Urticaria of the serum sickness type: Report of five cases

Abstract

1. 1. In five cases of urticaria a definite incubation period of five to nine days was noted and manifestations such as fever, joint and glandular swelling were present which are indicative of serum sickness. 2. 2. In four of five cases this condition was brought about by means other than injection; namely, ingestion, contact, and infection. 3. 3. For the purpose of differentiating between the serum sickness type and the allergic type of urticaria the clinical characteristics of serum sickness were investigated and the following criteria were noted: 3.1. a. In serum sickness the skin reactivity appears to be of a transitory character. This is indicated by the results of skin and passive transfer tests in 11 patients of serum sickness following injection of horse serum. 3.2. b. No eosinophilia was present in 16 consecutive cases of serum sickness following injections of horse serum. 3.3. c. The characteristic incubation period and the presence of symptoms usually associated with serum sickness are of diagnostic significance. 4. 4. In a survey of 168 consecutive cases of urticaria, only 22 per cent gave satisfactory skin reactions. Considering the great difficulties encountered in making the diagnosis of urticaria of the serum sickness type, and, on the other hand, the questionable skin reactivity in such cases, we believe that the incidence of this condition may not be uncommon.