Diffuse vasculitis, eosinophilia, and elevated antibody titre to measles virus.

In the original description of serum sickness by Von Pirquet and Schick (1905) vasculitis was described as a feature. This was subsequently shown to be due to circulating immune complexes, which are known to be eosinotactic. The following report describes a case of serum sickness, occurring in a 14-year-old boy, characterized by diffuse vasculitis with communicating hydrocephalus and accompanied by a pronounced eosinophilia. A significantly raised antibody (IgG) titre to measles virus was demonstrated in his serum and indicated that this agent probably provided the initial antigenic stimulus.