Which of the following is a systemic complication of pharyngitis caused by Group A Streptococcus?

Acute rheumatic fever is a systemic complication that can arise following pharyngitis caused by Group A Streptococcus (GAS). This condition is an inflammatory response that occurs in some individuals after infection with GAS and is characterized by symptoms such as fever, carditis, arthritis, and potentially long-term damage to the heart valves. The relationship between GAS pharyngitis and acute rheumatic fever is well-established and arises due to the presence of certain streptococcal antigens that can provoke an autoimmune response.

Other conditions mentioned, such as hemolytic anemia, peritonsillar abscess, and scarlet fever, while associated with Group A Streptococcus, do not qualify as systemic complications of pharyngitis in the same way that acute rheumatic fever does. Hemolytic anemia is not directly related to pharyngitis; rather, it is a separate disorder. Peritonsillar abscess is a localized complication, resulting from the spread of infection, but it does not involve systemic manifestations. Scarlet fever, which is characterized by a rash and is caused by the same bacteria, represents a form of pharyngitis but is not classified as a systemic complication in the context of the long-term effects demonstrated by acute rheumatic fever.