Eczema vaccinatum. Disseminated vaccinia was the most dreaded complication of smallpox vaccination. Like eczema herpeticum, eczema vaccinatum occurred in children with underlying eczematous disorders. It was more serious because of the severity of the acute illness, the tendency toward scarring, and a higher incidence of mortality. The above figure suggests that the scarring from eczema vaccinatum can be disfiguring.