ct well in some cases, applied in
five- to ten-per-cent. strength, as ointments.

In obstinate patches the _x_-ray may be resorted to, employing it with
caution and in the same manner as in other diseases.

#Pityriasis Rosea.#
(_Synonym:_ Pityriasis Maculata et Circinata.)

#What do you understand by pityriasis rosea?#

Pityriasis rosea is a disease of a mildly inflammatory nature,
characterized by discrete, and later frequently confluent, variously
sized, slightly raised scaly macules of a pinkish to rosy-red, often
salmon-tinged, color.

#Upon what part of the body is the eruption usually found?#

The trunk is the chief seat of the eruption, although not infrequently
it is more or less general.

#Describe the symptoms of pityriasis rosea.#

The lesions, which appear rapidly or slowly, are but slightly elevated,
somewhat scaly, usually rounded, except when several coalesce, when an
irregularly outlined patch results. At first they are pale or bright
pink or reddish, later a salmon tint (which is often characteristic) is
noticed. The scaliness is bran-like or flaky, of a dirty gray color,
and, as a rule, less marked in the central portion; it is never
abundant. The skin is rarely thickened, the process being usually
exceedingly superficial.

#What course does pityriasis rosea pursue?#

The eruption makes its appearance, as a rule, somewhat rapidly, usually
attaining its full development in the course of one or two weeks, and
then begins gradually to decline, the whole process occupying one or two
months.

#To what is pityriasis rosea to be attributed?#

The cause is not known; it is variously considered as allied to
seborrh[oe]a (eczema seborrhoicum), as being of a vegetable-parasitic
origin, and as a mildly inflammatory affection somewhat similar to
psoriasis. It is not a frequent disease.

#How is pityriasis rosea distinguished from ringworm, psoriasis and the
squamous syphiloderm?#

From ringworm, by its rapid appearance, its distribution, the number of
patches, and, if necessary, by microscopic examination of the scrapings.

Psoriasis is a more inflammatory disease, is seen usually more
abundantly upon the limbs, the scales are profuse and silvery, and the
underlying skin is red and has a glazed look; moreover, psoriasis, as a
rule, appears slowly and runs a chronic course.

The squamous syphiloderm differs in its history, distribution, and above
a