ons. It
may also present the appearance of a serpiginous lupus vulgaris or
syphiloderm. As a rule it is slow in its course. Furuncular or
abscess-like formations may develop, usually from secondary infection.
The disease is due to the invasion of the cutaneous tissues by the
blastomyces.

[Illustration: Blastomycetic dermatitis.]

Treatment consists in administration of moderate to large doses of
potassium iodide, and in the employment of antiseptic and parasiticide
applications; usually, however, radical treatment, such as employed in
lupus vulgaris, may be necessary.

#Scabies.#
(_Synonym:_ The Itch.)

#What is scabies?#

Scabies, or itch, is a contagious animal-parasitic disease characterized
by a multiform eruption of a somewhat peculiar distribution, attended by
intense itching.

#Describe the symptoms of scabies.#

The penetration and presence of the parasites within the cutaneous
structures besides often giving rise to several or more complete or
imperfectly formed _burrows_, excite varying degrees of irritation, and
in consequence the formation of vesicles, papules and pustules,
accompanied with more or less intense itching. Secondarily, crusting,
and at times a mild or severe grade of dermatitis, may be brought about.
The parasite seeks preferably tender and protected situations, as
between the fingers, on the wrists, especially the flexor surface, in
the folds of the axilla, on the abdomen, about the anal fissure, about
the genitalia, and in females also about the nipples, and hence the
eruption is most abundant about these regions. The inside of the thighs
and the feet are also attacked, as, indeed, may be almost every portion
of the body. The scalp and face are not involved; exceptionally,
however, these parts are invaded in infants and young children.

#Is the grade of cutaneous irritation the same in all cases of scabies?#

No; in those of great cutaneous irritability, especially in children,
the skin being more tender, the type of the eruption is usually much
more inflammatory. In those predisposed a true eczema may arise, and
then, in addition to the characteristic lesions of scabies, eczematous
symptoms are superadded; in long-persistent cases, indeed, the burrows
and other consequent lesions may be more or less completely masked by
the eczematous inflammation, and the true nature of the disease be
greatly obscured.

#