574 ANAPHYLAXIS IN RELATION TO INFECTION AND IMMUNITY 



TABLE 22 TIME OF APPEARANCE OF SERUM RASH IN 430 CASES OF 



SERUM DISEASE 



In this table are included some cases of reinjection, as, e. g., scarlet- 

 fever patients who received a routine immunizing dose of antitoxin 

 upon admission, and another after having contracted diphtheria; also 

 cases of diphtheria that became reinfected within a few months after 

 their discharge from the hospital. As will be seen, about 63 per cent, 

 of cases develop a rash between the sixth and the ninth day after the 

 injection of antitoxin. 



Three main types of rashes are generally recognized : 



1. Urticarial Rashes. If we include in this group all eruptions that 

 present a resemblance to urticaria, these rashes are the most common, 

 constituting from 70 to 90 per cent, of all eruptions. They usually 

 appear after the seventh day, becoming manifest first about the site of 

 injection. Large, irregularly shaped, and scattered blotches appear, 

 frequently with true wheals in the center (Fig. 119), accompanied by 

 intense itching and irritation. Sometimes true wheals do not appear. 

 The rash is often very profuse, and fresh blotches may continue to ap- 

 pear for two or three days. Occasionally, the rash is quite sparse and 

 mild, and may disappear within twenty-four hours. 



2. Multiform Rashes. This type of rash is quite common. It is 

 often circinate in its arrangement, or occurs in large blotches mixed with 

 a scattered morbilliform or measly form of rash (Fig. 120). Different 

 parts of the body may present different appearances at the same time. 

 This rash may occasionally closely simulate true measles, especially 

 since it involves the face, and as the conjunctive are likely to be con- 



