Staphylococcal scarlet fever: role of pyrogenic exotoxins.

Staphylococcal pyrogenic exotoxin (PE) types A and B were tested for their role in production of a scarlatiniform rash. The PEs elicited minimal skin reactions after intracutaneous injection into animals not presensitized to the toxins. In contrast, erythematous injection into animals not presensitized to the toxins. In contrast, erythematous and edematous rashes were produced after administration of either PE to animals presensitized to homologous toxin. After 3 to 4 days, the erythematous areas showed membranous desquamation. Staphylococcal PEs also enhanced delayed and Arthus hypersensitivity skin reactions developed against unrelated proteins; the reactions subsequently desquamated. In addition, animals previously sensitized to either staphylococcal PE type developed scarlatiniform rashes after challenged with heterologous staphylococcal or any group A streptococcal PE. The data suggest that staphylococcal PEs produce scarlet fever-like rashes comparable to group A streptococcal PEs and that all PE types contain a common core moiety against which delayed hypersensitivity may be developed.