnose and treat as soon as possible

Be sure to seek urgent medical attention if:

People should also contact a doctor if they have a weakened immune system, such as people living with HIV or AIDS, diabetes, or anyone receiving chemotherapy, radiotherapy, steroids, or immunosuppressant medications.

If a person thinks that they have strep throat, the doctor will examine them and look for signs of strep throat or a throat infection.

Most sore throats occur due to a viral infection. Because of this, it is sometimes hard to know, initially, whether a sore throat is caused by a virus or by bacteria.

If a doctor thinks a person may have strep throat, they will order tests to determine if group A strep is causing the sore throat. These tests involve using a swab to collect a sample from the back of the throat.

A rapid antigen test, or rapid strep test, detects group A strep antigens from a throat swab sample. An antigen is any substance that prompts an immune response, such as bacterial proteins. A rapid strep test can give results quickly, often in as little as 10 minutes.

While rapid strep tests can give results in a short amount of time, they can miss some infections. A 2016 review estimated that a rapid strep test would return a false-negative result in 14 of 100 children with strep throat.

If a rapid strep test is negative, but a doctor still suspects strep throat, they will order a throat culture to see if group A strep grow from a throat swab sample. A throat culture is the gold standard diagnostic test for strep throat, but it typically takes 24–48 hours to get results.

Nucleic acid tests for strep throat are also available. These detect the presence of group A strep DNA in a throat swab sample. However, due to the higher costs of these tests, doctors more commonly use rapid strep tests and throat swabs.

If testing indicates that a person has strep throat, a doctor will prescribe a course of antibiotics. These are drugs that can kill bacteria or stop their growth. Most people with strep throat will need to take antibiotics for 10 days.

Easing symptoms and shortening the length of a person’s illness is not the only benefit of antibiotics. These medications can also reduce the likelihood that the infection will spread to others and prevent potentially serious complications.

Typically, doctors use antibiotics like penicillin or amoxicillin to treat strep throat. Those with an allergy to penicillin may receive clindamycin, clarithromycin, or azithromycin instead.

It is important that a person takes the entire course of antibiotics, even if they begin to feel better shortly after starting them. Not taking the entire course can lead to the infection not clearing completely.

If a person tests positive for strep throat but does not have any symptoms, they typically do not need antibiotics. According to the CDC, these people are less likely to pass on the infection to others and are at a lower risk of complications.

Self-care at home

Doing the following things at home can also help with recovery:

  • avoiding foods or drinks that are very hot, as they may irritate the throat
  • consuming cool drinks and cool, soft foods to help ease pain or discomfort
  • consuming warm drinks
  • avoiding smoking and smoky environments, as these will irritate the throat
  • sucking on ice cubes to help with throat irritation
  • gargling with slightly salted warm water or mouthwash to reduce swelling and alleviate pain
  • taking over-the-counter (OTC) medicines such as acetaminophen or ibuprofen to help ease pain, swelling, and fever

Pediatric treatment

The treatment of strep throat in children is much the same as in adults. Doctors will prescribe a child with strep throat a course of antibiotics.

Parents and caregivers can also help keep a child comfortable during recovery by:

  • giving them cool foods such as ice cream or popsicles to help to ease throat discomfort
  • having older children gargle with warm salt water or suck on ice cubes, which may help with pain or discomfort
  • providing liquid formulations of OTC medicines like acetaminophen or ibuprofen to younger children if needed, to help with pain, swelling, and fever
  • providing the above medications in pills or tablet form to older children, as needed

Children and teenagers should never take aspirin.

Strep throat is easy to treat. However, if left untreated, there is a chance it may lead to potentially serious complications.

These typically involve the spread of the infection to other areas of the body and can include:

  • sinusitis, an infection of the sinuses
  • otitis media, an infection of the middle ear
  • bacteremia, where a bacterial infection enters the bloodstream
  • meningitis, an inflammation of the tissue surrounding the brain and spinal cord
  • scarlet fever, which results from bacterial toxins and produces a scarlet rash
  • rheumatic fever, an inflammatory condition that can damage the heart
  • a peritonsillar abscess, a pus-filled pocket near the tonsils
  • retropharyngeal abscess, a pus-filled pocket in the tissues at the back of the throat
  • reactive arthritis, a type of inflammatory arthritis
  • post-streptococcal glomerulonephritis, an inflammation of the kidneys that can lead to kidney damage
  • streptococcal toxic shock syndrome, a serious infection that happens when group A strep spread into the bloodstream and deeper tissues
  • pediatric autoimmune neuropsychiatric disorder associated with streptococcal infections (PANDAS), a condition that causes sudden changes in behavior, movement, and personality in children following a group A strep infection

The timing of the progression of strep throat into a more serious illness can depend on the type of complication.

For example, an abscess may form during or shortly after strep throat. In this case, a person may notice that their symptoms do not get better, get worse, or recur. New symptoms like swelling in the neck or face, trouble swallowing even saliva, or difficulty opening the mouth may also develop.

Some strep throat complications take longer to come on. For example, post-streptococcal glomerulonephritis typically develops 10 days after strep throat symptoms begin. Rheumatic fever can take even longer, appearing 1–5 weeks after a person develops strep throat.

It is important that a person follows their treatment plan carefully and pays attention to their body. If new, concerning symptoms develop or symptoms do not improve after 48 hours of taking antibiotics, a person should call a doctor.

Everyone gets a sore throat at some point in their lives, whether due to a bacterial or viral infection or another cause.

The following tips may help reduce the frequency of sore throats, including those due to strep throat:

  • Keep hands clean: Regular hand washing with soap and water is an effective way of preventing most infections.
  • Cover the mouth when coughing: This protects other people. Coughing into the inside of the elbow, rather than into the hands, may prevent passing on infections.
  • Isolate personal items: People with a sore throat should not share items such as drinking glasses and eating utensils with others.
  • Clean high touch surfaces: Make sure to regularly clean high touch surfaces, including doorknobs, countertops, and appliance handles.
  • Avoid close contact with those who are ill: If a person is sick with a sore throat, avoid close contact with them until they feel better.
  • Make lifestyle choices that can boost the immune system: These may include:

Strep throat is a sore throat that results from a bacterial infection. It spreads easily from person to person and is more common in children and adolescents. It is also more likely to occur in the colder months of the year.

If a person has strep throat, a doctor can treat the infection with a course of antibiotics. It is important to take the entire course of antibiotics to clear the infection completely.

If left untreated, the infection can spread to other areas of the body and cause potentially serious complications. Because of this, a person should contact a doctor if they think that they have symptoms. Simple tests can detect the presence of the bacteria that cause strep throat.