Diagnosis of Group A Streptococcus
Acute pharyngitis is one of the most frequent illnesses for which primary care physicians
are consulted. Although Group A Strep is the most common bacterial cause of acute
pharyngitis, not all patients with this condition are infected by Group A Strep.
While other forms of pharyngitis display the same symptoms, Group A Strep pharyngitis
is the only commonly occurring form of acute pharyngitis for which antibiotic
therapy is definitely indicated. Therefore, unless the physician is able to exclude
Group A Strep on epidemiological and clinical grounds, a laboratory test should
be performed for the bacteria.
Important, updated information on diagnostic tests and how to choose the ones for
The most severe diseases caused by invasive Group A Strep are necrotizing fasciitis
and STSS, so physicians should be alert for the signs and symptoms of both.
- Early signs and symptoms of necrotizing fasciitis:
- Severe pain and swelling, often rapidly increasing
- Redness at a wound site
- Early signs and symptoms of STSS:
- Abrupt onset of generalized or localized severe pain, often in an arm or leg
- Influenza-like syndrome
- A flat red rash over large areas of the body (only occurs in 10% of cases)2
IDSA 2012 Guidelines. Bisno, Alan et al. "Clinical Practice Guideline for the Diagnosis
and Management of Group A Streptococcal Pharyngitis: 2012 Update by the Infectious
Diseases Society of America