Group A strep causes strep throat. Strep pyogenes, a gram-positive bacterium, is the main etiologic agent of Group A strep infections. Colonization of the upper respiratory tract is possible. The incubation period of strep throat is two to five days. Strep throat is associated with a very painful sore throat, fever, and abdominal pain. Impetigo is another superficial group a strep infection that is a skin infection that typically involves the face and lower extremities. The skin infection of impetigo is papules that become vesicles with surrounding erythema and crust over. Children most commonly develop impetigo. Rheumatic fever occurs following Group a strep infection that is not effectively treated or not treated in up to 3 percent of cases. Rheumatic fever is a potentially severe complication of Group a strep infection due to its association with immune-mediated damage to cardiac valves (most commonly the mitral valve or aortic valve) in Rheumatic fever. Post-streptococcal glomerulonephritis is another immune-mediated disease seen following some group a strep infections. Post-streptococcal glomerulonephritis is a potentially serious complication of Group a strep infection. Penicillin is the treatment of choice for Group a strep, strep throat, and more than mild impetigo. Mild impetigo can be treated with topical mupirocin. Group A Strep: Return to school/ work is 24 hours after starting antibiotics (penicillin or amoxicillin). The patient also needs to be afebrile. Group a strep can also cause invasive disease, possibly resulting in septic arthritis, sepsis, cellulitis that may progress into necrotizing fasciitis, or strep toxic shock syndrome that may involve multi-systems. Invasive Group a strep infections are usually treated with penicillin and clindamycin. Surgical debridement of necrotic tissue may be needed for cases of necrotizing fasciitis. Eradication of Group a strep colonization is typically not attempted. Eradication of Group a strep colonization may be required in outbreaks of Group a strep infections to control the outbreak. There is no vaccine for Group a strep.

References:

Strep Throat: All You Need to Know | CDC
 

Mosites E, Kaplan EL, Li YL, Van Beneden CA. The Group A Streptococcus. In: Boulton ML, Wallace RB. eds. Maxcy-Rosenau-Last Public Health & Preventive Medicine, 16e. McGraw Hill; 2022. Accessed January 08, 2022