Blanching of the skin by serum injection in scarlet fever

Abstract

scarlet fever, Schultz and Charlton 1 observed, the day following the injection of the serum, that the rash had faded around the point of injection. This blanching appeared to extend farthest along the lymphatics. They also found, by injecting intracutaneously from 0.5 to 1 c c of serum from normal persons or convalescents of scarlet fever, that there was a blanching of the rash for a distance of 1 cm. around the point of injection. This blanching was somewhat irregular in outline, appeared from 6 to 8 hours after the injection and persisted until the general rash had faded. The serums from several other animals did not produce such blanching. Neumann 2 obtained similar results, and in addition, he found that rashes from other causes, which resemble that in scarlet fever, were not extinguished by convalescent or normal serum. He also found that the serums from cases of diphtheria, measles and other exanthems reacted in the same way as normal serum, but that the serum from scarlet fever patients in the first four days of the disease did not produce the blanching. From these observations Neumann concludes that the blanching phenomenon may be a valuable aid in the differential diagnosis of scarlet fever. Schultz 3 more recently has confirmed the work of Neumann and his own earlier findings, and states that blanching occured in 1009^ of the cases when the injections were made on the second day of the rash, in 78% of 14 cases injected the third day of the rash, in 60^ of 5 cases each, injected on the first and fourth day of the rash, and in no case when injected on the fifth day. It is interesting to note that the results are as variable when injections are made on the first day as on the fourth day. Tron,4 making similar injections with human serums from various sources in 50 scarlet fever patients, concludes that the blanching phe-