Medical Conditions - Strep Throat

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Strep Throat

(Throat Infection, Strep, Streptococcal Pharyngitis)

The Facts

Strep throat is the most common of bacterial infections that cause sore throat. It accounts for about 5% to 15% of all sore throats in adults and 20% to 30% in children.

It’s called "strep" throat because the bacterium that causes it belongs to the class known as group A streptococcus (GAS). The initials GAS are sometimes used, and doctors may talk about a GAS throat infection. Although strep throat can occur any time during the year, late winter and early spring are considered to be peak seasons for strep throat infections.

Sore throat is one of the leading complaints that bring people to the doctor’s office, and about 40% to 50% of sore throats are treated with antibiotics. However, fewer than half of the people given antibiotics actually have bacterial infections. Most of the rest have viral infections that are not affected by antibiotics.

When used appropriately, antibiotics are very helpful in fighting infection. However, antibiotics used inappropriately can be bad for you, killing harmless bacteria that may be keeping dangerous bacteria out of your intestines. It is important to learn about appropriate (and unnecessary) antibiotic use, which includes not pressing a doctor for antibiotics when the doctor says they aren’t needed.


Streptococci are everywhere – many people carry it on their skin and throat. They don’t always cause disease: that is, they don’t always cause strep throat infection. However, streptococci are infectious. They are passed around in the same way as cold viruses, by coughing, sneezing, or getting mucus or saliva on the hand, then touching other people. They are less contagious than a cold virus, however.

Symptoms and Complications

Streptococcal pharyngitis, as strep throat is formally known, causes these symptoms:

  • fever (greater than 38°C or 100.4°F), chills, and sweating
  • headache
  • nausea and vomiting (sometimes)
  • sore throat
  • swollen tonsils and lymph nodes in the neck
  • white patches on the tonsils

Coughing, runny nose, stuffiness, and sneezing aren’t associated with strep throat and are usually signs of a viral infection. It’s also rare for streptococcus to invade the larynx (voice box), causing hoarseness – this is far more likely with a virus. Of course, it’s possible to have both viral and bacterial infections at the same time.

It takes about 24 to 72 hours for the bacteria to incubate in the body, or become great enough in number before symptoms are seen.

Before the discovery of antibiotics, strep throat often led to serious complications. The most dangerous of these was rheumatic fever. In rheumatic fever, the immune system inflicts serious damage on the vital heart valves. This can leave a person vulnerable to heart disease later in life. Fortunately, this is a very rare occurrence today.

Other possible complications include immune overreaction in the joints (arthritis) or in the kidneys (glomerulonephritis). The bacteria can also travel up tubes that link the throat to the middle ears (the eustachian tubes). This is especially likely in young children, whose ear tubes aren’t yet fully developed. This causes otitis media, which is an infection of the middle ear. The bacteria may also get into the lining of the brain and cause meningitis.

All of these complications are extremely rare, except otitis media. A few children develop a chronic pattern of recurring throat and ear infections.

The syndrome known as scarlet fever is a fairly rare, usually mild complication of strep throat, and is essentially a strep throat accompanied by a temporary red rash. The rash is most prominent on the abdomen and the sides of the chest. Some skin may peel when it subsides.

If complications do appear, they often come 1 to 6 weeks after the strep throat infection. Call a doctor if you see any of these symptoms:

  • earache
  • joint pain
  • nosebleeds
  • severe abdominal pain
  • stiff neck
  • sudden high fever
  • red rash
  • stomach pain

Making the Diagnosis

We’ve all opened our mouths and said "aaah" at some point. That’s a simple test for strep throat. Usually, if bacteria are present, the uvula (the punching-bag-shaped object hanging at the back of the mouth) and the tonsils are red and inflamed and dotted with pus deposits. Another finding may be tiny reddish spots called petechiae on the roof of the mouth.

Even doctors can’t always tell a bacterial infection from a viral infection by the symptoms alone. The standard test is a throat swab to gather bacteria from inside the throat, to be sent to a lab or tested in the doctor’s office using a special kit. Results usually take 1 to 2 days. Doctors may also use a rating system called the McIsaac’s scorecard to help diagnose strep throat. If you have a sore throat and score of 4 or 5 out of 5 (fever, pus on the tonsils, swollen neck nodes, less than 15 years old and no cough), your doctor may prescribe antibiotics before getting the results of the swab.

A rapid antigen test may be done to see if you have sore throat caused by GAS. A throat swab is taken and used to test for the presence of a substance specific to the bacteria. The rapid antigen test is fast, often taking less than 15 minutes. Results take longer if the swab is sent to a laboratory for testing. Some pharmacies now offer rapid antigen tests.

Treatment and Prevention

The vast majority of streptococcal throat infections will go away on their own even without treatment, and the chance of rheumatic fever or meningitis is extremely small even if you don’t go to the doctor. The main reason to use antibiotics is to prevent these very rare but serious complications; not to treat the throat symptoms.

The most commonly used antibiotics to treat strep throat are from the penicillin class of antibiotics. They are available by prescription and come as oral tablets, capsules, or liquid suspensions. They are prescribed for a period of 5 to 10 days, depending on the antibiotic used. Be sure to mention to your doctor if you have allergies to any medications.

Most of the people given oral antibiotics for sore throat don’t have bacterial infections, so they can’t possibly benefit from these medications. They can, however, be harmed by antibiotics, which leave the body more vulnerable to infection. You shouldn’t take antibiotics for a sore throat unless you’ve had a bacterial infection properly diagnosed or unless otherwise instructed by your doctor. However, if you are treated with antibiotics, finish the course of treatment! This will help to prevent antibiotic resistance.

In addition, your doctor may recommend taking acetaminophen or ibuprofen for relieving fever and pain.

These tips may help people to stay healthy in the presence of the streptococcus bacteria:

  • Anyone taking antibiotics should finish the prescription even if symptoms are gone.
  • Children with the illness shouldn’t go to school until they’ve been on antibiotics for at least 24 hours.
  • Children should be taught to cover their nose and mouth if they cough, for example, by coughing into their sleeve or into a tissue.
  • If you’re taking antibiotics, consider replacing the "good" bacteria in your digestive tract. You can do this by eating yogurt containing live Lactobacillus acidophilus. It is also available in a pill form. Ask your health care provider if taking Lactobacillus acidophilus is appropriate for you.
  • People with strep throat and those around them should wash their hands frequently.

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