Vaccination and smallpox never Smallpox may closely resemble
prevent. chicken pox; especially mild
cases.
AGE—usually before puberty, may Usually after puberty (many
occur in adults. exceptions.)
Initial stage practically absent. Initial stage severe, even in mild
cases.
TEMPERATURE,—no remission on Typical remission and secondary
onset of rash. fever.
White cells normal or decreased. Leukocytosis.
Prodromal rash very exceptional. Prodromal rash quite frequent.
Vesicles in crops. Vesicles never in crops.
Vesicles rarely shotty. Vesicles, following macules, are
hard and shotty.
RASH EVOLUTION,— RASH EVOLUTION,—
Very rapid, vesicles on first or Much slower, vesicles on seventh
second day. day.
Eruption is universal, successive Development progresses downward,
crops, most abundant on back, face first, then wrists,
begins on body, less on face, trunk, arms and lastly legs. Less
scalp, hands and feet. on trunk.
Vesicle is superficial and fluid Fluid pearl-colored and NOT
transparent. transparent. Thicker covering.
Halo (areola) usually absent. Areola is marked.
Involution is quite rapid. Involution is slow.
The =Secondary Toxic or Septic Rash= appears during the stage
of decrustation, sometimes with a mild fever. It may be either
scarlatiniform, morbilliform, or hemorrhagic. The skin immediately
surrounding the drying pocks is often exempt leaving an anemic halo.
The rash lasts about three days and fades or desquamates. With the
development of the skin eruption, an exanthem appears upon the mucous
membranes of the body cavities, developing into ulcers. This may
develop before the dermal rash and be of diagnostic importance.