Strep throat

Alternative names
Pharyngitis - streptococcal; Streptococcal pharyngitis

Strep throat is caused by Streptococcus bacteria. It is the most common bacterial infection of the throat.

Causes, incidence, and risk factors

Strep throat is most common in children between the ages of 5 and 15, although it can happen in younger children and adults. Children younger than 3 can get strep infections, but these usually don’t affect the throat.

Strep throat is most common in the late fall, winter, and early spring. The infection is spread by person-to-person contact with nasal secretions or saliva, often among family or household members.

People with strep throat get sick 2-5 days after they are exposed. The illness usually begins suddenly, with a fever that peaks on the second day. Many also have sore throat, headache, stomachache, nausea, or chills.

In some people, strep throat is very mild, with only a few of these symptoms. In others, strep throat is severe. There are many strains of strep. Some strains produce toxins that can lead to a scarlet fever rash. This rash is thought to be an allergic reaction to the toxins. Untreated, strep throat can sometimes lead to Rheumatic fever. Kidney complications are among the other possibilities.


  • sore throat  
  • red throat  
  • difficulty swallowing  
  • fever that begins suddenly  
  • tender, swollen Lymph nodes in the neck  
  • general discomfort, uneasiness or ill feeling  
  • nausea  
  • loss of appetite  
  • rash

Additional symptoms that may be associated with this disease:

  • tongue problems  
  • neck pain  
  • nasal discharge  
  • Nasal congestion  
  • muscle pain  
  • joint stiffness  
  • headache  
  • abnormal taste

Signs and tests

A throat swab can be tested for culture. A rapid antigen test is quicker, but misses a few of the cases.


Even though the sore throat usually gets better on its own, people who have strep throat SHOULD take antibiotics to prevent more serious complications of this infection, including Rheumatic fever. Penicillin has been traditionally recommended. However, resistance to penicillin is increasing, and cephalosporins may be more effective in some situations.

Be aware that most sore throats are caused by viruses, not strep. The Centers for Disease Control and Prevention (CDC) recommends AGAINST treating sore throats with antibiotics unless the strep test is positive. Strep cannot be diagnosed by symptoms or a physical exam alone.

Ibuprofen can help people feel much better while the antibiotic is taking effect. Gargling with warm salt water (one half teaspoon of salt in a glass of warm water) several times a day may also help.

Expectations (prognosis)
The probable outcome is good. Nearly all symptoms resolve in one week. Treatment prevents serious complications associated with streptococcal infections.


Calling your health care provider
See the article on sore throat for guidelines on when to call your health care provider. Call if you develop the symptoms of strep throat and you think you were exposed to someone with strep throat. Also, call if you are being treated for strep throat and are not feeling better within 24 to 48 hours.


Most people with strep are contagious until they have been on antibiotics 24-48 hours. Thus, they should stay home from school, daycare, or work until they have been on antibiotics for at least a day.

Get a new toothbrush after you are no longer contagious, but before finishing the antibiotics. Otherwise the bacteria can live in the toothbrush and re-infect when the antibiotics are done. Also, keep your family’s toothbrushes and utensils separate, unless they have been washed.

If repeated cases of strep still occur in a family, you might check to see if someone is a strep carrier. Carriers have strep in their throats, but the bacteria do not make them sick. Sometimes, treating them can prevent others from getting strep throat.

Johns Hopkins patient information

Last revised: December 7, 2012
by Mamikon Bozoyan, M.D.

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