Arthritis and vasculitis during the incubation period of varicella.

Arthritis and vasculitis are very rare complications of varicella occurring almost exclusively after the eruption of the characteristic rash. We report two children, aged three and seven years, who developed vasculitis and polyarthritis (patient No. 1) and arthritis (patient No. 2) 13 and 9 days, respectively, before the onset of their typical varicella. Arthritis and vasculitis so early in the incubation period of varicella have not been described previously. In all previously reported cases the arthritis occurred after or together with the onset of varicella and only in one instance preceded the exanthem by 2 days. Although this may have been an unfortunate coincidence, an association between varicella zoster virus and these manifestations should be seriously considered. Clinicians confronted with such cases must be cautious and search for varicella infection, especially in times of epidemics.