Which toxin produced by S. pyogenes is known to cause fever and rash?

The erythrogenic toxin, produced by Streptococcus pyogenes, is specifically known for causing fever and rash, characteristic symptoms of scarlet fever. This toxin acts as a superantigen that activates a massive immune response by stimulating T cells, which results in the release of cytokines. This surge in cytokines can lead to systemic symptoms such as fever. Furthermore, the erythrogenic toxin is responsible for the distinctive red rash associated with scarlet fever, as it affects blood vessels and leads to increased permeability.

In contrast, other toxins like hyaluronidase primarily aid in tissue invasion rather than causing systemic symptoms like fever and rash. Exotoxin A and exotoxin B, while also associated with pathogenicity, do not have the same association with scarlet fever or cause the specific symptomatology of fever and rash that characterizes infections associated with erythrogenic toxin. Thus, the link between the erythrogenic toxin and its role in causing fever and rash highlights its significance in understanding the pathology of infections caused by S. pyogenes.