As in all of these contagious diseases there is much variation in the
severity of the individual case. Most cases of chicken pox are mild
affairs. There is no fever or general disturbance, only the eruption
of a mild or moderate sort. In a few individuals the disease assumes a
severe form, in which case, fever, headache, backache and chilliness
precede the eruption for a day. This is especially apt to occur in
adults, but children may have some fever, and be generally unwell for
a day or so before the eruption appears. Preceding the characteristic
eruption there sometimes appears a day or so earlier a redness of
the skin which has often been looked upon as scarlet fever until the
typical eruption has developed.
The individual lesions of the chicken pox eruption pass through an
evolution which is often very rapid. There is first a pink blotch or
spot which soon is a little elevated above the skin, and disappears
when pressed upon. Soon this is replaced by a vesicle or water blister.
The vesicles are very near the surface of the skin and have a very
thin covering, so that they often look like drops of water lying on
the skin. The covering is soon broken, the fluid escapes, and as
drying occurs a little crust or scab is left. This separates after
several days. There is great variation in the number of these lesions.
Sometimes only two or three develop. In severe cases the lesions are
very closely placed on the body so that the finger can hardly be
placed at any point between them. In the average case the lesions lie
two or three inches apart. The distribution upon the body is quite
characteristic. Most lesions are located on the parts of the body
covered by clothing. In mild and moderate cases the eruption is almost
confined to the trunk, but some lesions are also seen upon the arms,
legs and forehead. In severe cases rather abundant eruption appears on
the face, arms and legs. The lesions develop in the scalp, palms of
the hands and soles of the feet in limited numbers especially in more
severe cases. In such instances also, vesicles appear in the mucous
membrane of the mouth, especially on the palate, and as they rupture
they leave very sensitive points which are painful when food is taken.
One of the most characteristic things of the chicken pox eruption is
that the lesions appear in crops. By the time the first lesions have
reached the crusting stage others are present which are still vesicles,
and still younger ones appear as pink spots. New lesions continue to
appear for 3 or 4 days. In parts of the body where the skin is thick as
on the palms of the hands, soles of the feet and forehead, the vesicles
may remain unruptured for some time in which case the contents becomes
yellowish and the surrounding skin reddened. If the skin has been
rendered specially susceptible by any cause, the eruption is apt to be
more severe. When chicken pox follows upon scarlet fever the eruption
is apt to be profuse. Upon parts of the body which have been recently
burned by the sun or subject to irritation under a surgical dressing,
cast, or diaper, the eruption is more abundant than on other portions
of the body.