ations.#

They are rounded, shallow excavations, with soft and reddish borders. In
exceptional instances exuberant granulations appear--_lupus
hypertrophicus_; or papillary outgrowths are noted--_lupus verrucosus_.
The ulcerations secrete a variable amount of pus, usually slight in
quantity, which leads to more or less crust formation; later, however,
cicatricial tissue, generally of a _firm and fibrous_ character,
results.

[Illustration: Fig. 45. Lupus of Arm.]

#In what manner does the disease spread?#

The patches spread by the appearance of new tubercles, or infiltrations
at the peripheral portion. New islets and areas of disease may continue
to make their appearance from time to time, usually upon contiguous
parts.

#Are the mucous membranes of the mouth, throat and larynx ever involved?#

In some instances, and either primarily or secondarily.

[Illustration: Lupus Vulgaris.]

[Illustration: Lupus Vulgaris.]

#Is the bone tissue ever involved in lupus vulgaris?#

No.

#What course does lupus vulgaris pursue?#

It is slowly but, as a rule, steadily progressive. Several years or more
may elapse before the area of disease is conspicuous.

#What is the cause of lupus vulgaris?#

It is now known to be due to the invasion of the cutaneous structures by
the tubercle bacillus; in short, a tuberculosis of the skin. It is not
infrequently observed in the strumous and debilitated. It is entirely
independent of syphilis.

#What is the pathology of lupus vulgaris?#

According to recent investigations, the infiltrations of lupus are due
chiefly to cell-proliferation and outgrowth from the protoplasmic walls
and adventitia of the bloodvessels and lymphatics. The fibrous-tissue
network, vessels and a portion of the cell infiltration are thus
produced, the fixed and wandering connective-tissue cells of the
inflamed stroma of the cutis being responsible for the other portion of
the new growth (Robinson).

#State the diagnostic features of lupus vulgaris.#

In a typical, developed patch of lupus are to be seen:--cicatricial
formation, usually of a fibrous and tough character; ulcerations; the
yellowish-brown tubercles and infiltration; and the characteristic soft,
small, yellowish or reddish-brown, cutaneous and subcutaneous points and
tubercles.

#How does the tubercular syphiloderm differ from lupus vulgaris?#

The tubercular syphiloderm is much more rapid in its course, the
ulceration i