sent, of syphilis.

#Describe the tubercular eruption of syphilis.#

The _tubercular syphiloderm_ (_syphiloderma tuberculosum_) may
exceptionally occur within the first year as a more or less generalized
eruption. As a rule, however, it is a late manifestation, at times
appearing many years after the initial lesion; is limited in extent, and
shows a decided tendency to occur in groups, often forming segments of
circles and circular areas, clearing in the centre and spreading
peripherally.

It consists (as a late, limited manifestation) of several or more firm,
circumscribed, deeply-seated, smooth, glistening or slightly scaly
elevations; rounded or acuminated in shape, of a yellowish-red,
brownish-red or coppery color and usually of the size of small or large
peas. Several groups may coalesce, and a serpiginous tract result
(_serpiginous tubercular syphiloderm_). The lesions develop slowly, and
are sluggish in their course, remaining, at times, for weeks or months,
with but little change. As a rule, however, they terminate sooner or
later, either by absorption, leaving a more or less permanent pigment
stain with or without slight atrophy (_non-ulcerating tubercular
syphiloderm_), or by ulceration (_ulcerating tubercular syphiloderm_).

[Illustration: Fig. 58. Ulcerating Tubercular Syphiloderm.]

#Describe the ulcerating tubercular syphiloderm.#

The ulceration may be superficial or deep in character, and involve
several or all of the lesions forming the group. The patch may consist,
therefore, of small, discrete, punched-out ulcers, or of one or more
continuous ulcers, segmented, crescentic or serpiginous in shape. They
are covered with a gummy, grayish-yellow deposit or they may be crusted.
As the ulcerative changes take place, new lesions, especially about the
periphery of the group or patch, may appear from time to time.

[Illustration: Tubercular Syphiloderm.]

[Illustration: Large-pustular Syphiloderm.]

In some instances, more especially about the scalp, the surface of the
ulcerations becomes papillary or wart-like, with an offensive,
yellowish, puriform secretion (_syphilis cutanea papillomatosa_).

#From what diseases is the tubercular syphiloderm to be differentiated?#

From tubercular leprosy, epithelioma and lupus vulgaris, especially the
last-named.

#What are the chief diagnostic characters of the tubercular syphiloderm?#

The tendency to form segments, crescents and circles, the color