Created in 1969, this chart lists the major features used when differentiating between the viral diseases smallpox, and chickenpox. The three primary criteria include Fever, Rash characteristics, and Death rate.
- The onset of fever in the case of smallpox takes place 2 - 4 days before the onset of the maculopapular rash, while in the case of chickenpox, the onset of the fever takes place at the same time as the onset of the rash.
- The appearance, and development of the rash in the case of smallpox is slow in its development, and the crop of papules all develop in a single stage, while in the case of chickenpox, the pocks develop rapidly, and take place in several stages.
- The distribution of the smallpox rash is described as being greater on the arms and legs, while in the case of chickenpox, the rash distribution is greatest on the body. The involvement of the palms and soles in the rash distribution can also help to identify smallpox from chickenpox. In the case of smallpox, involvement of the palms and soles is usually present, while in the case of chickenpox, involvement of the these regions is usually absent.
- As to the death rate between these two diseases, in the case of smallpox, the death rate is 1 in 10, while in the case of chickenpox, the death rate is said to be very uncommon.