Strep Infections

Streptococci cause many diseases and disorders. Some of them are listed below.

Symptoms vary, depending on where the infection is:

  • Cellulitis: The infected skin becomes red, and the tissue under it swells, causing pain.
  • Impetigo: Usually, scabby, yellow-crusted sores form.
  • Necrotizing fasciitis: The connective tissue that covers muscle (fascia) is infected. People have sudden chills, fever, and severe pain and tenderness in the affected area. The skin may appear normal until infection is severe.
  • Strep throat ( pharyngitis): This infection usually occurs in children 5 to 15 years old. Children under 3 years old seldom get strep throat. Symptoms often appear suddenly. The throat becomes sore. Children may also have chills, fever, headache, nausea, vomiting, and a general feeling of illness (malaise). The throat is beefy red, and the tonsils are swollen, with or without patches of pus. Lymph nodes in the neck are usually enlarged and tender. However, children under 3 years old may not have these symptoms. They may have only a runny nose. If people with a sore throat have a cough, red eyes, hoarseness, diarrhea, or a stuffy nose, the cause is probably a viral infection, not a streptococcal infection.
  • Scarlet fever: A rash appears first on the face, then spreads to the trunk and limbs. The rash feels like coarse sandpaper. The rash is worse in skinfolds, such as the crease between the legs and the trunk. As the rash fades, the skin peels. Red bumps develop on the tongue, which is coated with a yellowish white film. The film then peels, and the tongue appears beefy red (strawberry tongue).

Complications of streptococcal infections

If untreated, streptococcal infections can lead to complications. Some complications result from spread of the infection to nearby tissue. For example, an ear infection may spread to the sinuses, causing sinusitis, or to the mastoid bone (the prominent bone behind the ear), causing mastoiditis.

Other complications involve distant organs. For example, some people develop kidney inflammation (glomerulonephritis) or rheumatic fever.


  • For strep throat, clinical history and exam aided by rapid tests and/or culture of a sample taken from the throat. (Note: We don't culture on weekends or holidays. We rely on Clinical findings and our patients story on those days !)
  • For cellulitis and impetigo, often a doctor's evaluation
  • For necrotizing fasciitis, an imaging test (such as x-rays), culture, and often exploratory surgery

Different streptococcal diseases are diagnosed differently.

Strep throat

Doctors suspect strep throat based on the following:

  • Fever
  • Enlarged and tender lymph nodes in the neck
  • Pus in or on the tonsils
  • Absence of cough

The main reason for diagnosing strep throat is to reduce the chance of developing complications by using antibiotics. Because symptoms of group A strep throat are often similar to those of throat infection due to a virus (and viral infections should not be treated with antibiotics), testing with a throat culture or another test is necessary to confirm the diagnosis and to determine how to treat the infection.

Several diagnostic tests (called rapid tests) can be completed in minutes. For these tests, a swab is used to take a sample from the throat. If these results indicate infection (positive results), the diagnosis of strep throat is confirmed, and a throat culture, which takes longer to process, is not needed. However, results of rapid tests sometimes indicate no infection when infection is present (called false-negative results). If results are negative in children and adolescents, culture is needed. A sample taken from the throat with a swab is sent to a laboratory so that group A streptococci, if present, can be grown (cultured) overnight. In adults, negative results do not require confirmation by culture because the incidence of streptococcal infection and risk of rheumatic fever in adults is so low.

If group A streptococci are identified, they may be tested to see which antibiotics are effective (a process called susceptibility testing).

Cellulitis and impetigo

Cellulitis and impetigo can often be diagnosed based on symptoms, although culture of a sample taken from impetigo sores can often help doctors identify other microorganisms that may be the cause, such as Staphylococcus aureus.

Necrotizing fasciitis

To diagnose necrotizing fasciitis, doctors frequently use x-rays, computed tomography (CT), or magnetic resonance imaging (MRI) and culture. Exploratory surgery is often required to confirm the diagnosis.


  • Antibiotics (usually penicillin)
  • For necrotizing fasciitis, surgery to remove dead tissue

Strep throat

Strep throat usually resolves within 1 to 2 weeks, even without treatment.

Antibiotics shorten the duration of symptoms in young children but have only a modest effect on symptoms in adolescents and adults. Nevertheless, antibiotics are given to help prevent the spread of the infection to the middle ear, sinuses, and mastoid bone, as well as to prevent spread to other people. Antibiotic therapy also helps prevent rheumatic fever, although it may not prevent kidney inflammation (glomerulonephritis). Usually, antibiotics need not be started immediately. Waiting 1 to 2 days for culture results before starting antibiotics does not increase the risk of rheumatic fever. An exception is when a family member has or has had rheumatic fever. Then, every streptococcal infection in any family member should be treated as soon as possible.

Usually, penicillin or amoxicillin is given by mouth for 10 days. One injection of a long-lasting penicillin (benzathine) can be given instead. People who cannot take penicillin can be given erythromycin, clarithromycin, or clindamycinby mouth for 10 days or azithromycin for 5 days. The bacteria that cause strep throat have never been resistant to penicillin. In the United States, about 5 to 10% of these bacteria are resistant to erythromycin and related drugs (azithromycin and clarithromycin), but in some countries, more than 10% are resistant.

Fever, headache, and sore throat can be treated with acetaminophen or nonsteroidal anti-inflammatory drugs (NSAIDs), which reduce pain and fever. However, children should not be given aspirin because it increases the risk of Reye syndrome. Neither bed rest nor isolation is necessary.

Other streptococcal infections

Serious streptococcal infections (such as necrotizing fasciitis, endocarditis, and severe cellulitis) require penicillin, given intravenously, sometimes with other antibiotics.

People with necrotizing fasciitis are treated in an intensive care unit (ICU). In necrotizing fasciitis, dead, infected tissue must be surgically removed.

More Information

Centers for Disease Control and Prevention: Group A Streptococcal Disease